bro do not change water or change filter wool as it will affect the cycling stage and
by doing so may make the cycling stage longer
yep since there is a layer of dirt on the sand see if its red or green if its red siphon them out and use red slime remover
also add a wave maker to allow circulation there
secondly I think that since u have spend so much on stuff why not go directly to corals is not I believe one day u will stil come to the coral part
hahah I experience it before