jgon_

One of my tanks has this dark green and black algae that's covering and killing my plants. I can't figure out exactly what kind it is. It's not brush algae since it is not furry or in tufts.

I've added to new plants which seem to do well for about a week. Then they stop growing and begin forming these dark black spots and areas on them. Eventually the plants stop growing and the edges of the leaves begin to turn a light brownish-green. I've read over the signs for specific nutrient deficiencies but cannot find one to match this. The algae can be scraped off the leaves with razor, so I know its something growing on the leaves and not the leaves dying themselves.

The tank is 35 gallons. 1.5-2 WPG, with all low light plants (wisteria, anubias etc). The lights are on for 8hr a day. I fertilize the tank with API Leafzone and Flourish Excel once a week when I do water changes and have Eco-complete substrate. Water parameters are fine and fish are happy.

I've read that overdosing with Excel may work, but what qualifies as 'over dosing' and for how long am I supposed to do it.

Any other suggestions, or anyone with similar experiences?

Nate McFin

I would just spot treat with excel. If you dont have a medicine syringe this is the easiest to use. Turn off the filter. Squirt the Excel onto the leaves that are affected. Let it sit for a few minutes before turning the filter back on. Removing the worst leaves is also a good idea. This type of Algae seems to grow very slowly thankfully as it has been a pain to actually get rid of! ( I haven't yet)
I would up your dosage to Seachems recommended. You should be adding excel everyday to every other day. (In smaller amounts than the water change amount!)
I would not myself even consider overdosing this stuff with fish in the tank. It is a hospital sterilizer and a poison.

jgon_

Thanks for the advice! I think I'll give the tank a big water change this week and do some serious pruning too along with the treatment.