The Puffer Forum

BLACK ALGAE in a Light Brackish Tank- Grrr

Aparently does no harm to the fish, but is unsightly, and spreading like mad! How to get rid, once and for all!?

Been black algae free for months, added another fish this week, and the black algae is back.

A friend suggested putting bog wood in freezer to kill it, which I have done, but am now loathe to return to tank.

All lid lights are now off. only light available is an external SAD light, which is only on for 2 hours a day, and not directed at the tank.
Tank isn't in direct sunlight

all water levels acceptable.

Ideas please folks??

I don't know where the idea came from that a tank has to be in direct sunlight to grow algae. My tanks are all close to my door (away from my window) AND my window is painted, so my room is actually pretty dark. Only my tanks get concentrated light. Yet my 10gal and one of my 5 gal consistently grow algae.
I've read somewhere that algae can also grow in too little light. Also that not having enough oxygen in the tank or having hard water (all the extra nutrients are just an invitiation) will cause algae growth. I think mine's the last one.

Black algae is known for having strong roots, so the only way to get rid of it is to kill it entirely. Freezing may have done the trick. You could also try washing in a bleach solution and then thoroughly rinsing. If you repeatedly use certain containers (buckets, iow) for washing/storing fishy stuffs, you may have to wash them too as they may have strains in them as well.

Is this the same as brown algae? The stuff that sticks to the glass, the plants, everything? I have this horribly in one of my brackish tanks. I clean it up and it comes back within days. It's nuts! I haven't found anything that helps, but have heard just cleaning it and eventually it may go away someday? I think I'm going to take my decorations out tomorrow and clean them off as best as I can. Good luck!

I believe "black algae" is cyanobacteria, not algae. Chemiclean worked for me.

Cyanobacteria is blue-green algae... only know that b/c the lake I live on has it right now due to the flooding... Not sure if that's the same also though.

It can be black or red too.