brown sludge in filter

**aqua007** · 23rd Jul 2017, 10:51

Dear All,

Recently I got problem.
I start developing brown sludge/algae in my canister filter.
Every 1-2 months its slow down the water flow and eventually the flow is very slow.
Any advice to get rid of it?

Thanks.

**shoelevy** · 11th Aug 2017, 14:31

i notice the same brown sludge in my canister filter when i clean it once every 6 months or so. it is correlated with persistently high NO3 in my tank, and i use the high nitrates to tell me when cleaning the filter is due. I don't think however that it is algae as algae seems to grown better under light in my main tank. So in my case, i do think the sludge of debris made up of fish poop, decaying leaves and uneaten food.

Do you have a high fish bio-load or feed a lot? DO you also have high nitrate when the sludge forms?

**aqua007** · 12th Aug 2017, 11:25

Originally Posted by shoelevy

i notice the same brown sludge in my canister filter when i clean it once every 6 months or so. it is correlated with persistently high NO3 in my tank, and i use the high nitrates to tell me when cleaning the filter is due. I don't think however that it is algae as algae seems to grown better under light in my main tank. So in my case, i do think the sludge of debris made up of fish poop, decaying leaves and uneaten food.

Do you have a high fish bio-load or feed a lot? DO you also have high nitrate when the sludge forms?

Hi Shoelevy,
No, the nitrate level is not very high. Normally its around 10 or 15. I didn't check recently but couple of months back its the same.
I can say my tank is a bit overstock. I have around 30+ fishes in my 30 Gallon tank in combination of 20 Tetra, 8 Platies, 4 dwarf gold fish and couple of algae eater and cory cats. I don't see much of fish poop. I have a planted tank with lots of variety of plants, so i think the poop serve as fertilizer for plants.

My filter clogs every 2-3 months. then water flow stops and require to clean. I tried cleaning media and filter with bleach, salt water and algae remover, but no luck.

Not sure whether its algae or sludge, but looks like brown fiber algae..

I notice that my tank have high GH. Tried all methods but not getting the GH down.

**shoelevy** · 13th Aug 2017, 13:37

I have similar bioloads as you do but i think i have closer to 40 fishes

.

30 Gallon tank: 10 rummy noses, 9 neon tetra, 1 betta, 4 corydoras, 3 whitefin tetras, 3 platys, 1 SAE, 2 OTO, 1 boeseman rainbow, 2 pseudomogils and 1 danio

I feed 2 cubes of frozen food a day and i also have plants like java, lily, cryto, echinodorus, though they are slow growing and i have recently introduced dwarf duckweed to help keep nitrates low.

But i have to thank you for raising this topic because i've never thought much about the sludge. Your post prompted me to do some homework on google. It seems that most hobbyists esp. those with high bioload tanks encounter such sludge. Seems perfectly normal and people think it's either biofilm from good bacteria or suspended solids that get pulled into the filter. I highly doubt algae, which requires light to grow. So either way, it's not a bad thing. So can we agree that the sludge isn't causing direct problems for your livestock?

Also, I can go for months without a flow choke like you've encountered. But i assure you i have lots of sludge in my filter whenever high nitrates prompt me to clean it once in 6 months. But i'm running an eheim pro 3 with lots of volume and flow power. What filter are you using?