Bacteria Issue

blkhawk10 · Aug 17, 2026

So I've had a bacteria problem for as long as I can remember. It's clear and clogs up my filter socks. I've tried everything from water changes, to changing the socks everyday to cleaning out as much as I can to adding nutrients to have measurable nitrates. I'm at my wits end and have no idea how to get rid of it. No algae grows on my glass and I have to clean the bacteria off everyday. There have been random times where algae grows and the bacteria is gone for a couple days only to come back. I don't do anything different when this happens so It's a mystery to me. I don't light candles in the house or spray any chemicals in the general vicinity. Any ideas of what is causing it and how to get rid of it would be much appreciated.

Chocka · Aug 17, 2026

blkhawk10 said:
So I've had a bacteria problem for as long as I can remember. It's clear and clogs up my filter socks. I've tried everything from water changes, to changing the socks everyday to cleaning out as much as I can to adding nutrients to have measurable nitrates. I'm at my wits end and have no idea how to get rid of it. No algae grows on my glass and I have to clean the bacteria off everyday. There have been random times where algae grows and the bacteria is gone for a couple days only to come back. I don't do anything different when this happens so It's a mystery to me. I don't light candles in the house or spray any chemicals in the general vicinity. Any ideas of what is causing it and how to get rid of it would be much appreciated.

What does that look like? I didn't know you can see that with the naked eye interested to see that.

blkhawk10 · Aug 17, 2026

It's like clear goo. some of it has a brownish tinge to it. If left alone it sits on the top of the water like in my sump and I can scoop it out with a net.

EnterName · Tuesday at 3:28 PM

If you have access to a microscope (maybe 200x or better 400x magnification) this would help to identify what you are dealing with. Most bacteria are too small to really see anything (Cyanobacteria are often an exception), but other organisms that are mat forming would be visible (such as Dinoflagellates, Chrysophytes, Diatoms, Euglenids, etc.).

It would also help a lot to have normal photos under white light of the substance you are dealing with. Can you tell us your nutrient levels (Nitrate and Phosphate) as well as alkalinity?
It would also be interesting to know what you are dosing (for example 2-part/Balling/All for Reef/Trace element solutions/etc.)

blkhawk10 · Saturday at 5:58 PM

I’ll try to get some pics under the microscope but when I tried before I couldn’t see anything. My nitrates were at 0 so I started dosing and that made the problem worse so I stopped. My phosphates are usually between .02 and .03. Alkalinity is around 9. I don’t dose anything else. After reading some posts and articles I’m thinking I have an excess of nutrients that the bacteria is feeding off of.

blkhawk10 · 2026-08-23T16:10:09-0400

Best photos I could get. Any ideas? They look like some type of worm.

EnterName · 2026-08-23T17:14:02-0400

blkhawk10 said:
Best photos I could get. Any ideas? They look like some type of worm.

What's the magnification 10x objective? 20x objective?

Did these filaments or "worms" slowly drift in one direction or were bending slowly? If yes, it's possible that they are cyanobacteria. You can see what I mean on page 3 (post #52) in my microscopy thread. Cyanobacteria filaments either rotate or just seemingly glide in a direction and sometimes bend a little bit to the side.

blkhawk10 · 2026-08-23T17:27:45-0400

It's 1200x and they weren't moving at all. I didn't see anything moving in the sample that I had.

EnterName · 2026-08-23T17:39:05-0400

blkhawk10 said:
It's 1200x and they weren't moving at all. I didn't see anything moving in the sample that I had.

How do you get to 1200x? A 60x objective and a 20x eye piece?

Most bacteria should be small rods or short spirals or just some dots even. Long filaments like in your image should point towards cyanos (there are some quite thin species so that would explain why you can't resolve more than that). I'm unaware of any actual worms like nematodes that would make it to such a small size. I assume either the magnification is different from what you assume, or it has to be some bacteria (like cyanos) that connect to form filaments.

Considering the quite low and not really dense amount of the presumed "cyanos" in those images and that you describe a clear biofilm not a red/purple one, I could imagine that these cyanos are just secondary to your issue. They commonly attach to stuff and having them here or there is not an issue and in fact, very normal.

Do you have a non-microscope image of the biofilm that is clogging up your filter socks? or on your glass?
I mean overall it's pretty normal to grow some film on the glass and filter socks (depending on micron-rating) will also clog up every two - four days or so. That's why many people switch to filter cups with some filter floss or bio-pellets.

blkhawk10 · 2026-08-23T17:53:41-0400

No idea lol. I have a cheap microscope and that's what it says the magnification is.

Depending on where I get the slime from it can have a brownish tinge to it. This seems to be the only thing growing on the glass on a daily basis recently. Like I said in my first post it will randomly go away and I'll get algae growing on the glass again and then it will come back. I've had multiple stints where I didn't have to change a filter sock for a week and the sock was just dirty and not clogged with this. I've been changing them out every other day to try and stay ahead of it. The slime seems to form the bigger globs on the surface of the water, mainly in my sump.

EnterName · 2026-08-23T18:54:09-0400

I remember two occurrences with something similar:

1. In my previous algae refugium, where the water surface was very stagnant when I got lazy and didn't harvest the macroalgae until it filled the entire chamber.
It was mostly translucent, but when scooped up from the surface and "folded" together, it appeared white.

2. A real nasty goo that formed when I was experimenting with carbon dosing in a fairly young tank. This stuff managed to clog the tube to my UV sterilizer and also had a slightly brown coloration.

Based on that, I would suggest increasing surface movement or overall water flow, avoiding anything that adds organic carbon (no vinegar/ethanol/sugar, no nitrate removers, no bacteria products or boosters, no unnecessary overfeeding, no calcium acetate or calcium formate-based products like all for reef), and patience if the tank is still young.

I'm not sure if that does the job, but I doubt it makes sense to throw an antibiotic at it especially without knowing what exactly we are dealing with and if an antibiotic would be able to target those unwanted bacteria without harming essential bacteria.