dirty sandbed

So currently tank is about 2 months old I do run my lights a little too long so I did cut it down and just started a 2-3 day black out period but I do have 6-8 blue legged hermit crabs , nassarious snail, & a large turbo snail ? Will the 3 days no lights help get it back to near white?

I have a question for the Reefing community, my boyfriend and I have had a reef tank a little over a year almost two now and within the past 6-7 months have added a lot of NPS, mainly gorgonian/sea fans to our 125 gallon reef tank. Ever since we've been trying to add a dependable clean up crew...

Hello can anyone suggest what can be done for dirty sand bed I have setup bio cube for 3 weeks now and not sure where the dirt is coming from, I have attached picture with and without light want to know if its due to new tank or I need to do anything