Horrible Stinky Tank

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bubbasmomm

Aquarium Advice Newbie
Joined
Aug 23, 2013
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3
I'm new to this community, and I'm in desperate need of advice. My husband & I have had freshwater aquariums for 12 years, at one time we had 5 aquariums set up, but are now down to one 75 gallon tank. The problem is that it stinks horribly! Our whole house stinks badly, similar to cat urine. We have cats, but have black lighted the whole house and are positive now that the smell is coming from the tank. When we lift the lid, the smell is overpowering.

We do a 30 to 50 percent water change every other week, and we stir and syphon the gravel at each water change. We have an under-gravel filter and a fluval canister (made for a 100 gallon tank) on this tank. The ammonia levels & nitrate levels are very low, the levels hardly register on the tests. When we do the water changes, my husband changes the fluval charcoal & ammonia remover filtration that's inside. The water is crystal clear, the fish are very healthy, and we have no issue with algae .... And yet, the tank stinks so bad!

Do you think the problem could be the under-gravel filter? I'm wondering if there may be sludge under it that's causing the smell. We're considering taking it out.

The fish we have in it are: 3 large Angel Fish, 1 Gourami, 3 black Mollies, 4 Corys, 4 Australian Rainbows, and 4 Clown Loaches (they are small and young). They are fed flakes and small amount of slow-sinking shrimp pellets once a day.

Can anyone give us any advice to help us save our tank? We are so frustrated that we almost ready to take it down & sell it, but I hate to do that because I'll really miss it ... and yet, if we can't get rid of the smell, I'm going to agree to get rid of it.

Any advice would be appreciated. Thanks!
 
The UGF could be part of the problem, I would do a thorough cleaning of everything and do a real good search for anything decaying. Also, I don't suggest using ammonia remover, all it does is remove food from the beneficial bacteria which if you have a good colony of BB your ammonia and nitrites should be a solid and steady 0, again eliminating the need for any ammonia removers. I've never had a tank smell completely horrible, sometimes after a water change I can smell the water conditioner(a sulphur smell) but usually it has an oddly pleasing earthy smell to it
 
Do a 25% a week. Or even better, every 5 days, it might tske enough before the water gets better, this happened to my tank, but not that bad. Also, look for biozorb in your lfs. That might help with the odor, but im not positive.
 
Ya I'm not too familiar using under gravel filters but is there a way you can clean the sludge from under it? Stick the hose from your gravel vac down one of the tubes possibly? That's the only thing I can see it being.
 
You could also just remove the UGF just to be sure, with a canister rated for a larger tank along with weekly good gravel vacuums I don't see it being necessary. With the advancements in aquarium filtration technology UG filter effectiveness is debatable, its a matter of preference though I guess. HOB filters are easier to clean, easier to replace mechanical filtration media and are often more quiet all while doing a better job. In my 75 gallon I started with a HOB, then switched to a fluval 406 and by itself has kept the tank perfectly clean, though for no reason other than I wanted it I switched it out for a fx6 recently
 
break the tank down completely and wash the substrate and under gravel filter. i know i had a tank for 2 years and when i broke it down to replace the substrate it reeked real bad.
 
Thanks! We have taken out all the plants and syphoned the gravel substrate really well and then put the plants back in. Our UGF is reverse flow, but I suspect that debris can still be in it and making it smell. So I guess we'll probably remove it, then do a big water change because I'm sure that removing it will make the water pretty nasty. Hopefully the fish won't mind.

The tank has become more stinky since we started to use Prime. To me, Prime smells like the sewer. So we may try something else to see if that makes a difference too.
 
Thanks! We have taken out all the plants and syphoned the gravel substrate really well and then put the plants back in. Our UGF is reverse flow, but I suspect that debris can still be in it and making it smell. So I guess we'll probably remove it, then do a big water change because I'm sure that removing it will make the water pretty nasty. Hopefully the fish won't mind.

The tank has become more stinky since we started to use Prime. To me, Prime smells like the sewer. So we may try something else to see if that makes a difference too.

Are you making sure not to over dose the prime? On my first tank when I didn't know about cycling I was going through a fully stocked fish in cycle on a 29g and using prime at a higher dose with daily water changes and my tank did smell awful(the smell stayed in the gravel too), but now with the 75 I use 2 capfuls and even right after a WC the smell is very faint if at all.
 
Under gravel filters do trap a lot of debris, far more than I would want left in one of my tanks. You clean the sludge underneath just as mentioned, by sticking a hose down one of the upright tubes. Big enough to suck good and flexible enough to bend under a bit without kinking. Up your water changes to 50% a week that will make a difference and stop using ammo remover. I would just pull the UGF out if if were me and get a hang on back to work with the canister. Aqauclear 110 is helpful on a tank that size.
 
Are you making sure not to over dose the prime? On my first tank when I didn't know about cycling I was going through a fully stocked fish in cycle on a 29g and using prime at a higher dose with daily water changes and my tank did smell awful(the smell stayed in the gravel too), but now with the 75 I use 2 capfuls and even right after a WC the smell is very faint if at all.

I agree wit this. I do 2 50% changes a week on my 75 and also dose prime with 2 cap full. No smell.
 
Do you use carbon in your filter? If not, try that. Carbon does very well at helping remove odors. I also agree that the UGF is likely part of the smell. Finally, do you have any live plants in the tanks (I'm assuming not since you have a UGF)? Plants do a great job at consuming a lot of the organic material that can cause smells. Even adding some Marimo moss balls might help, and won't require special lighting.

Any of those three things should help reduce the smell :)
 
Update On Our Stinkt Tank

THANK YOU to all who commented on my original post. Last weekend my husband & I removed the undergravel filters, and as suspected, underneath them was a LOT of dirty crap. So then we removed 80% of the water and tried to clean the gravel as best we could .... then filled the tank with water, and once again removed 80 % of the water and cleaned the gravel. Then we filled the tank with water & put the plants back in. The tank no longer smells bad ... just a mild earthy smell when I put my nose near the water. I was afraid we'd lose some fish from the large water changes, but so far none have died. :D

Since this has saved our aquarium from being taken down & sold, we have invested in a python to make water changes easier. We have carried buckets for many years, but have decided to try the python. Any advice or tips on how to use it will be appreciated! :)
 
pythons are awesome and really easy to use. there's not much to it, except you have to dose the water conditioner to the whole tank volume instead of just the bucket volume. use a thermometer so you can get the tap water the same temperature as the tank water
 
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