Brevin

I'd like to start by saying this a great forum and the information within has helped me immensely. I couldn't find an answer to my current problem, so I have to stop lurking.

I've been have weird brown water, that seems to be free floating diatom algae. Now from what I know, diatom algae only occurs in new tanks, however, I've had my tank for 3 years now as an established tank. I changed the lights to PC lighting 6 months ago and added pressurized CO2 via a glass diffuser around 3~4 months ago. I had problems with BGA, which a powerhead solved, with its increased circulation and regular dosing has thread algae virtually gone.

However, I still had diatom algae, the brown gunky stuff that you can get off your leaves fairly easily. The diatom algae even covered my thread algae, which created this fluffy, nasty thread algae. What I find interesting is that alot of the diatom algae is on the upper leaves and I've heard it prefers low light. So I upped my NO3 dosing to every day. However, that got my NO3 values to 80ppm quickly and one of my cories died. I went back to my original dosing thinking that after I got my algae crew that it would be beaten down.

Sometime around 2 weeks ago, I started getting an haziness in my tank. I was worried it was green water, but my tank turned a murky brown water. Almost like tannins, except I have no wood in there. I've tried, changing the lighting schedule, both longer and shorter. I've also changed the lighting intensity, but to no avail. I've also tried frequent water changes, but within 12 hrs it is brown again. It also seems to clear up in the middle of the night, almost like plants getting used to the light cycle, clearing up when there is no light and getting brown again in anticipation of the light in the morning.

I'll post a picture tonight when I get home.

Thanks,
Felix

My tank spec are below:
20 GallonH
Not sure of my CO2 levels, but my plants pearl well, and I have no more BGA. It is hard to test as my KH is 30 degrees. We have liquid rock here in Wisconsin.
8hr lighting with 55W; 2 hr with 33W
Dose EI:
every other day
2/8tsb KNO3
1/16 Mono potassium phosphate
1/8th Potassium Chloride
and
1/16 CSM+B on the off days.
and weekly water changes.

Brevin

I forgot to mention, after I change the water, it looks better, but within 30min, lots of the leaves are covered with this brown muck. Really nasty, always the area near fast moving water.

abnormalsanon

I'm having the same problem with brown algae in my two-month-old goldfish tank. I've never had it last this long in a new tank and it's coating absolutely everything. (No brown water though.) I'll be interested to see what folks have to say...

Brevin

Well the brown water seems to have subsided. I'm knocking on wood at this point. It seemed, running the CO2 diffuser underneath my Eheim intake caused brown water. The canister filter is 6mo old, so maybe the concentrated acid caused a leak of silicon into the water? Maybe, the current levels of diatom algae are a result of the silicon tubes? Thoughts?

Brevin

Hmm, no suggestions? Do you need more information or pictures? To tell you the truth I'm not even sure it is algae. I'll tell you what, I'll bring some slides home and take a sample of it and take some pictures under the microscope.

MatPat

I have no experience with free floating diatom algae but your situation sounds an awful lot like Green Water to me. In the initial stages, green water isn't really green at all but has more of a murky cloudy look to the water.

I see you have an Eheim is there any chance that it may get vapor locked during the day when injecting CO2. I had this happen to my Eheim Ecco a coupe of times when I "heavily" injected CO2 into it. It was still very quiet but there was not output at the spray bar. After starting it back up it would make the water very cloudy. Makes me think the bacteria died in the filter due to lack of O2 since the filter was not running.

Also, how often do you clean the filter?

Brevin

In Response to MatPat:

I don't believe it is green water, I've had this murky brown stuff for a while now, and it is definitely brown not cloudy. I've never seen anything like the pea soup. I don't think it is bacteria either, as you can see the pictures below, looks like diatom algae to me. The filter gets cleaned maybe every month, I just change out the filter floss.

However, I do believe, that I agree that the injected CO2 into the inlet caused whatever is in my filter to blow into the aquarium and free float. Still can't figure out what is happening there.

So as promised, I took some pictures on our microscope of what is currently on my leaves and in the water. It is a 100x magnification if I remember right. If you look under a light microscope it is noticeably brown. This is taken with a laser, so it is a monochrome image.


This is it at 600x magnification:


It looks very similar to the macro photos of diatom algae on this website, squarish in shape.
Aquarium Algae

Any suggestions on getting rid of this stuff? I've tried raising nitrates and intensity of the light, hasn't helped. Any thoughts?

Mud Pie Mama

You sure do have a mystery on your hands. I see you mentioned adding pressurized CO2 a few months ago.

I don't know if this will pertain to your situation but, when I first started upgrading my 75g tank towards a fast growing, high light set up (second filter, second bank of lights, pressurized CO2, etc); I had a great mystery on my hands too. My water started getting murky and cloudy, and it always came back after water changes. After much head bashing, etc.... I discovered that the lower Ph levels from the carbonic acids in the CO2 was causing the limestone contaminates in my pea gravel to dissolve at a phenomenal rate. My Kh was climbing thru the roof in just days and the tank kept going cloudy. I ended up overhauling the tank and changing out all the substrate. It was agonizing (pitched out over $100.00 worth of substrate), back-breaking work, but now the tank has been running great.

I'm not saying its your substrate but maybe something is dissolving, which feeds those diatoms. I think its pretty cool that you can get a microscopic photo of these! I wish you luck getting to the bottom of this.