Mildew/mold on sponge filter and bio rings

[pednurkim]

I was cleaning out some clogging on my Aquaclear 110 intake tubes and noticed it smelled like mildew. There are a few bio rings that have mildew spots on them. My air driven sponge filter came from a lfs to jump start my cycle when first setting up the aquarium. It is a 125 gallon with fish added 2 weeks ago after fishless cycle. The fish all seem to be doing well. I haven't cleaned the sponge filter yet, but the air hose became unattached. When I lifted it, I smelled a mildew smell. Do I need to replace the sponge filter? Will that get rid of too much bacteria for the cycle? I want to change out that filter for a course sponge anyway, but I'm concerned it will just seed the mildew/mold to that sponge if I leave the old in with the new for bacteria transfer. I haven't noticed black on the Aquaclear media other than the few bio rings that I removed.

 

[Uberhoust]

How long have you kept the tank, are you a relatively new fish keeper? When I clean my filters, I have the same filter as you on one tank, there can be a earthy smell to the sponge portion of the filter, when you rinse it brown material will come from it. I call it earthy because it kind of smells like potting soil to me. This smell is normal and indicates that things are working right, it shouldn't smell bad, but it does have a smell.

If you have offensive smells that will indicate something is wrong. I find the smell of Cyanobacteria bad and can notice it right away now. But I have never got cyanobacteria growing in my filter.

Is the filter exposed to light, in my cases they are not, but if they were you could have cyanobacteria on your filter media, especially on the upper surface. If the black is sort of green this could be what is on the bio rings.

I rinse the sponge from my filters in some aquarium water during the water change, usually every 2 weeks. The bio rings I also briefly rinse in aquarium water. The rings do get discolored and I have never worried about it.

Rather than guess it might be good if you sent a picture and how you maintain your tank. I haven't heard of mold growing on the bio media, but then I did my own thing for years before coming across this forum.

 

[pednurkim]

I have had aquariums for a few years. I have a 10, 20 and 55 gallon aquarium in addition to the 125. My other aquariums don't have this. Just the normal brown color and smells you mentioned. The smell is like mildew you would have in a shower or something that didn't dry out completely. The sponge filter in the AC110 seems fine, although I have not removed it. I don't like to mess with the filter sponge within the 1st month of adding fish. The aquarium was cycling and maintained for about 2 months before adding the fish I have in it now. I changed my mind on stocking, so it took longer to add them.

 

[pednurkim]

This is the filter and the bio rings that were affected.

 

[Uberhoust]

Sponge filter looks normal to me. And the black stuff on the rings I wouldn't worry about either. But I will check mine when I get home for comparison. You say these items smell bad, which, we can't really ignore. Is there any other evidence of an issue other than the filter and biomedia. I had a fight with Cyanobacteria recently which I only got rid of by removing everything sterilizing it and re-making the tank, it had a unpleasant smell, but it wasn't a bathroom mold smell.

Is it possible that the rings were above the water line in the filter? I try to keep mine totally submerged.

 

[pednurkim]

Everything else seems fine. Fish are active and eating, ammonia and nitrites 0, nitrates 5. 3 of the rings were right at the water line, but the others weren't. I never would gave thought anything was wrong until the smell. The water itself doesn't smell whe the tank lid is opened.

 

[Uberhoust]

Given your history you should know if your fish are acting normal or not. I wouldn't worry too much about the staining on the rings. I really don't know where the smell could be coming. Likely it will either get worse making diagnosis easier or it will go away. Nitrates of 5 is pretty low.

 

[Archerfish]

This is the filter and the bio rings that were affected.

I have sponge filters in all of my tanks and will make this guess: Your sponge filter has reached its lifetime usefulness and is clogged with all sorts of debris. CIt is time to replace it. In the meantime, can you run a course filter (as you mentioned) along with this old filter at the same time? If so, here is what you need: A clean (new) toothbrush, bucket and a siphon hose. Use siphoned tank water to flow over the old sponge as you gently scrub the sponge clean. Then repeatedly, 'squish' the filter a multiple times in a bucket of tank water until the water is mostly clear. You should get a couple of weeks of use from the old sponge as the new course sponge gets seeded.

 

[pednurkim]

Thank you both! Do you think since I have the Aquaclear 110 also running with the spongefor it plus a sponge from my 55 cut in half in the media basket, I could just remove the old sponge filter? Would the Aquaclear sponges be enough? Nitrates are low I'm sure because I am building up the stock. Right now there are 5 rainbowfish, 4 Congo tetras and 3 corydoras. Getting 10-15 cherry barbs this weekend. I will be getting more Congos once lfs gets more in. More rainbowfish later also.

 

[Uberhoust]

FYI my bio substrate does not have any black staining nor smells bad. They do have a light biofilm that is slight tan in color. The flakes of dark colored bits are part of the substrate.

 

[pednurkim]

That is what mine look like in the other aquariums. I think I am just going to replace the sponge filter so this doesn't spread. The worst smell seems to be coming from it. Hopefully with the small number of fish I have right now, the sponge in the Aquaclear will be enough until the other seeds.