Hi Alex,
i used to have the same problem with the sand going brown, detrius etc. In mine i now have 3 Blue Cheek Goby's, they turn the sand over quite regularly and are also a real joy to watch !!!
Looking at the rocks still, have you got them off the sand? i.e. using something like egg crate ?
Only ask as rocks sitting directly on the sand will only help to trap more crud, thus leading to possibly high nitrates..
i used to have the same problem with the sand going brown, detrius etc. In mine i now have 3 Blue Cheek Goby's, they turn the sand over quite regularly and are also a real joy to watch !!!
Looking at the rocks still, have you got them off the sand? i.e. using something like egg crate ?
Only ask as rocks sitting directly on the sand will only help to trap more crud, thus leading to possibly high nitrates..