stale fish tank odor

[sml41]

My son is at work right now but asked me to post about his saltwater tank; set up for about 8 months now; 180 gallons, 50 gallon sump ; closed tank; has 17 fish ranging from clowns, tangs, damsels; snails, live rock, sand; he tried a 40 gallon water change last week; tank still giving off an odor that is filling the basement finished room area ; a local store told him to siphon the sand or sell the fish back to them and go with a brackish tank was their advice ; before he tries siphoning sand , is this the route that he should go ; advice from anyone ; thanks !!!!!!!!

[sassafrass]

No ! please explain more about his tank, flow ,skimmer ,when you say closed do you mean it has a closed top on it ? if so that may be your problem. When looking down at the waters surface is there strong surface agitation? Afeer tank should smeel like the ocean fresh and clean .Also is the skimmer cup cleaned regularly?Above all don't take advice from anyone who stands to make money off of you . This problem can be fixed !
Lee

[sassafrass]

Sorry about the misspelled words
Lee

[RAY HUNTER]

In my experience, if your water is emitting a foul oder, your water is dirty. It is fouling. Perhaps the protien skimmer is not working properly. what are the water perameters? what about water movment? is there enough? for a FOWLR there should about 10xs the total water volume, or more! hope this helps. good luck!

[sml41]

The tank is enclosed; he wasn't making water changes b/c he was adding in large volume of water due to evaporation; he has the sump pump with the bag filtration ; he has 2-400 gallon per hour powerheads ;comes back in at 1800 gallons per hour; skimmer cup does need to be cleaned

[sassafrass]

The skimmer cup has air flowing out of it ,thats how a skimmer works .I would start with cleaning that it will help the skimmer to perform better as well.As RAYHUNTER said dirty water also, water changes are vital because only pure water evaporates testing for nitrates is a good place to start so as you do water changes the nitrate levels will go down.
Lee

[RyanMKintz]

Also in water change you get those lovely trace elements

[Flipper62]

evaporation does not get rid of the fish pee & poop, as well as the old food that didn't get eaten & settled to the bottom. This all adds to the phosphate & nitrate levels

On a 180 gallon, he should do a 20% water change every 2 weeks.

Seems he should have done a lot more research before setting this tank up.