# Dosing HCL, post your experiences



## yusufsarac (Feb 20, 2017)

This thread seems to be very interesting  Subscribing...


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## burr740 (Feb 19, 2014)

Interesting. Ive been wondering if a direct blast would kill algae. My fish think its feeding time and they usually take a direct hit. So far hasnt seemed to phase them. I always add it to the strongest current though, so they arent in the middle of it long.

Fwiw Alagaefix per directions would knock that algae out with a quickness. It does a real number on hair types. Other types, not so much. Dont use it with shrimp though


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## yusufsarac (Feb 20, 2017)

I'm thinking to add it to the water which is resting for the water change. in the middle of the week, drop KH this way and at the weekend make the water change with that water. Would it be good approach ? instead of adding HCL directly to the tank


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## burr740 (Feb 19, 2014)

That would be good, yes


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## vvDO (Oct 18, 2010)

burr740 said:


> Interesting. Ive been wondering if a direct blast would kill algae. My fish think its feeding time and they usually take a direct hit. So far hasnt seemed to phase them. I always add it to the strongest current though, so they arent in the middle of it long.
> 
> Fwiw Alagaefix per directions would knock that algae out with a quickness. It does a real number on hair types. Other types, not so much. Dont use it with shrimp though




I have 1 amano shrimp that’s been in this tank more than 8 years... I’d hate to kill it just to get rid of the algae, so the algae lives on.



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## cl3537 (Jan 28, 2019)

burr740 said:


> Interesting. Ive been wondering if a direct blast would kill algae. My fish think its feeding time and they usually take a direct hit. So far hasnt seemed to phase them. I always add it to the strongest current though, so they arent in the middle of it long.
> 
> Fwiw Alagaefix per directions would knock that algae out with a quickness. It does a real number on hair types. Other types, not so much. Dont use it with shrimp though


Unless you are going to dry spot dose HCL and burn/kill every living thing in proximity to the dose, (I have put holes in my t-shirts splashing 5M lab grade HCL when cleaning) as an algaecide in solution it makes no sense whatsoever.

HCL in solution raise H+ and lower pH once dissolved and mixed. I'd much rather add acids I can add as a salt than 'mystery concentration' solutions. As an algaecide this is a complete bust for me.


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## Immortal1 (Feb 18, 2015)

For my situation I will be adding the HCL to the 20g holding tank under my main 75g display tank. For HCL I will be using this product from Menards. According to the technical data sheet it is roughly 32% Hydrogen Chloride. 

After reading thru @burr740 post on his journal, it sounds like 3ml of this percentage of HCL should drop the 20g of holding tank water about 2dKH. 

The nice thing about having the holding tank is I can experiment as needed. If I don't like the results I just pump the contents down the drain and start over. At $3.55 per gallon, I suspect I will never use it all


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## varanidguy (Sep 8, 2017)

Is this something that is permanent and safe?

I ask because my tap water is about 4-5 dKH - I would like to use aquasoil in some tanks. Could I use HCL to get rid of the KH before using it in tanks with aquasoil safely, without harming shrimp, fish, plants, etc?


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## vvDO (Oct 18, 2010)

cl3537 said:


> Unless you are going to dry spot dose HCL and burn/kill every living thing in proximity to the dose, (I have put holes in my t-shirts splashing 5M lab grade HCL when cleaning) as an algaecide in solution it makes no sense whatsoever.
> 
> HCL in solution raise H+ and lower pH once dissolved and mixed. I'd much rather add acids I can add as a salt than 'mystery concentration' solutions. As an algaecide this is a complete bust for me.




Definitely not the purpose of dosing HCl, just kinda happened as I dosed with a syringe with a long needle the tip was right above the algae and I literally squirted 0.5 mL and posted my observation. I do not endorse the direct use of HCl as an algaecide.

Due to my observation, and concern that it may burn plants or fish, I plan to always drip it in slowly in an area of strong flow if I am dosing into the aquarium. From now on I will only be dosing a holding tank during water changes unless of course I forget. I have 2 12 gallon plastic containers that I fill and temp correct before water changes.


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## varanidguy (Sep 8, 2017)

vvDO said:


> Definitely not the purpose of dosing HCl, just kinda happened as I dosed with a syringe with a long needle the tip was right above the algae and I literally squirted 0.5 mL and posted my observation. I do not endorse the direct use of HCl as an algaecide.
> 
> Due to my observation, and concern that it may burn plants or fish, I plan to always drip it in slowly in an area of strong flow if I am dosing into the aquarium. From now on I will only be dosing a holding tank during water changes unless of course I forget. I have 2 12 gallon plastic containers that I fill and temp correct before water changes.
> 
> ...


How long does it take for the acid to take effect and get rid of the KH?


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## cl3537 (Jan 28, 2019)

vvDO said:


> Definitely not the purpose of dosing HCl, just kinda happened as I dosed with a syringe with a long needle the tip was right above the algae and I literally squirted 0.5 mL and posted my observation. I do not endorse the direct use of HCl as an algaecide.
> 
> Due to my observation, and concern that it may burn plants or fish, I plan to always drip it in slowly in an area of strong flow if I am dosing into the aquarium. From now on I will only be dosing a holding tank during water changes unless of course I forget. I have 2 12 gallon plastic containers that I fill and temp correct before water changes.
> 
> ...


Mix it before in a jug or bucket with tank water changes. No need to expose livestock to concentrated acid ever.


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## vvDO (Oct 18, 2010)

varanidguy said:


> How long does it take for the acid to take effect and get rid of the KH?




I did not measure the change... I believe Burr noticed a drop very quickly, I think he measured KH about 15 minutes after dosing.


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## varanidguy (Sep 8, 2017)

vvDO said:


> I did not measure the change... I believe Burr noticed a drop very quickly, I think he measured KH about 15 minutes after dosing.
> 
> 
> Sent from my iPhone using Tapatalk


Wow very nice. Have you found this method to be stable, as in, the KH remains gone indefinitely?


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## vvDO (Oct 18, 2010)

varanidguy said:


> Wow very nice. Have you found this method to be stable, as in, the KH remains gone indefinitely?



That’s the idea, you need to keep up with new water during water changes to maintain it.

Let me point you to where it all got started for me... worth a read through, many good posts further down as well.

120 Gal Dutchy Freestyle - Now with 35% less water volume!
https://r.tapatalk.com/shareLink?sh...forums/showthread.php?p=11190415&share_type=t




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## varanidguy (Sep 8, 2017)

vvDO said:


> That’s the idea, you need to keep up with new water during water changes to maintain it.
> 
> Let me point you to where it all got started for me... worth a read through, many good posts further down as well.
> 
> ...


Thank you for the link and this thread! It might be a cheaper alternative to getting an RO system since it would be for a nano tank with aqua soil. All I'd really want to do is remove KH to keep the soil from becoming exhausted.


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## Greggz (May 19, 2008)

Man I hope you guys are taking the proper precautions and have the right type of facility to be working with HCL.

Here's Burr's lab to give an idea of what he is up to.........................................


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## Immortal1 (Feb 18, 2015)

LOL, the lab pic returns


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## varanidguy (Sep 8, 2017)

Greggz said:


> Man I hope you guys are taking the proper precautions and have the right type of facility to be working with HCL.
> 
> Here's Burr's lab to give an idea of what he is up to.........................................


HA!

Wouldn't this stuff be more diluted and safer to work with? https://www.homedepot.com/p/Klean-Strip-1-gal-Green-Muriatic-Acid-GKGM75006/202690263


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## Greggz (May 19, 2008)

Immortal1 said:


> LOL, the lab pic returns


An oldie but goodie!

Seemed appropriate to bust it out again.:grin2:


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## Immortal1 (Feb 18, 2015)

The Home Depot product, Klean Strip - Muriatic Acid is also a 32% product at listed here


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## varanidguy (Sep 8, 2017)

Immortal1 said:


> The Home Depot product, Klean Strip - Muriatic Acid is also a 32% product at listed here


Thank you, Immortal!

OP, sorry to hijack your thread.


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## burr740 (Feb 19, 2014)

Dammit @Greggz I asked you to not post pictures of my house!

And yeah I dont think anyone is gonna use HCL to kill algae, it was just an idle curiosity


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## yusufsarac (Feb 20, 2017)

varanidguy said:


> Wow very nice. Have you found this method to be stable, as in, the KH remains gone indefinitely?


I'm no expert in chemistry but I did look it up little bit. It seems HCl burns the Carbonate permenantly. This is the reaction

CaCO3 + HCl → CaCl2 + H2O + CO2 

I believe it is not CaCO3 in the tank, but the reaction would be the same. So it converts to Co2 and H2O and CaCl2 (again not sure of CaCl2) and the co2 is removed from the water as gas. So I think it would be permenant. Any thoughts ?


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## varanidguy (Sep 8, 2017)

I'm also curious, aside from the obvious safety concerns while handling the acid, is there any downside or dangerous side-effect for plants or livestock?


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## burr740 (Feb 19, 2014)

Yep, its permanent


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## Immortal1 (Feb 18, 2015)

For what it's worth - the Mad Scientist is playing around with unstable chemicals as I type... (boom)
5 minute readings after dosing 3ml 32% HCL to 20g water. 
Results to follow... :nerd:

Bump:
5:10pm / 7.2pH / 5.0dKH - added 3ml 32% Sunnyside Muratic Acid
5:15pm / 6.9pH / 4.5dKH
5:20pm / 6.9pH / 4.0dKH
5:25pm / 6.9pH / 4.0dKH
5:30pm / 7.0pH / 4.0dKH


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## burr740 (Feb 19, 2014)

3 ml might drop 20 gal a point


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## Immortal1 (Feb 18, 2015)

burr740 said:


> 3 ml might drop 20 gal a point


In my opinion, that is exactly what it did.
6ml coming up shortly :grin2:

Dr. Fahrenkrug's Lab


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## vvDO (Oct 18, 2010)

Immortal1 said:


> The Home Depot product, Klean Strip - Muriatic Acid is also a 32% product at listed here




My local HD doesn’t carry that, only this, which I believe is simply a lower concentration therefore less fumes as the advertisement states. Wish they would post the amount.

https://www.homedepot.com/p/Klean-Strip-1-gal-Green-Muriatic-Acid-GKGM75006/202690263

There’s also an HDX brand muriatic acid for pools which is about 15% almost same price for 2 gallons, may be “safer” to handle. If this works well I may consider it.



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## vvDO (Oct 18, 2010)

Greggz said:


> Man I hope you guys are taking the proper precautions and have the right type of facility to be working with HCL.
> 
> 
> 
> Here's Burr's lab to give an idea of what he is up to.........................................















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## Immortal1 (Feb 18, 2015)

vvDO said:


> My local HD doesn’t carry that, only this, which I believe is simply a lower concentration therefore less fumes as the advertisement states. Wish they would post the amount.
> 
> https://www.homedepot.com/p/Klean-Strip-1-gal-Green-Muriatic-Acid-GKGM75006/202690263
> 
> ...


Interesting how even the manufacturer won't list what the HCL level is (<30%). I will concur, the Sunnyside Muriatic Acid does have a definite odor when you are adding it to water.
If you wish to use this process, I would suggest doing what I am doing - find an old 20g tank and do some experimenting to figure out how much of a KH drop you get for XX amount of product.


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## Greggz (May 19, 2008)

vvDO said:


>


LOL!

Proves that humor is always funniest when based in truth.

Looks to me like the correct gear you HCL guys should be wearing for water changes!:grin2:


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## varanidguy (Sep 8, 2017)

Is there a limit? Say it takes 9 ml to get rid of 4 dKH in 10 gallons of water, would the concentration lead to toxicity for inhabitants or plants?


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## Immortal1 (Feb 18, 2015)

@varanidguy - cannot answer that one.


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## Maryland Guppy (Dec 6, 2014)

This is a very permanent drop in alkalinity.
Bicarbonates and/or carbonates will be removed.
Nothing like pH swings from CO2 injection.

Safety: try not to get it on you or your clothes.
Skin contact use water and rinse well immediately, key is don't wait to rinse it off.

Algaecide = no
That algae that died just took the hit from a reaction.

People use this in their pools all the time.

Glassware is best, plastic is okay.
Pipettes used to measure should be relatively new.
How many have had an old pipette fail and split on the seam?>

Warning keep some KH behind or else the pH will plummet when all alkalinity is gone.


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## varanidguy (Sep 8, 2017)

Maryland Guppy said:


> This is a very permanent drop in alkalinity.
> 
> Bicarbonates and/or carbonates will be removed.
> 
> ...




What about if you already have relatively soft tap water and you want to use aquasoil without investing in an RO unit? 


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## Immortal1 (Feb 18, 2015)

Round 2 data:
6:00pm / 7.1pH / 5dKH - 6ml 32% HCL added to 20g water
6:05pm / 6.2pH / 3dKH 
6:10pm / 6.2pH / 3dKH
6:15pm / 6.1pH / 3dKH
6:20pm / 6.1pH / 3dKH
6:30pm / 6.2pH / 3dKH
6:40pm / 6.3pH / 3dKH
6:50pm / 6.4pH / 3dKH
7:05pm / 6.7pH / 3dKH

Pretty cool process - would never have guessed it worked this easily.


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## cl3537 (Jan 28, 2019)

Maryland Guppy said:


> Bicarbonates and/or carbonates will be removed.


Not exactly, nothing is removed precipitated out, it just pushes the equilibrium towards Carbonic Acid.
Add Ammonia or another based and you will raise your kH.


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## TexMoHoosier (Dec 14, 2016)

Carbonic acid (H2CO3) is unstable and decomposes to CO2 and H2O. Carbon in bicarbonates and bicarbonates off gases as CO2, so adding a base will raise the pH, but does not reverse the reaction to bring the KH back up.


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## Maryland Guppy (Dec 6, 2014)

cl3537 said:


> Not exactly, nothing is removed precipitated out, it just pushes the equilibrium towards Carbonic Acid.
> Add Ammonia or another based and you will raise your kH.


Close enough, if I don't add it back KH remains low or gone.


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## vvDO (Oct 18, 2010)

cl3537 said:


> Not exactly, nothing is removed precipitated out, it just pushes the equilibrium towards Carbonic Acid.
> 
> Add Ammonia or another based and you will raise your kH.




Gassed out. The reaction quickly goes to CO2 which is released as a gas. HCO3- is CO2 dissolved in water.




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## Maryland Guppy (Dec 6, 2014)

I always like it when the "Captain" is involved.
A chart and real data is provided, thanks @Immortal1 
Reminds me of the ammonia consumption trial, that was impressive!

I'll have to give this a try now.

Starting with the quarterly WC 33G plant only tank.
It's not like I need the plants to grow any better.
If this helps them grow I will curse you all! :grin2:


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## cl3537 (Jan 28, 2019)

vvDO said:


> Gassed out. The reaction quickly goes to CO2 which is released as a gas. HCO3- is CO2 dissolved in water.
> 
> Sent from my iPhone using Tapatalk


I wouldn't have thought it would all be gassed out but not sure never tried it.


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## vvDO (Oct 18, 2010)

2 days ago was 24 hours after my first dose into my 20L, KH was 3. That was after 3 mL. I know my HCL concentration is lower than others less than 30% for sure. My KH may have also been higher and closer to 4 than 3 to start. I dosed 3 mL more in slow increments, to bring the total up to 6 mL. Last night I checked KH and it’s down to 2. Last night I also dosed 1.5 mL and I think I’m going to stop there. From now on I will treat my tap water down to KH of 1 before water changes.

So far I’ve noticed some increased pearling overall, where I haven’t seen much pearling at all before this. I am sure the lower overall pH is making some nutrients more available to plants. Color of macandra has also improved, new growth a bright pink. I have seen no change in the fuzzy green algae on old growth which I have been dealing with for a long time, I’m hoping as plants are healthier, this algae will also lessen. BBA has also lessened in the last week, I cannot attribute this to HCl since I’ve noticed a reduction even before I started lowering KH.


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## varanidguy (Sep 8, 2017)

vvDO said:


> 2 days ago was 24 hours after my first dose into my 20L, KH was 3. That was after 3 mL. I know my HCL concentration is lower than others less than 30% for sure. My KH may have also been higher and closer to 4 than 3 to start. I dosed 3 mL more in slow increments, to bring the total up to 6 mL. Last night I checked KH and it’s down to 2. Last night I also dosed 1.5 mL and I think I’m going to stop there. From now on I will treat my tap water down to KH of 1 before water changes.
> 
> So far I’ve noticed some increased pearling overall, where I haven’t seen much pearling at all before this. I am sure the lower overall pH is making some nutrients more available to plants. Color of macandra has also improved, new growth a bright pink. I have seen no change in the fuzzy green algae on old growth which I have been dealing with for a long time, I’m hoping as plants are healthier, this algae will also lessen. BBA has also lessened in the last week, I cannot attribute this to HCl since I’ve noticed a reduction even before I started lowering KH.
> 
> ...


Thank you for this thread. I may try experimenting with this myself. Have you taken note how much it raises TDS, if much at all?


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## kgbudge (Feb 8, 2019)

Maryland Guppy covered most of it, but:

HCl is dangerous only when concentrated. It leaves residual chloride, which is actually a minor plant nutrient. Very safe once diluted

It immediately converts bicarbonate to carbonic acid, which then takes a few minutes to break down to dissolved carbon dioxide. Then the dissolved carbon dioxide diffuses out of the water on a time scale of hours, unless you take special measures to aerate it. At first the pH drops dramatically. As the carbonic acid breaks down to carbon dioxide and diffuses out of the tank, the pH bounces back up, though not to its previous value. During this time, most dGH tests will not return reliable results. You have to try a dose, let it equilibrate with air overnight (or with an airstone), and then take your hardness measurement. 

If I've done my math right, it takes about 168 milligrams per gallon of the usual 30% HCl sold as muriatic acid to remove a degree of carbonate hardness. That's a little less than three tablespoons to neutralize a degree of carbonate hardness in a 100 gallon tank.

Bump: Adding HCl swaps chloride for bicarbonate on a one-for-one molar basis. Cl weighs 35 grams per mole versus 61 grams per mole for bicarbonate. You'll actually reduce the total dissolved solids on a mg/l basis. But remember that TDS is a rather fuzzy quantity, and what's usually measured on an electrical meter is moles of ions per liter which is then converted to mg/l on the display based on some assumptions the meter manufacturer made about the actual ionic makeup. Since it's a one-for-one swap on a molar basis, the measured value should be practically unchanged.


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## varanidguy (Sep 8, 2017)

kgbudge said:


> Maryland Guppy covered most of it, but:
> 
> HCl is dangerous only when concentrated. It leaves residual chloride, which is actually a minor plant nutrient. Very safe once diluted
> 
> ...


You, sir, are a gentleman and a scholar.


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## vvDO (Oct 18, 2010)

varanidguy said:


> Thank you for this thread. I may try experimenting with this myself. Have you taken note how much it raises TDS, if much at all?




TDS has been stable, checked last night after dosing micros and its right where it usually is, always increases with dosing ferts. I can check my holding tank to see if there’s a drop compared to tap.

My tap TDS usually 80-110 varies with season. Tank started off at 150 after W/C (Sat), as the week progresses usually ends up closer to 200. Last night it was 180.


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## jerrytheplater (Apr 11, 2007)

Store your HCl outside in a garage, not in your living space. It can fume and corrode your house and lungs. I use 20 degree Baume (about 31.5%) at work. When I open the storage tank on a humid day, the fumes will knock your socks off. I always stand upwind and the tank opening is only about 8".


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## varanidguy (Sep 8, 2017)

Say you want to remove enough KH to keep pH below 7.0 for the sake of micro nutrient uptake (iron, mainly), when you do water changes, do you add enough acid to treat the recorded amount of KH for the volume being changed or for the volume of the tank? Does adding it directly to a tank cause problems or should it be diluted first then added?


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## Maryland Guppy (Dec 6, 2014)

I've still failed to test the HCl in my 33G tank, the weekend is coming!>


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## vvDO (Oct 18, 2010)

varanidguy said:


> Say you want to remove enough KH to keep pH below 7.0 for the sake of micro nutrient uptake (iron, mainly), when you do water changes, do you add enough acid to treat the recorded amount of KH for the volume being changed or for the volume of the tank? Does adding it directly to a tank cause problems or should it be diluted first then added?




You will only want to treat the volume being changed and I would recommend treating it a while in advance or add a bubbler so you can off gas CO2. pH can drop significantly and you’ll get an increase in CO2.


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## Maryland Guppy (Dec 6, 2014)

Finally tested in the 33G tank.
Started @ 7dKH, strange it has been creeping up.

19.5ml brought it down to 1dKH.

Tested pH of degassed @ 7.08 and 2 hour into photoperiod @ 6.02
Did not monitor pH during the dosing.
Was in a hurry so maybe not all of the way de-gassed.
Doing another sample with airstone for more than 5 minutes now.

Bump: Finally tested in the 33G tank.
Started @ 7dKH, strange it has been creeping up.

19.5ml brought it down to 1dKH.

Tested pH of degassed @ 7.08 and 2 hour into photoperiod @ 6.02
Did not monitor pH during the dosing.
Was in a hurry so maybe not all of the way de-gassed.
Doing another sample with airstone for more than 5 minutes now.


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## Deanna (Feb 15, 2017)

WOW: I better NEVER see any proponents of this complain that glut is bad because it is used to kill germs in hospitals. I think that we should warn people that may read this thread, and then just throw it in their tanks, about the dangers. Muriatic acid is VERY caustic (30% HCL). It will corrode almost anything (including your clothes and skin), so don't put it in a container, other than what it came in, unless you really know what you are doing. It will also stain metal.

If you are going to use it, wear acid-resistant gloves and goggles and DO NOT breathe the fumes. If you want to really be be scared, do a search on what the vapors can do to your respiratory tract. If you spill any, hold your breath and run like hell ...or have a 50/50 mixture of baking soda and water standing by to 'douse' it. If handled properly and with protective gear, it can be used safely, but read-up on how to handle it.

Surely we can't be so desperate to lower KH that we are playing with this stuff so casually. A gallon of distilled water is about $1 and it will also permanently lower your KH. One muriatic acid spill and you'll wish that you had bought that RO unit.


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## Maryland Guppy (Dec 6, 2014)

Actually it's a bit more than 30%, not much but a bit more.
Maybe 31.5% or so. 20° baume on the scale.

It does require some care, used in pools, diluted for etching concrete surfaces etc... 
It is not for everyone by any means.

A better choice than nitric or sulfuric acid. >
Not caustic but acidic! :|


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## Immortal1 (Feb 18, 2015)

I will agree with @Deanna - not something for rookies to play around with. One thing I have learned... plastic syringes, like the 12ml medical grade "Normal Saline I.V. Flush Syringe" that I seem to have so many of, are very tolerant of the HCL. In my case, with some nitrile gloves, I can open the original container and fill the syringe with little threat of a spill. Then add how ever many ml are needed to the water. 

"Maybe 31.5% or so. 20° baume on the scale" - this is the same stuff I am using. And as Dianna stated, you really don't want to breath in any of the vapors.

Something I did note - the chemical reaction when adding HCL to tank water does lower your pH alot! In the interest of your fish I would not recommend dumping a bunch in a seeing what happens.
For my 75g tank, today I lowered the KH by 1 degree. 9ml seemed to do the job. I added the HCL a few drops at a time just above the spray bar. Yes you can smell it. Yes if you look close enough you can see a vapor. And yes, the ph does drop! In my case almost a full point. 

If you have fish I would strongly recommend *not* trying to drop the KH a lot all at once. I'm sure the chemists in this group could better explain the chemistry involved but it is my assumption that the drop in Ph is due to the rise in CO2 generated by the acid burning away at the Carbonite Hardness. Having air stones running during this process can help greatly to speed up burning off excess CO2, but I suspect it may not help enough if you were trying to drop the KH by say 5+ degrees.


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## cl3537 (Jan 28, 2019)

Immortal1 said:


> I will agree with @Deanna I'm sure the chemists in this group could better explain the chemistry involved but it is my assumption that the drop in Ph is due to the rise in CO2 generated by the acid burning away at the Carbonite Hardness.


You are removing a weak base Bicarbonate(HCO3-) from solution and lower pH. 
HCO3- + HCL ====> H2CO3 + Cl-
H2CO3 <=> H2O + CO2


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## Immortal1 (Feb 18, 2015)

cl3537 said:


> You are removing a weak base Bicarbonate(HCO3-) from solution and lower pH.
> HCO3- + HCL ====> H2CO3 + Cl-
> H2CO3 <=> H2O + CO2


 LOL, yeah, like that :grin2:
Chemistry was never my favorite subject in HS. Then again, I have fogotten a lot of what I did learn in HS over the last 36 years :surprise:


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## cl3537 (Jan 28, 2019)

Immortal1 said:


> LOL, yeah, like that :grin2:
> Chemistry was never my favorite subject in HS. Then again, I have fogotten a lot of what I did learn in HS over the last 36 years :surprise:


Sad to say after 8 years of research in Chemistry I have forgotten most of it as well.


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## Maryland Guppy (Dec 6, 2014)

cl3537 said:


> Sad to say after 8 years of research in Chemistry I have forgotten most of it as well.


I get this all too well.

Relearn enough to handle atomic weights and my own dosing spreadsheets.
And of course some of the long forgotten math involved!


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## Maryland Guppy (Dec 6, 2014)

A dying thread yet to be revived! :grin2:

Inert sub in the 80G was dosed for a 1dKH drop.
First time for HCl in this tank, dosed and it sticks!

The 33G with capped soil slowly creeps back up.
About .5dKH every week or two.

Note: an active substrate changes this game a little bit.


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## Maryland Guppy (Dec 6, 2014)

Warning: last attempt @ thread revival!

I have no updates other than an occasional bump to the capped soil tank.

Using only RODI I have to add a dash of alkalinity to the 80G.
This dash is only a .5dKH rise just to stay above zero.


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## varanidguy (Sep 8, 2017)

Maryland Guppy said:


> A dying thread yet to be revived! :grin2:
> 
> 
> 
> ...




I would think you’d wanna remove all dKH for an active substrate if it’s realistic/safe.


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## Maryland Guppy (Dec 6, 2014)

varanidguy said:


> I would think you’d wanna remove all dKH for an active substrate if it’s realistic/safe.


The main tank is 80G BDBS only.
My 33G gallon is capped soil so it creeps up slowly.
Extras go to the 33G unless they will survive the 75G low-tech.


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## SpringHalo (Oct 13, 2017)

I haven't tried this on my tanks yet since I couldn't find the right acid at my local hardware store, but I made a spreadsheet with calculations for how much to dose. It seems to roughly match what previous testers were working at, eg. 6ml per 20gal drops 2dKH -> 1.5ml per 10 gal per dKH. *My calculations are giving 1.35 mL per dKH per 10 gallons, or 0.36 mL per dKH per 10L, assuming 31% acid.* This is slightly more conservative, but should be more accurate assuming you can get precise hardness measurements (I get mine from the local water quality report which gives CaCO3 counts in PPM).

Here's the spreadsheet where you can enter your tank/WC water volume and get the required dosage. Use with caution and proper safety equipment.


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## Edward (Apr 11, 2005)

SpringHalo said:


> Here's the spreadsheet where you can enter your tank/WC water volume and get the required dosage. Use with caution and proper safety equipment.


SpringHalo, could you also add CaCl2 ppm addition?


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## Edward (Apr 11, 2005)

SpringHalo, that is very nice! Can you please add Cl2 ppm increase?

*1 dKH drop:*


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## Maryland Guppy (Dec 6, 2014)

Still dosing HCl to the capped soil tank.
KH still creeps up to 3dKH every couple weeks.
This has to level off soon I would imagine.


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## Edward (Apr 11, 2005)

Maryland Guppy said:


> Still dosing HCl to the capped soil tank.
> KH still creeps up to 3dKH every couple weeks.
> This has to level off soon I would imagine.


The increasing KH trend you see will not stop until there is HCO3 bicarbonate or CO3 carbonate present and acidic pH.


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## Maryland Guppy (Dec 6, 2014)

Edward said:


> The increasing KH trend you see will not stop until there is HCO3 bicarbonate or CO3 carbonate present and acidic pH.


Forced me to test my pH this eve, 6.20pH in that tank.


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## Deanna (Feb 15, 2017)

@Maryland Guppy,

I'm curious if you have calculated the accumulation of chloride that builds when you dose the HCl regularly, or is HCl dosing so infrequent as to make this a non-issue?


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## Edward (Apr 11, 2005)

Deanna said:


> @Maryland Guppy,
> 
> I'm curious if you have calculated the accumulation of chloride that builds when you dose the HCl regularly, or is HCl dosing so infrequent as to make this a non-issue?


 ... and also TDS ...


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## Maryland Guppy (Dec 6, 2014)

TDS is not over the top, 230 right now.

3-4ml HCl every month just to hover around 1dKH
It's a 33G, no phish, and about 7 gallon per week WC
Every month I do a 50% WC on this tank.
GH is at 8 now so I'm due for a WC now.


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## Edward (Apr 11, 2005)

Deanna said:


> @Maryland Guppy,
> 
> I'm curious if you have calculated the accumulation of chloride that builds when you dose the HCl regularly, or is HCl dosing so infrequent as to make this a non-issue?





Maryland Guppy said:


> TDS is not over the top, 230 right now.
> 
> 3-4ml HCl every month just to hover around 1dKH
> It's a 33G, no phish, and about 7 gallon per week WC
> ...


TDS 230 of what, ppm NaCl or µS? What value you had before using HCl? I think it will be difficult to decode with your leaching KH. 

It takes 3 - 4 ml of 31.45 % HCl into 33 gallon to lower KH from 1.7 – 1.9 to 1.0 degree, which adds 8.5 – 11.4 ppm Cl2 while ignoring the 20 % water changes. Makes sense? Question, wouldn’t be using diluted acid more “pleasant”?


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## Deanna (Feb 15, 2017)

Edward said:


> It takes 3 - 4 ml of 31.45 % HCl into 33 gallon to lower KH from 1.7 – 1.9 to 1.0 degree, which adds 8.5 – 11.4 ppm Cl2 while ignoring the 20 % water changes. Makes sense? Question, wouldn’t be using diluted acid more “pleasant”?


My understanding is that Cl > 7ppm is problematic for plants. So, with 50% monthly water changes, and assuming ~10ppm Cl added monthly (4 months), then there should be about 20ppm of Cl in the tank now and I don't think much Cl is consumed by plants. Am I being paranoid?


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## Maryland Guppy (Dec 6, 2014)

Edward said:


> TDS 230 of what, ppm NaCl or µS? What value you had before using HCl? I think it will be difficult to decode with your leaching KH.
> 
> It takes 3 - 4 ml of 31.45 % HCl into 33 gallon to lower KH from 1.7 – 1.9 to 1.0 degree, which adds 8.5 – 11.4 ppm Cl2 while ignoring the 20 % water changes. Makes sense? Question, wouldn’t be using diluted acid more “pleasant”?


ppm NaCl for TDS, values were about the same before dosing HCl.
Remember this is only 4ml every 4-6 weeks and it seems to be getting less as time goes on.

20° Baume is never pleasant! >>>

I am able to use pure R/O in this tank for WC's since GH & KH creep up but @ different rates.


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## Surf (Jun 13, 2017)

> My understanding is that Cl > 7ppm is problematic for plants. So, with 50% monthly water changes, and assuming ~10ppm Cl added monthly (4 months), then there should be about 20ppm of Cl in the tank now and I don't think much Cl is consumed by plants. Am I being paranoid?


When you add HCL it reacts with Calcium carbonate to form calcium chloride salt which is safe. Calcium chloride is used in some GH boosters. HCL is free chlorine and as a result it is very reacts and can kill fish, plants, bacteria and other plants. but slowly adding it to a tank or using small individual doses would probably be safe. The safest way to this would be to treat the tap water before adding it to the tank.

Note sulfuric acid would also have the same effect on KH by converting calcium carbonate to calcium sulfate.


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## cl3537 (Jan 28, 2019)

Surf said:


> When you add HCL it reacts with Calcium carbonate to form calcium chloride salt which is safe. Calcium chloride is used in some GH boosters. HCL is free chlorine and as a result it is very reacts and can kill fish, plants, bacteria and other plants. but slowly adding it to a tank or using small individual doses would probably be safe.


If Chloride is dangerous(?) source(?), than Chloride from HCl is just half as dangerous(only provides one Cl per molecule) as Chloride from CaCl2(two Cl- per molecule). In solution both are *fully hydrolized* and they don't exist as a salt, not in equilibrium, just simply not at all.

HCl is obviously more dangerous due to the H+ acidity not because of the Chloride.


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## Edward (Apr 11, 2005)

Deanna
Cl is an essential plant element and typical plants have the same amount in tissue as of Fe. When I mix CaSO4 and CaCl2 with RO I think I see better plants than with CaSO4 only. And, the most Cl2 I use is 80 ppm and plants look perfectly fine.


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## cl3537 (Jan 28, 2019)

Edward said:


> the most Cl2 I use is 80 ppm and plants look perfectly fine.


If you added 80ppm of Cl2(chlorine gas) I bet you would have problems for you, fish, and plants. >
If you add 80ppm of Cl- (chloride ions) than it is debateable whether that causes issues or not, it may not.


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## Deanna (Feb 15, 2017)

Edward said:


> Deanna
> Cl is an essential plant element and typical plants have the same amount in tissue as of Fe. When I mix CaSO4 and CaCl2 with RO I think I see better plants than with CaSO4 only. And, the most Cl2 I use is 80 ppm and plants look perfectly fine.


Yes, I've been doing the same: adding CaSO4 and CaCl, but only enough CaCl to deliver the ~7ppm so as not to exceed my [imagined?] upper limit of ~7ppm. I have, in my notes, that chloride starts to get toxic to plants above that level ...but you do well at an estimated 80ppm. Are you aware of any upper limit of Cl?


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## Edward (Apr 11, 2005)

Deanna said:


> Yes, I've been doing the same: adding CaSO4 and CaCl, but only enough CaCl to deliver the ~7ppm so as not to exceed my [imagined?] upper limit of ~7ppm. I have, in my notes, that chloride starts to get toxic to plants above that level ...but you do well at an estimated 80ppm. Are you aware of any upper limit of Cl?


Did you get this idea from some exaggerated brackish water research?


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## Deanna (Feb 15, 2017)

Edward said:


> Did you get this idea from some exaggerated brackish water research?


Don't recall the source (years ago), but it would have had to have been corroborated, which does not necessarily mean it was correct. Unless someone can support the toxicity issue, I'm going to abandon it.


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## Edward (Apr 11, 2005)

Low Na makes plants happy but higher makes them sick, so, so much for brackish research. The Cl is quite common in natural waters and plants need it. I know people who used RO with only CaCl2 as Ca source and it did work. I did it too. The only problem was the transition period in both directions.


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## Edward (Apr 11, 2005)

livingstone said:


> Does it make sense that the addition of small amounts (10-20 mL) of muriatic acid to my water raises the TDS somewhat significantly? Does it indicate the presence of something besides HCl in the muriatic acid solution?
> 
> Thanks,
> Dan


The addition of HCl increases chlorides and as a result also TDS. From my measurements I noticed TDS increase of 70 µS or 35 ppm NaCl after lowering KH from 5.0 to 1.5 dKH. Though, after 36 hours the total increase was 30 µS or 15 ppm NaCl2.


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