Backyard Aquaponics
A place to discuss aquaponics

What might cause PH to swing on a newly cycled system with no fish and a few seedlings growing - anywhere from 6 to 7.5 currently? How much shell grit might fix this, and should you just chuck it into the bottom of the FT or what?

Which way is it swinging Ryan... when... and is there any algael bloom?

A sudden drop in pH after a system cycles up is not uncommon, it is the bacteria using up carbon. I would add shell grit in where the water has to pass through it. If a single inlet into the grow beds, add some there.

If the pH is swinging up and down. Do an early morning test like a dawn and another late in the afternoon. If the pH is low at dawn and high late in the day, then I tend to blame algae. Is there algae in the system? Use shade to combat the algae before you go too nuts trying to stabilize the pH. Once the pH stops swinging so much, you can then figure out if it needs more buffering.

Remember that buffering only works to keep pH above a certain pH, it won't help to bring pH down.

Hi Ryan

I put my shell grit in an ice cream container and just leave it in my tank. I replaced the shell grit with egg shells recently, only because I have chooks and eggs shells are a waste product

cheers
Derek