I have a 33 gallon aquarium, that the water is remaining cloudy and has a bit of a smell to it even after doing a water change, cleaning the sand and changing the filter. any help would be appritiated.

It sounds like a bacterial outbreak maybe?

What is your water parameter? readings on ammonia, Nitrite and Nitrate?

I had this happen to me long time ago. I did a big water change and forgot dechlorinator or underdose of dechlorinator. The cloudiness comes from dead nitrifying bacteria. Too much water change can kill and nuke your biological bacteria.

What kind of sand do you have? I had a tank with some of the Carib Sea fine sands in it. I could not get the tank to clear up after waterchanges or hanging a pleated cartridge filter on it for days. ( The only filter I had on the tank was a Hydor sponge filter) I took out the sand and the tank cleared up in a few days.

The smell could be comming from pockets of anerobic bacteria in your sand/gravel bed. As waste decays, anerobic bacteria release hydrogen sulfide into the water column. Thus the "rotten egg" smell. The cloudiness is a bacterial bloom. As stated earlier, could be caused from water changing.

how did you clean the sand?I dont really"clean" mine.I use a fork or fingers to turn the sand,releasing any gasses built up.the nitrifying bact. in sand seems to do a better job than gravel at eating :poop:thats why I dont vaccum the sand but do gravel.please tell me if I'm wrong.

how did you clean the filter.. you might of killed off your nitrosonomas and nitrobacter bacteria, and know having an ammonia spike. what are your parameters reading out at? any dead spots in your tank where food can get cought and turn to waste with out being seen, or any fish that could of heed and then died and turned in to ammonia?

all i did was change out the cartridge in the marineland penguin 200 filter. it has black carrab sea sand and bunch of polyresin fake rock from petsmart as decor, when i clean the subsrate i remove all decor and use the end of the python vacum tube to swirl above the sand, trying not to bring up an sand while removing the poop and uneaten food. Using a quick test 5 in 1 strip from topfin my nitrates are at almost o, the general hardness is around 180, i put in aquarium salt with each water change, the pH is reading the same as it was before the water change. i will try to put up some pics of the tank today got to love finals time at a univeristy lol. there are 3 mbuna cichlids, a rubber lipped pleco, a catfish and 2 baby peackock cichlids in this tank.

I have used a UV sterilizer on cloudy tanks before and thats helped mine some times.

this is gonna sound kinda funny, but If your trying to get very fine particles out of the water, you need to temporarily use a finer media. such as rubber band a coffee filter over your pump intake change that out a few times and it will make a difference...

obviously this isn't solving the problem, but it will combat the symptoms