No worries.
It makes the ph of the rodi water rise.
Oyster shell may leech a little po4, but that’s where a good soak in vinegar then sw with some po4 minus comes in. I don’t do this, as I don’t mind a little po4. Typically the rock I have made increases po4 from 0.03 to .08 or so.
Most of the rock I have made takes about 3-4 weeks to cure using the lower ph grout. I always make a few fat blobs of rock thicker then the rest, as in use them as rubble for frags. At about 3 weeks, I bust one up and check it. If it isn’t cured, throw it back in and do another one a week later.
My oldest rock 30+ years old lol. My 180 is mostly diy rock that is 3-4 years old and it is doing great. When I rescaped about 4 months ago, I busted one up some to build an arch and it was full of tiny pods, brittle stars and sponges. It was also fully cured.
As for cost, it comes out to .40 cents a pound or so. The biggest thing is the wait, but to me it’s worth it, as I make shapes I want.
Here is a fts of the 180. There is 6” behind the rock for fish to swim and the only way I was able to to do this easily is with diy rock. Made edges of rock flat so the could be glued/epoxy together.
Tank before the rescape and about a month after combining a 45 and 90 into this tank. Basically a rock wall with 1/2 diy and half KP.
Sept 2020
Tank after the rescape. Has 3 arches and is still about 1/2 and half, I think. Once it’s in there a few months with real live rock, it’s hard to tell lol. Crappy pic as t5s and mh are both on and my phone hates blue+ bulbs lol.
Nov. 2020