# Potassium chloride questions



## mgeorges (Feb 1, 2017)

I'm looking to change up my RODI remineralization to see if it resolves some stunting in plants I'm experiencing, and also to cut cost over the long run. I'll potentially be starting a separate thread on the stunting issue in a couple weeks after I see affects of new micros.

My current question is - my planned change is to start remineralizing GH with MgSO4 and CaSO4, and KH with NaHCO3. I would no longer have the chloride I'm getting from nilocg's reGen, so I was considering swapping K2SO4 in my regular EI dosing with KCl. To get the target 7.5ppm recommended by rotalabutterfly, I'd also be adding 2.63ppm Cl. I do not know the ppm of Cl I'm currently getting with reGen, but I'm wondering if there is an upper threshold for Cl?
@Greggz, burr told me you run RODI on your tanks. Maybe you'd have some idea on whether this is fine? Appreciate any input.


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## Greggz (May 19, 2008)

mgeorges said:


> I'm looking to change up my RODI remineralization to see if it resolves some stunting in plants I'm experiencing, and also to cut cost over the long run. I'll potentially be starting a separate thread on the stunting issue in a couple weeks after I see affects of new micros.
> 
> My current question is - my planned change is to start remineralizing GH with MgSO4 and CaSO4, and KH with NaHCO3. I would no longer have the chloride I'm getting from nilocg's reGen, so I was considering swapping K2SO4 in my regular EI dosing with KCl. To get the target 7.5ppm recommended by rotalabutterfly, I'd also be adding 2.63ppm Cl. I do not know the ppm of Cl I'm currently getting with reGen, but I'm wondering if there is an upper threshold for Cl?
> 
> @Greggz, burr told me you run RODI on your tanks. Maybe you'd have some idea on whether this is fine? Appreciate any input.


Yes I use 100% RO water (no DI).

I use MgSO4, CaSO4, and K2CO3 to remineralize. 

I've never dosed CL. I'm not sure why you think you need to???


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## mgeorges (Feb 1, 2017)

Greggz said:


> Yes I use 100% RO water (no DI).
> 
> I use MgSO4, CaSO4, and K2CO3 to remineralize.
> 
> I've never dosed CL. I'm not sure why you think you need to???


I keep hearing the importance of chloride, I'm using RODI so there's nothing in that water.


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## Quagulator (May 4, 2015)

mgeorges said:


> I keep hearing the importance of chloride, I'm using RODI so there's nothing in that water.


Grab some potash, push a few granules into the substrate, enough Cl will leach out over time...


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## Surf (Jun 13, 2017)

Chlorine is a essential plant nutrient and plants like about as much Cl as iron. That means in most cases you only need between 0.04 and 0.1 ppm of Cl. Since RO systems remove chlorine and chlorides from the water, fish food and the substrate will be the only source in a tank. That may or may not be enough in some tanks. So to be sure you have it I feel it should be added. It is apparently used by plants to help move nutrients to were they are need in the plant. Some people use Chloride GH boosters and 1degree of that can push chloride lives of about 30ppm per degree of GH. Which is a lot higher than what we are talking about here. So high doses of Chloride are safe. but there is no reason to push it that high in this case.

In Rotalabutterfly.com. you are probably selecting "estimative index" for the "I am dosing for" setting. Instead select the dose to reach a target. If you do that and put 1ppm in it will calculate how much should be added to reach 1ppm of K (no way to change that) and for Cl it says you get 035ppm Cl. you adjust target in the calculator to get 1ppm Cl for your tank. I think 1ppm should be all you need to insure CL is adequate.

I believe the EI calls for K2SO4 to insure adequate sulfur is present in the tank (sulfur is another plant nutrient). If you are dosing potassium nitrate and potassium phosphate for NPK you already should have more potassium than plants needed. The calcium and magnesium sulfate will supply all the needed Ca, Mg, and S plants need

Chlorine is a essential plant nutrient and plants like about as much Cl as iron. That means in most cases you only need between 0.04 and 0.1 ppm of Cl. Since RO systems remove chlorine and chlorides from the water, fish food and the substrate will be the only source in a tank. That may or may not be enough in some tanks. So to be sure you have it I feel it should be added. It is apparently used by plants to help move nutrients to were they are need in the plant. Some people use Chloride GH boosters and 1degree of that can push chloride lives of about 30ppm per degree of GH. Which is a lot higher than what we are talking about here. So high doses of Chloride are safe. but there is no reason to push it that high in this case.

In Rotalabutterfly.com. you are probably selecting "estimative index" for the "I am dosing for" setting. Instead select the dose to reach a target. If you do that and put 1ppm in it will calculate how much should be added to reach 1ppm of K (no way to change that) and for Cl it says you get 035ppm Cl. you adjust target in the calculator to get 1ppm Cl for your tank. I think 1ppm should be all you need to insure CL is adequate.

I believe the EI calls for K2SO4 to insure adequate sulfur is present in the tank (sulfur is another plant nutrient). If you are dosing potassium nitrate and potassium phosphate for NPK you already should have more potassium than plants needed. The calcium and magnesium sulfate will supply all the needed Ca, Mg, and S plants need


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## mgeorges (Feb 1, 2017)

Quagulator said:


> Grab some potash, push a few granules into the substrate, enough Cl will leach out over time...


Interesting. I've got root tabs, Osmocote +, a bunch of them in my 29 gal and I know they contain potash. You believe that would be enough Cl to take care of plants?


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## Quagulator (May 4, 2015)

mgeorges said:


> Interesting. I've got root tabs, Osmocote +, a bunch of them in my 29 gal and I know they contain potash. You believe that would be enough Cl to take care of plants?


Should be plenty, you'll get some Cl from other sources like food too. 

potash is KCl after all


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## Greggz (May 19, 2008)

mgeorges said:


> I keep hearing the importance of chloride, I'm using RODI so there's nothing in that water.


Curious where you keep hearing that? 

I follow quite a few very successful plant keepers. And by that I mean people where I have seen many pictures of their tank, enough so that I feel that I can learn from their experience. 

And I have never really heard it mentioned. Not saying it can't help. But would really be curious as to who is mentioning this and where.

I mean if it would really help, I would consider dosing it myself.


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## mgeorges (Feb 1, 2017)

Quagulator said:


> Should be plenty, you'll get some Cl from other sources like food too.
> 
> potash is KCl after all


No, Osmocote's potash is K2O, potassium oxide. Potash can be several different potassium salts apparently, so my Osmocote isn't going to add any Cl.
@Greggz, I've seen it mentioned several times in the micros thread. I've also seen quite a few discussions on here about the importance of it in the aquarium. I was under the impression that Cl was an essential element for plants.


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## Quagulator (May 4, 2015)

mgeorges said:


> No, Osmocote's potash is K2O, potassium oxide. Potash can be several different potassium salts apparently, so my Osmocote isn't going to add any Cl.
> @Greggz, I've seen it mentioned several times in the micros thread. I've also seen quite a few discussions on here about the importance of it in the aquarium. I was under the impression that Cl was an essential element for plants.


Ah, Yes I see now... I was on thier website and they don't list Cl anywhere.... Too bad you weren't closer to me, I would ship you some for free


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## Greggz (May 19, 2008)

mgeorges said:


> @Greggz, I've seen it mentioned several times in the micros thread. I've also seen quite a few discussions on here about the importance of it in the aquarium.


Well I'll have to go back through the thread and see who mentions it, as I always try and consider the source. Who knows, maybe there is something to learn there. 

But in general, keep in mind there are loads of things more important than dosing to specific numbers. 

In my opinion, concentrate on the basics first (light, CO2, tank maintenance, etc.), then fool around with fine tuning ferts. There isn't any magic formula that will work if you don't get the rest right first.


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## mgeorges (Feb 1, 2017)

Quagulator said:


> Ah, Yes I see now... I was on thier website and they don't list Cl anywhere.... Too bad you weren't closer to me, I would ship you some for free


Appreciate that, no worries though. Cl is pretty cheap


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## Chlorophile (Aug 2, 2011)

The top 4 or 5 ingredients in Seachem Flourish are chloride based fertilizers so I've added a small dose of Flourish once a week to the tank to hopefully cover CL since its not in anything else I'm adding other than fish food, and I dislike the lack of predictability in expecting fish food to act as fertilizer when I have so few small fish.


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## happi (Dec 18, 2009)

you could add KHCO3, CaSo4, CaCl, MgSO4 for better combo, try to keep the Cl less than 5 ppm during water changes.


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## mgeorges (Feb 1, 2017)

I may just dose 110mg NaCl(table salt) into my 29gal to get ~0.61ppm Cl and call it a day. Would give me ~0.39ppm sodium, pretty insignificant, not enough salt to mess any of my fish or shrimp up. Anyone see a problem with this?

I could do 200mg and get 1.11ppm Cl and 0.72ppm Na...


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## aquazone (Jul 9, 2003)

I've tested my tank water for years via ion chromotography. I dose with CaCl and KCl to get the Ca and K I need. Rarely do I use KNO3, as my nitrates range from 5-15 ppm. My tank's water runs around 80-100 ppm Cl and 150-200 ppm SO4. The vast amjority of the SO4 comes from MgSO4 Epsom salt. SO4 in my tap water is around 30 ppm and Cl is around 35 ppm. All plants seem pretty happy.


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## happi (Dec 18, 2009)

@mgeorges, i would skip the Nacl and K2CO3, i didn't have the best experience with K2Co3. try this one and see how it works out for you

30 gallon water 

Add 4.05 grams KHCO3
Add 7.31 grams CaSO4.2H2O
Add 1.25 grams CaCl2.2H2O
Add 5.75 grams MgSO4.7H2O
Add 0.442 grams NaHCO3

Ca	18
Mg	5
K	13.93
Cl	5.31
S	18.6 (55 ppm SO4)
Na	1
dGH	3.68
dKH	1.13

Bump:


aquazone said:


> I've tested my tank water for years via ion chromotography. I dose with CaCl and KCl to get the Ca and K I need. Rarely do I use KNO3, as my nitrates range from 5-15 ppm. My tank's water runs around 80-100 ppm Cl and 150-200 ppm SO4. The vast amjority of the SO4 comes from MgSO4 Epsom salt. SO4 in my tap water is around 30 ppm and Cl is around 35 ppm. All plants seem pretty happy.


hi there, can you shine some lights on uptake of Cl and So4 in our tanks if you did test this? how much did you add and how much is left in the tank say for few weeks without adding more or changing water? if you could provide more info as well.


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## mgeorges (Feb 1, 2017)

@happi What kind of issues were you having with K2CO3? I was actually looking a potassium carbonate vs bicarbonate...looks like they both do the job of raising KH. Is there an advantage to one vs the other? Also, will that low of a KH keep things stable enough in a tank getting injected CO2? I can't have big swings, I'll be keeping Sakura fire red cherries and C. habrosus in a 10 gal, and then some similarly sensitive livestock in a 29. 
This means I've gotta buy more compounds lol...do you have a scale that actually measures to that many decimal points? I think mine only does to .0 unfortunately. I'd be dosing this into 5 gallon buckets before adding to my tanks.

@Greggz Have you used both of these compounds for KH, did you have a preference?

I was reading that K2CO3 created a strong alkaline solution which was my only concern, whereas KHCO3 stays pretty neutral. Perhaps with how little of the salt is actually being added, it's insignificant?

Edit - Dosing KNO3 and KH2PO4 and potentially KCl to replace K2S04(since remineralizing with MgSO4 and CaSO4 will provide plenty of S), I should be getting plenty of K. I'm thinking I'll just use NaHCO3 for KH for the simple fact that I've got 20lbs of the stuff.


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## FreshPuff (Oct 31, 2011)

happi said:


> @mgeorges, i would skip the Nacl and K2CO3, i didn't have the best experience with K2Co3.


Happi, could you please elaborate on the issues you saw with K2CO3? And what do you recommend instead?


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## Surf (Jun 13, 2017)

I don't know what issues Happy saw. But earlier this year there was a post about snails dying in a tank. The person that stated the thread found that switching fr KHCO3 to NaHCO3 for KH did resolve the snail deaths. Most plants don't need sodium. However animals do need sodium as well as potassium. So a balance of sodium and potassium is probably Best. As to the PH affects I would expect K2 CO2 and KHCO2 would be similar to NA2CO3 and NaHCO3


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## happi (Dec 18, 2009)

FreshPuff said:


> Happi, could you please elaborate on the issues you saw with K2CO3? And what do you recommend instead?


K2co3, in my case it would kill fishes and certain plant Sp. most of my soft water plant would randomly melt from certain part of the plant, issue was resolved once i switched to KHCo3.


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## FreshPuff (Oct 31, 2011)

Surf said:


> I don't know what issues Happy saw. But earlier this year there was a post about snails dying in a tank. The person that stated the thread found that switching fr KHCO3 to NaHCO3 for KH did resolve the snail deaths. Most plants don't need sodium. However animals do need sodium as well as potassium. So a balance of sodium and potassium is probably Best. As to the PH affects I would expect K2 CO2 and KHCO2 would be similar to NA2CO3 and NaHCO3


I use rodi water and I am pretty strict with my ferts. I just realized I have no real source of Na in my tank other than the few grams of seachem alkaline buffer I use at water change. hmmmm. Something I totally overlooked. Thanks!



happi said:


> K2co3, in my case it would kill fishes and certain plant Sp. most of my soft water plant would randomly melt from certain part of the plant, issue was resolved once i switched to KHCo3.


Thats interesting... Right when I'm about to stop using Seachem alkaline buffer and begin using K2CO3 to raise the dKH in rodi water I read this. Darn. You are making rethink things!!!


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## mgeorges (Feb 1, 2017)

Surf said:


> I don't know what issues Happy saw. But earlier this year there was a post about snails dying in a tank. The person that stated the thread found that switching fr KHCO3 to NaHCO3 for KH did resolve the snail deaths. Most plants don't need sodium. However animals do need sodium as well as potassium. So a balance of sodium and potassium is probably Best. As to the PH affects I would expect K2 CO2 and KHCO2 would be similar to NA2CO3 and NaHCO3


That person was me.

In my shrimp tank, I started using the ratio discussed below, switching from pure NaHCO3 buffering. I buffer to 4 dKH, so 2dKH from NaHCO3 and 2dKH from KHCO3. Within a few weeks, my MTS population stopped reproducing, started dying, and my shrimp population has begun to decline severely as well. To add insult to injury, my Blyxa that had been doing WONDERFULLY before the switch melted to the point I was only able to recover a few stems. Broke my lil heart. Blyxa melt could've been my fault - more of something should've been added with the generous uptick in K...not sure.

My struggles seem unique, I've not found others who share my problems with inverts and K. So take my findings with a grain of salt. 



FreshPuff said:


> Thats interesting... Right when I'm about to stop using Seachem alkaline buffer and begin using K2CO3 to raise the dKH in rodi water I read this. Darn. You are making rethink things!!!


I have started using KHCO3 and NaHCO3 in a 1/2 & 1/2 ratio to buffer KH. So if I want a dKH of 2, I check rotalabutterfly to figure out how much KHCO3 I need to reach 1dKH and how much NaHCO3 I need to reach 1dKH. I also add in a dash of KCl at water change.


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