I' sure this has been covered before, but I haven't found it. I have a 55 that I would like to switch over to fish only salt. Is salt any more difficult to maintain than fresh / brackish? Is 55 large enough to be stable? I will likely drill the thing and add a sump, which will add some water volume. The sump would only be about 20 gallons so I can't imagine it will add much stability. The other question is if I need to replace my substrate. Its currently a mix of argonite and crushed coral.
