Started FOWLR well recycled with Fish, live rock and a cleaner crew - ended up travelling overseas - had some body to maintain - the person just kept topping up with RO/DI (used it without changing filter for 1 year) - most fish & cleaner crew died - just 1 yellow tang and a few snails left - tank has algae and a lot of large critters (some star fish kind) on live rock - how do I know if there is too much biowaste in my tank - can I replace all of the water but keep the live rock and start all over - Have 1 wet dry filter, 2 protein skimmers - Please advice