pH up

[Courtney Edwards]

To all the budding chemists out there, I have a question: 

I'm trying to raise my pH and I'm struggling with garbled information, and poorly labeled products.

I get that the standard choice for changing pH is calcium and potassium hydroxide, but I figure that I will probably start a crazy swinging pH routine that I would rather avoid. I like the idea of slow and stable, my plants, fish, and I aren't in a rush, balance would be nice.  

I would like to use calcium carbonate (smashed up oyster shells, no problem there) and potassium bicarbonate. But I can't seem to find a source for the potassium (nothing at the brewing places, and no organic powdery mildew control products in the stores).  

So I went to my local hydroponics store and bought some General Hydro pH up. I got the powder version. It says it contains potassium carbonate and potassium citrate. This is supposedly the same product that is in the Aquaponicstore, but not a liquid.

On the aquaponics website it says that the liquid is potassium carbonate and potassium hydroxide, but the liquid label on the GenHydro website says its potassium carbonate and potassium silicate. The GenHydro website doesn't list ingredients for the powder, I only have it from the container I bought.

 

So the questions are:

can I use the GenHydro powder pH up in my system? 

what's the deal with potassium citrate? 

what about potassium silicate?

 

thanks. 

 

  

[Jesse Hull]

Too much of a good thing is not a good thing, and water chemistry isn't just about NH3/NH4, NO3, NO2 and pH levels.  Potassium and calcium test kits are available, so even if you're using R/O filtered water, I do not just blindly alternate b/t potassium and calcium buffers.  Test for it the same way you would if you were running a commercial hydroponic system.

A current consulting project Molly and I have been working on revealed that their system had high enough levels of calcium from the source water.  This doesn't mean that calcium will never need to be added, but it should be checked to make sure before additions are made.

If you're doing regular water changes, then you probably won't end up with a problem.  However, if you're only 'topping off', then minerals will build up in the system and can eventually become out of balance.  It's actually quite easy to overdose on anything that is being regularly added, especially if it's already there to begin with in your source water.  When a toxicity occurs it's hard to recover, especially on a commercial level, testing will make sure this doesn't happen.

What many people have learned one way or another is that an aquaponics system is incredibly resilient once it's properly mature.  And fish, especially tilapia, can build up a tolerance for many things.

But just because things are surviving doesn't mean they're thriving.

TCLynx said:

Yea, read the labels of products before you use them.

I think gen hydro's pH Down product some one once used not only contained citric acid but also ammonia so while the poor new system was suffering from high pH the person was not only using a product that inhibited their bacteria colony forming but also was spiking the ammonia off the charts without realizing it.

So Jesse, how might people recognize if potassium is what they need or if it might be detrimental?