# The terrible tragedy of pH, KH, and GH



## Gnomecatcher (Sep 8, 2011)

Enter penniless, jobless college chemistry student.

I have a 10 gallon, money eating disaster that had an extremely low pH, so much so that I had NO biological activity. My ammonium was off the API test kit scale, 0 nitrites, 0 nitrates, and the pH was, I presume, below 6, but I had no way to know because my test kit doesn't read that low. It is about 5 months old, but it seems the honeymoon is over, and has been on a downhill run ever since. My plants used to have incredible growth, but then all but the hardiest committed suicide.

Fish were dying.

I had insomnia.

I didn't eat for weeks.

You can tell I have absolutely no idea what I am doing.

The water from my tap, after it's been treated and aged for a week, has a KH of practically 0, and a pH of about 8.2-4 ish. Overall my tap is extremely soft, almost as if it's been run through a peat moss filter, but I don't know the exact GH because I don't have anything to test that.

Today I added Seachem Alkaline and Acid buffer because I read that KH was an indication of your water's buffering capacity. Which makes sense to me and what little of my education that my brain has retained, because your body uses bicarbonate to buffer the pH of your blood from the effects of carbonic acid. My KH is now at about 100 ppm and the pH is at 7.3/4 ish.

So here are some questions:

1. Is my water okay now?

2. While I was reading a couple of forum arguments, some people said that KH has nothing to do with buffering? Are my professors wrong, or do these forum people have it wrong?

3. I also read some very frisky forum people arguing (on more than one forum) about using Seachem Alkaline buffer vs. adding baking soda (both are sodium bicarbonate, NaHCO3). If they are both pretty much the same, why would you choose one over the other?

4. Also I read that you can raise the KH without raising the GH. So let's say I add baking soda, would that raise the GH?

5. For certain species that are sensitive to GH and require soft water (I know most species are adaptable, but let's just say there is a fish that ABSOLUTELY MUST HAVE soft water), would raising the KH have a negative effect on them?

6. Is there something lacking in my soft water that my plants need that caused them to die? Should I dose with something? I currently have Flourish, Flourish Excel (which I use instead of CO2 injection because I have no money), and API Leaf Zone.

7. Any other tips to prevent the Aqua-apocalypse?


Sorry about the long post. These questions are long overdue. If you made it this far, you must be married or are Superman/woman.


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## Jeffww (Aug 6, 2010)

Let's slow down first. Can you tell us more about the set up? What substrate do you have? CO2? Lighting? Fish you had/plan on having in the future. What do you do with with the tap water after you age it.? 


GH is a measure of Ca and Mg and some other metals that are so trace they don't really affect the measurement. KH is carbonate hardness that measures the amount of HCO3-/CO3 -- in the water wheter it's from H2CO3 dissolution or CaCO3 dissolving. In other words you can have more KH with sodium bicarb. I think (requires serious fact checking) that bicarb will stabilize pH at like 8.1 (??) pH. As for how much you add you can look it up I've never done it before. 


A few guidelines: 
Don't fiddle with your water using chemicals unless you already know its stable condition and only do so outside of the tank and monitor said conditions frequently. 

I'm assuming you'll have access to accurate/callibrated pH probes at school. Just bring in some water when you're at lab and test it that'll give you a baseline pH. Remember to let it age for awhile to let it off gas some co2.
*
Also look into fishless cycling*. Normally KH is an unimportant reading...Also hunt around the lab for other stuff like a conductivity meter...that should give you a very rough estimate of ions in your water. 

What filter are you running btw? Any information helps. 

To answer some questions: 
1. Your water is probably _not_ okay. Your tank is less ready for fish if it's uncycled. 
2.KH DOES have to do with the H2CO3 <--> HCO3- + H+ buffering system. You should know this! 
3. Don't bother with anything other than seachem RO right or GH buffer (whatever they call it these days). If you're not above pilfering from the lab you can make your own with CaCl or CaSO4, MgSO4 and K2SO4 and KCL although these things are literally available in your grocery store. 
5. Raising KH _generally_ not considered wise since the methods prescribed not using carbonic acid (co2 injection) will raise pH through offsetting chemical equillibria away from the formation H+. 

Without more info I can't tell you about the plants.


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## wkndracer (Mar 14, 2009)

Jeffww with 1dKH or more it's an unimportant reading. 0.0dKH is a problem. 
OP, testing 8.2 out of your tap with no KH is an odd reading. Is this after it sits in a open container overnight?

Baking soda raises TDS and KH only without effect to GH.


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## Jeffww (Aug 6, 2010)

wkndracer said:


> Jeffww with 1dKH or more it's an unimportant reading. 0.0dKH is a problem.
> OP, testing 8.2 out of your tap with no KH is an odd reading. Is this after it sits in a open container overnight?
> 
> Baking soda raises TDS and KH only without effect to GH.


There are plenty of people with 0KH out there that operate fine. for one the titration test for it is pretty inaccurate and 0 is probably .25 degrees which is still buffering. It's also important to note there are other buffers in the water not just carbonate. So KH can't really give a full picture. It's why the pH - KH - CO2 relationship doesn't work.


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## Gnomecatcher (Sep 8, 2011)

Okay okay. *deep breath* o___o

The set up:
- 10 gallons
- Substrate: Caribsea Tahitian black sand (haha, don't choke)
- No CO2 anymore, but I did a DIY yeast setup in the past
- Fish I had: guppies, neon tetras, and mutant female bettas that have survived the worst conditions imaginable
- Fish I have: neon tetras and mutant bettas
- Lighting: 2 cheap 25watt incandescents that came with the hood. I have a Marineland double bright LED fixture coming in the mail soon.
- Filter: Tetra Whisper PF10 (dear god...but I really want an Eheim canister)


What do you mean fiddling with the water outside of the tank? Does a bucket work?

Fishless cycling? There are still fishies.  Maybe on my new tank... How long does that usually take?

Yes, I can probably use the school equipment. And I can probably pilfer.

My tank used to be beautifully cycled, how come it's "uncycled" now? Do you think maybe my plants could have died because nitrate was no longer being produced? I had wisteria, ludwigia, moneywort, pennywort, baby tears, and java fern. All that's left is java fern, penny wort, and baby tears.

Yes I know KH relates to the buffering system. But I heard something different and I doubted! But shhh don't tell the prof., or he'll send me back to first year chem.

I don't need the RO additives if I'm using tap, do I?

Can you also explain further about your answer to number 5.

THANKS!


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## wkndracer (Mar 14, 2009)

ok then, the little tank here that tested 0.0dKH and the pH crashed on must have been a mistake or myth sorry to waste the bandwidth

didn't see anything in the OP's post regarding injection so why the pH, KH, CO2 relationship factors into this response must be for conversation purposes

if I don't test at least 2dKH on my tanks I'm adjusting the water
RO water here has been buffered with baking soda for 3 years without livestock or plant issues

good luck OP, hope you figure out the issue


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## Gnomecatcher (Sep 8, 2011)

wkndracer said:


> Jeffww with 1dKH or more it's an unimportant reading. 0.0dKH is a problem.
> OP, testing 8.2 out of your tap with no KH is an odd reading. Is this after it sits in a open container overnight?
> 
> Baking soda raises TDS and KH only without effect to GH.



Yes, it sits in an open top bucket for a week before I use it.

Jeffww, the titration solution is really concentrated it seems. From 0 - 1 dKH it goes from 0 to 17.9 ppm.


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## Gnomecatcher (Sep 8, 2011)

wkndracer said:


> ok then, the little tank here that tested 0.0dKH and the pH crashed on must have been a mistake or myth sorry to waste the bandwidth
> 
> didn't see anything in the OP's post regarding injection so why the pH, KH, CO2 relationship factors into this response must be for conversation purposes
> 
> ...


Do you use anything else in your RO water besides baking soda?


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## Jeffww (Aug 6, 2010)

wkndracer said:


> ok then, the little tank here that tested 0.0dKH and the pH crashed on must have been a mistake or myth sorry to waste the bandwidth
> 
> didn't see anything in the OP's post regarding injection so why the pH, KH, CO2 relationship factors into this response must be for conversation purposes
> 
> ...



I was simple addressing the fact that there are other buffering compounds in fish water. KH only measures one buffering system with carbonate there are multitudes of them. Just because KH is 0 doesn't mean the water is necessarily unstable. 

Now in his case the 0KH may be disconcerting as he experienced pH crash but it's also important not to bluntly state 0KH = bad since there are a multitude of cases where 0KH is just fine. 

As for the OP. You know when this started happening? Or if you did anything different than usual? It could have been easily a lack of carbonate but the 0kH and 8+ pH present makes me wonder.... Yah a bucket would be fine. Treat it as you would preparing a buffering solution in the lab. Mix outside and incrementally. 

I think after re-reading you may have experienced pH crash from lack of buffering so yah...bicarb would be a good idea. API also makes a GH titration you could check out. Your water is wonky. But it can't be that bad since there are tons of people from your area that have healthy tanks...


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## wkndracer (Mar 14, 2009)

Gnomecatcher said:


> Do you use anything else in your RO water besides baking soda?


(site sponsor) GLA - Ultimate GH Booster. Very similar to Seachem's Equilibrium only the grind is much finer and I have less issues with it clumping in the storage bag and mixing into the tank is much easier. 
Effects the water the same with 16grams/20gal. testing to about 3dGH.

Arm&Hammer baking soda is the brand used.
To increase KH
leveled spoons
1/8 TSP : 6.5 gallons = 1dKH
1/4 TSP : 13 gallons = 1dKH
1/2 TSP : 26 gallons = 1dKH
API KH kit used for testing and the results have been range accurate since I started using BS >3years ago.

(imo) both of these are very cost effective long term also

HTH


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## Jeffww (Aug 6, 2010)

GH booster = like 3: 3: 1 potassium sulfate, Calcium sulfate and like magnesium sulfate. By (volume?) you can mix it up in a split.


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## Gnomecatcher (Sep 8, 2011)

Actually I am a she. 



Jeffww said:


> I was simple addressing the fact that there are other buffering compounds in fish water. KH only measures one buffering system with carbonate there are multitudes of them. Just because KH is 0 doesn't mean the water is necessarily unstable.


Correct.




Jeffww said:


> As for the OP. You know when this started happening? Or if you did anything different than usual? It could have been easily a lack of carbonate but the 0kH and 8+ pH present makes me wonder.... Yah a bucket would be fine. Treat it as you would preparing a buffering solution in the lab. Mix outside and incrementally.


I noticed my pH crash when I started using CO2 injection from a DIY yeast bottle. But then again, before I started injecting, I never really monitored my water that carefully. Mostly because I was clueless.
^Reread. Out of context, it sounds like something a druggie would say.

There is a guy in my neighborhood that raises discus. I imagine it is my wonderful soft water?

wkndracer: I'll look into it. Thanks for the tip.


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## Gnomecatcher (Sep 8, 2011)

Jeffww said:


> GH booster = like 3: 3: 1 potassium sulfate, Calcium sulfate and like magnesium sulfate. By (volume?) you can mix it up in a split.


I think I might be able to get them dry. Better do weight, to avoid the stoichiometry.


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## Jeffww (Aug 6, 2010)

Gnomecatcher said:


> Actually I am a she.
> 
> 
> 
> ...


Well there you have it. I think. Your soft water lacked carbonate to counteract the influx of CO2 which formed H+ freely (there was no carbonate to temper the conversion), rapidly acidifying the water and killing your bacteria. 

Don't worry about using moles and don't worry about making them anhydrous/massing them. That'll take forever. I believe I learned from Tom Barr that the GH that bears his name (that he doesn't make, comically) is made through volume not mass.


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## Gnomecatcher (Sep 8, 2011)

I will never graduate with that kind of advice. But this is fish, so I suppose it's okay.

So what about my plants? Will a daily fert like Flourish do the trick?

And the rest of my fish won't die as I start to recycle the tank, will they? They survived the first cycling.


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## Jeffww (Aug 6, 2010)

Gnomecatcher said:


> I will never graduate with that kind of advice. But this is fish, so I suppose it's okay.
> 
> So what about my plants? Will a daily fert like Flourish do the trick?
> 
> And the rest of my fish won't die as I start to recycle the tank, will they? They survived the first cycling.


Lol. My old chem teacher told me in organo "measuring" was "A scoop of this" and then seeing if it changed and if it didn't you'd add more. 

They should be fine. As for plants they should be okay depending on what species you have. CO2 is always good but now we know that your water needs to be buffered before usage. I'd say try it out with your new light _+ co2 then if you see algae/deficiencies consider some fertilization like basic macros NPK and some flourish trace...


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## Gnomecatcher (Sep 8, 2011)

Okay, will do.

Whew. What a headache.

Thanks a ton!


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## Coursair (Apr 16, 2011)

A cheap solution for lighting for now would be to use screw in compact fluorescents. 

Why do you leave the water out for a week ?? Since you are using a conditioner there is no need for this AFAIK. 24 hours perhaps. 

Perhaps your plants died from lack of proper lighting ? Sorry to hear about your issues. 

My newest tank is sand substrate. I just seeded it with gel caps with Osmocote. So far the plants seem fine. 

I'm completely clueless about your water chemistry. 

GL


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