Could it be considered a bacterial bloom? I added liquid calcium one time thinking it was calcium cloride. It was Polygluconate calcium. It did that as part of a bacterial bloom but it didn't last that long
Hard to tell without all the info on the system. The cloudiness could be a bacterial bloom. Are you breaking in those lights slowly? I have the same ones on my new tank and have been running the 20 blue and 5 full spectrum, gradually bumping them up once a week. Also keeping the photo period shorter than usual. Blues for only 6 hrs, full specs for 4. A sudden algae/diatom bloom could be light related. What are your nitrates at?
Don't do that. There is an explanation for it, you just have to sort it one thing at a time. Many factors. What are your parimeters? What are you adding for food? What's your filtration? What test kit are you using for nitrates?
Lawton, it definitely seems to be bacteria issues. I cannot tell if the brown is dinos or diatoms, but it looks to be a flow issue and possibly excess feeding and lights. What are you running your OR's at? Intensity and how many hours per day? Try cutting back the photoperiod first. Get some snails and see if they eat the brown stuff, if they do, it's probably diatoms. Run some carbon for sure, maybe do another water change, I know you said you just did one last week, but wouldn't hurt to get another one done. As others have said, you need to pinpoint the problem. To me it seems you have a flow issue, as in, not enough. You might need some more flow across the sand. Do some research on diatoms and dinoflagellates. You said you dosed chemi-clean, when did you do that?
No skimmer why i said tear down so i can redo the sump my sump only holds like 5 gallons ots small for the tank i think and could help with a large sump