Surface Scum

[Allen_1971]

I know that many of us have had surface scum in our tanks, and the typical recommendation is to use a skimmer, something that eats it to physically remove it...

I was just wondering though, does anyone have any insight as to what exactly causes this?

[geoffrey]

Allen,

Walstad has a good write out in her book under Bacteria, Biofilm. You may want to finger thru those pages again. I did that couple of days ago.

[vinz]

Not too sure. It's supposedly plant protien and bacteria feeding of the protein and/or ferts/minerals/vitamins.

[Allen_1971]

Yes thats more or less what I understand... its just pretty frustrating to leave it at that. and anytime you try and understand more, people start giving solutions... sigh, probably cuz the solution is so simple, people don't bother to understand the problem...

[vinz]

Incidently, I notice less scum in my 6ft last night.

Possible causes:
1. Changed to daily fertiliser dosing instead of every other day. Dosing amounts adjusted accordingly. Started early this week.
2. Drop in temp due to cooler weather from 28 to 27 degrees celcius.
3. Raised NO3 up to 10ppm 2 days ago via KNO3. Probably resulting in better uptake of fertiliser.

Did notice better growth in APP in the last few days too.

[DEA]

scum will break down
if your fish are dying, it's usually not because of the scum
ie it's the end result, not the cause

i suggest you change your water first and clean out your filter
the scum should resolve itself