Using Crushed Coral -- Advice Needed...

[Aaron]

You could also use Onyx Sand or Grey Coast Calcite (same thing). Both of those will buffer the pH and raise KH and GH.

I'm using the crushed coral in my filter for my hardwater Crypts and I agree with Jeff about it dissolving slowly.

[RTRJR]

I'm w/Christy - aragonite is sooo much more soluble than generic crushed coral that it is by far the better choice, and should be in a mesh bag in good water flow, so a filter is the best place. If you happen to have any Eheim 2211s hanging around, it is ideal - it is what I used on the 55 at the office. I ran two bags, alternating every 2-3 weeks with rinsing/drying/re-rinsing the idle bag to help clear biofilms (which may hep dissolve the stuff or may show it down - I cannot predict which). It will push GH and KH both up, but nort drastically. The shrimp use both anyway.

And no, you may not have mine. They are still available in Europe, but not here, and the power is wrong. for us. Any small empty canister should do the job. A prefilter will protect the aragonite from silting. .

[maddog10]

Hurry up and try some out before they get here! That is probably the best way to see how much it raises it, it will also act as a buffer (I think) to keep it from fluctuating wildly. How far your pH will swing after water changes depends on the difference between straight tap water and tank water with crushed coral (this will vary from town to town )

Doesn't the CO2 lower the pH?

[RTRJR]

The pH does not matter to the fish, the TDS does.