Aquaponic Gardening

A Community and Forum For Aquaponic Gardeners

I have been looking for a safe chemical to lift my alkalinity above rain water levels (need too much lime for this).  I have narrowed the list down to sodium and potassium bicarbonate.  I do not need a lot (a cup or so) but still do not like sodium products.  I therefore want to go with potassium bicarb.  Anyone used it before or know of potential problems brewing?  I do not want to use it constantly in my system - but add it to my rain tanks to get the alkalinity right before I use it in my AP system.

Views: 436

Reply to This

Replies to This Discussion

potassium bicarbonate is actually a recommended way for buffering pH.

No problems brewing, most people get it from a brewing supply place actually.


I've never used it personally.  I've got plenty of shells and lime available to buffer my system easily so I generally need to add the seaweed extract to get my trace elements plus potassium.

I've got some on order.  I thought I'd try it, but I do use a lot of KOH when l want to ease off the hydrated lime or get more results than dolomitic lime.  Thanks for the tip on where to get it TC.  I'll send my brewer buddy to pick some up next time he goes on a supply run. 

It also makes a pretty good foliar spray for powdery mildew...


I use it to not only buffer, but to provide a potassium boost when plants are at the flowering/fruiting/seeding stage...


Otherwise, if I need to pull the pH back I use Calcium Hydroxide... mainly because it's so readily, and cheaply, available compared to Potassium Hydroxide...


Calcium Hydroxide is often known as "slaked",, or "hydrated" lime.... commonly used by brickies...

Thanks for the reassurances.  I have little trouble finding stuff like this - brother in a biochem lab and a good chem supply store in town.  Will see if I can get the system alkalinity back to where it was before I switched to rain water.
Some wonderful tips in here - thank you.  I hope you guys don't mind but when you come up with these gems - like finding potassium carbonate at a brewers supply store and that it also works as a foliar spray for powdery mildew - I'm adding them into my book.  You will definitely be thanked in the Acknowledgements section!

It's actually marketed here in Australia as an approved "organic" fungacide... EcoRose...

Oh, I know this stuff is all public domain but I just wanted to let you guys know that I appreciate having it all here in one place.  I had 4 months to write this book and it has really helped to have so much info right here.  
I'm still hunting for eco rose or potassium bicarb.  In the mean time, I've got some potassium carbonate, but it does not seem to have a huge effect on alkalinity.  30 g in 160 liters of water only changed the alkalinity up to between 50 and 60.  I'm worried about the amount of potassium that will end up in my system over time if I try to get the whole system up to 140.  Anyone have experience with how much you can add potassium before it goes toxic?
If you're trying to raise hardness, rather than pH... and worried about toxicity... then go for Calcium Carbonate...

Reply to Discussion


© 2022   Created by Sylvia Bernstein.   Powered by

Badges  |  Report an Issue  |  Terms of Service