Help With Buffers....

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devan221

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So.....I think I need to use a buffer of some sort. I have 3 tanks. 2 have shrimp and fish. The other has dwarf crayfish and fish. I understand that my kh needs to be 3-5. To get my kh to 5 with Eqilibrium in one of my tanks, my gh was 28. Yes, 28. That is obviously not good. So.....Can someone explain to this lawyer (not chemist) what buffers do and which one I can use to up the kh without upping either ph or gh? Fyi.....ph is 7.6. And I only use RO water. Don't know how that happens, but would love to understand. Every time I think I understand, someone says something contrary to what I thought was correct. Thanks for the help!
 

CraniumRex

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Hi - the best explanation I ever read for the relationship between KH (temporary hardness) GH (permanent hardness) and pH was on this thread : Important - Understanding pH, KH, GH in Home Aqauriums

I’m not a chemist either but have done some reading on this subject - still learning but from what I understand, it’s hard to increase hardness and KH - which is the stuff that buffers your water from increasing acidity (pH crashing too low or swinging up and down) and keeps your pH stable, without increasing pH to some extent. I don’t know much about shrimp but understand they do need some hardness in the water for their exoskeletons. My pH is 7.8 out of the tap and 8.2 in my tanks. May I ask what concern you have with the water - specifically the GH?

Is the GH measurement of the water you are adding or the tank? Many things can up your GH - do you have anything in your tanks like coral or crushed shells as well?

Edited to add: are your KH and GH expressed in mg/L or ppm or in degrees?

I gather you are inquiring about a buffering agent, duh me, sorry. No experience with RO water or adding things but in passing have read about seachem acid and alkaline buffers. The acid isn’t really a buffer, just lowers your pH while the alkaline maintains your KH to keep the pH stable. That exhausts my very limited knowledge!
 
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GlassyD

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Equilibrium is almost entirely GH, as you have discovered. To raise KH (buffer) without also raising GH you need a bicarbonate of either sodium or potassium. Baking soda, or Seachem Alkaline Buffer, will increase KH. To raise both GH and KH in equal measures, use calcium carbonate in all its various forms... crushed coral, aragonite, etc.



It is very common for people to want more buffer (KH) while wanting at the same time to have the pH stay low, but its not realistic. All else being equal, pH will always increase along with an increase in KH (unless you inject CO2, or use organic acids). The best approach is to find sufficient KH that works for your tank and water change routine, and let the pH be wherever it ends up. You can have KH=0 with a low pH and change some water every day to keep the pH from falling down, but that isn't practical for very many people.
 
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