Aquaponic Gardening

A Community and Forum For Aquaponic Gardeners

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?





Views: 1330

Reply to This

Replies to This Discussion

You should be able to order potassium bicarbonate on Amazon and probably from other sources online if you want to avoid paying the price for the hydro products.

That General Hydroponics product with the potassium bicarb and potassium citrate seems safe enough at a glance though.

Ah... Seachem Neutral Regulator.... the complete miracle bottle of snake oil....


Doesn't explain how it manages to buffer pH up... and/or down... all in one bottle......


But does claim to do so many other, some near impossible things ... all at once...


it will remove chlorine and chloramine, bind ammonia, nitrite, and nitrate,        stimulate slime coat production, and buffer the pH to 7.0.


Perhaps the real answers lies here....


To lower pH below 7.0 use Neutral Regulator™ with Acid        Regulator™ (or Discus Buffer™).       
To raise pH above 7.0 use with Alkaline        Regulator™.


How does the following compare to what people are using?

The restrictions on purchase might be problematic though

US$85 for 500g / ~1lb of 'pure' Pot. Bicarb.

"This item is considered a hazardous material. These item(s) cannot be shipped to residential addresses or sold to private individuals."


For a pound of Potassium Bicarb I would expect to pay under $20 depending on how many I get and where I get it from.

Instead of looking for lab grade chemicals look for brew and wine making supplies online.  I believe it's about as hazardous as baking soda.  (which by the way could also be used to buffer pH in a real pinch but it adds sodium to the water which the plants won't like so much so isn't recommended.)

Thanks for that TC.I was wondering if what others were sourcing was as pure - bang for the buck type thing. I'll probably end up using KOH as I have easy access to thousands of gallons :) Key will be to add it VERY slowly.

I have just ordered this...It sells on amazon as well (for about double the cost of ordering 'direct')...

I bought that from Amazon and it worked fine. Be careful not to use too much. I think I used a little too much and the pH went up to 7.6. 

Thanks Michael. I'll be sure to dose carefully :)

Gen Hydro's pH Up formula differs from the powder to the liquid form, and has also changed over time. 

Before you add sources of potassium, be sure that is what you need .

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?

Potassium is a macro nutrient, so plants actually need quite  bit of it.  Deficiencies look a lot like iron deficiency (yellowing leaves with green veining, or chlorosis) but it also seems like the plant is getting older, woodier, and more bug and disease prone faster than it should.  Adding a pH Up that is based on potassium will usually increase the overall health of your is pretty hard to overdose potassium.

I have since sourced some calcium hydroxide and potassium hydroxide (builders lime and lye, both from my local hardware store) and picked up a little pH meter. I've been doing daily doses of both to slowly bring my pH back to proper levels. My pH is now perfectly under control and my fish and plants are way happier (they told me so) and healthier. I would say that I am now leery of the hydroponic products because they really don't seem very eager to properly label their ingredients and it is way more expensive. And as for my original post, the carbonates are pretty slow and rather unpredictable so I've given up on those too. 

Reply to Discussion


© 2024   Created by Sylvia Bernstein.   Powered by

Badges  |  Report an Issue  |  Terms of Service