Backyard Aquaponics
A place to discuss aquaponics

I couldn't find any info on actual whole coral skeletons but I did find alot on crushed coral and shell grit. Can anyone tell me if they've used chunks of coral (dead of course) for pH buffering? I would think it's no different than crushed coral right? I just have alot lying around my house.
I only ask because I was reading up on using diy plaster of paris tablets and figured out that it's essentially the same stuff as a coral skeleton. Anyway, any assistance would be much appreciated.

Basically Calcium Carbonate... like shells... so yep, should buffer just fine... probably not as quickly as crushed shells/shell grit though... matter of surface area I suppose... and anything else that forms the outer casing...

Probably also be a good bacterial bed...

I thought there was info on here previously that coral's ability to buffer will stop after some time due to the available calcium being used up or something like that?

It would be worth testing out some of that coral to see what pH it actually buffers to. And yes I believe there were some reports that certain types of shells and coral might reach a point where calcium is used up so it might appear that there is coral left but it might no longer be buffering at some point.

I'm sure it would be worth something as media even if it does reach a point of non buffering.

Think you will find it is the carbonate side of the 'rock' which buffers. Depending on the reactions and hardness calcium can become an insoluble form and precipitate out.

I use crushed coral or coral rubble in 900L aquarium to buffer PH. I placed about a 1kg of it in a mesh bag in a sump filter. Works well so far, have had it in there since Xmas.

Given a long enough soak, the pH should raise to 8.5 or so, for limestone or coral. And the water might get cloudy in time.