Backyard Aquaponics
A place to discuss aquaponics

I've heard that pecan shells are acidic and read that they are at pH 4.8 (not the pecan meat though). How well would this buffer a normally high alkaline system compared to driftwood/deadwood? Has anybody tried it? Is it worth trying? Should I take one for the team?

I don't know how the shells would work or if there is anything about them that would be bad for fish.

What I do know is if your media is a strong high buffer material, it doesn't work all that well to try and acidify the system. I ran a test for months with wood chips in the pee ponic system. I had one bed full of shells, one bed full of river rock, and one bed full of wood chips. Turned the water very dark with all the tannins but really didn't affect the overall pH much.

The only thing I've seen to have a mild effect on the pH of my system is when I add lots of chleated iron regularly I might see a pH closer to 7.5 for several days to a week as opposed to my normal 7.6 and above. Don't go overdosing iron though as that is not really good for fish either, you only want enough iron to keep the plants happy since too much can be toxic.

I was thinking of using crushed pecan shells as grow media. If it only dropped the system down .1 or so it would help the system a tiny bit. Now that I think about it, they might float anyhow, eh?

Hello, I haven't posted much but I listen and learn as much as possible. I started my new raft system in April with 225 six inch catfish in my 2000 gal. system. I have a problem with my pH. It keeps climbing and right now is 8.4. I keep adding distilled white vinegar, a gallon at a time and it take the pH down to abot 7.8 but then slowly climbs again after a day and a half. My readings are--nitrates-0, nitrites-0, total hardness-300, total alk-180, ammonia-0-0.5. Not sure what to think or do??? Any advice would be appreciated.

There is no gravel in the system at all? What are you using for filtration?

I have two 50 gallon vortex filters in series with a settling tank and my system pump runs continously.

Tony from West Oz had a similar problem with one of his ponds - it turned out the water he was adding had a really high PH after sitting for a few day (outgassing of CO2 or something) - might want to try bubbling a bucket of water from your tap overnight, and see what it comes out as.

I'm using collected rain water and lake water, pH of those are just above 7. and the return water to the fish tank is sprayed onto the surface for aeration and degassing.?? I do have quite a bit of algae in the system. I have installed a 70% shade cloth over the fish tank to reduce sunlight.

one method to use is to add peat moss to your system. it breaks down and can be fairly strongly acidic to the point of getting to 4-5pH. Have a look on the web and see what you find.

Thanks Nick, I do have access to Peat moss locally and will give it a try. My catfish stopped eating and I'm getting a bit worried.