Cloudy Tank

Question
I have had my saltwater tank established for the better part of 3 years (135 gallon). I have  fluvual 404 and 304 filters on separate sides of the tank with a 100 gallon (approximate filtration) protein skimmer hanging on the tank. I have three powerheads with filters in the tank as well. I have over 100lbs of live rock and about the same weight in a 1.5" sand bed. I have a Yellow Tang (6"), Volitan Lionfish(8-9"), Marble-Banded Cat Shark(22"), Snowflake Eel(10"), Niger Trigger (5"), and a few ~2" damsels.

Now recently (past week) the tank has become cloudy. I did a water change and cleaned all the filters when I noticed this and three days later it is still rather cloudy.

My Nitrites are a little high at 80ppm, could that be the issue? and what would be causing that?

Thanks!

Answer
Hey Ben,
It could be a few things. NItrites getting high indicate you could have had an amonia spike that you missed(they can come and go quickly). This could be from detritus, organic waste(uneaten food, something decaying in the system, etc.). Nitrates should begin to rise as nitrites fall. Nitrites can cause a slightly cloudy appearance, but it usually comes from a bacterial bloom that coincides. Larger systems sometimes experience bacterial blooms(theyre the good bacteria 99% of the time) when you have a little excess food, detritus, organic matter in the system. It should pass in a week or 2. It is the reproduction of the biological filter and is generally a good thing(other than appearance). But it does indicate possible over feeding or that someone from the community is missing in action(look for your crabs or someone that you rarely see to be missing in there decaying). Water changes will aleviate the stress of the nitrites, and at 80ppm in a 135 gallon you need to get them down. When you do your water changes, clean the filters 2 or 3 days ahead of time. This allows for the least disruption of the biological filter. If you do both in the same day you are essentially sucking out the bacterial colonies you want in the system and they have to repopulate the system. Then you will see another bacterial bloom. Like I said though, the bloom will pass and is needed for the system. I would just do the water changes and not clean the filtration for a week or 2, and suck as little as possible from the substrate(only detritus and waste thats visible) for now and you should be shaped up in a week or 2. You can do 25% of the water every 2 or 3 days. Gotta get those nitrites down. The stress from frequent water changes is better than the nitrites for your pets. Let me know if you have any more questions, Ill be glad to help!