I just installed an aeration system and it's still in the early startup phase. However in cleaning up my floating fountain pump to put it back in service I found it was covered in a heavy brown algae and needed something to scrape it off. It had also grown inside the pump screen and was so dense it had a meaty texture.

For FA I'd usually use copper sulfate sprayed on it and the water surrounding the mats. Not sure how to deal with this brown stuff. I also pulled out a 2nd pump that had only been in the water about 3 weeks and it's covered as well. Both of these were down about the 2 foot depth so not sure if it's deeper than that or not. However the waterfall I restarted also has brown stuff growing on the new liner and that water comes from 5 feet below the surface so I suspect it's at all depths.

I didn't get any pictures as I was too involved in getting things cleaned up and back into the pond but can grab some tomorrow.

Is this something the aeration will take care of once the system is running full out or does it need to be attacked some other way?

Doing some reading today and it seems like this may be related to diatoms.

I've also got some dark streaks/bands of water in the pond so the two may be coupled as I only saw the dark bands of water a couple of weeks ago - around the same time I added the pump to move more water before I decided to do the aeration system.

Here's one of the dark streaks which is more visible after adding some pond dye.



I'll get some picture of the stuff attached to the pump tonight.

Here's what the stuff looks like on the pump that was in the water for about 3 weeks or so. This is the first time I've seen this in the 10 years I've been dealing with the pond.

Wipe some of it away, leave some, Extra water changes, gravel vacs will help but will go away on its own. Needs to run its course. Pond needs to mature. I know it's ugly. Be patient.
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Check out the term detritus. If its alive I would guess its not simply diatoms. A good close up pic may help.

Following on this thread, just recently I found some of this as well and thought of it as brown algae.