Do you know if the water is RO water or RO/DI? What will you be topping the evaporated water with? Strongly discourage you from using tap water b/c of the TDS (total dissolved solids), and all those unknowns. If least get distilled water w/ no salt mixed in. What happens is when the water evaporates, the salt is left behind, raising the salinity. If you added more saltwater to make of for the evaporated water, you'd slowly raise your salinity and possibly kill your corals/inverts and maybe your fish if it got too high. You don't breed them. They just populate your tank so fast if you add some live rock. I had all base rock and got mine from macroalgae in my refugium. They got sucked up to the DT and covered so much of the glass. Nice treats for the fish too!