I've been battling BBA for 1 year already and I noticed that mine were always not hairy, but instead, hard black circular lumps with "thorns". They are easily scrapped off from the driftwood too. How queer
I have noticed that black smeary algae will change to the beard form when conditions are right. Maybe your thorns are dormant and waiting to bloom? I wonder if scraping that off would be a good idea - if you can collect the scrapings? I did that when I switched tanks and so far the wood has been quite clean.
Yes, it developed on beige painted PVC. I didn't scrub it off until it grew into little bushes. After dosing with Excel the remainder came off pretty well with a Mr. Clean sponge. I had black plaques of algae on unhappy ground cover plants years ago that grew into bushes too.
Excel will do nothing to it as long as you don't overdose it. Spot treating needs any water circulation to be turned off.
I used spot treating and worked quite well. Turn off filtration. Use a syringe and squirt Excel locally. Wait like that for 5 minutes then start the filter. Once should be enough, you will see the results in a couple of days if it's BBA and not some extraterrestrial creature
I tried the excel route but it didn't do a thing :I It's only on the driftwood though, maybe it's the source of the problem, like rotting?
In this compact lumpy form, all an Excel or H2O2 spot treatment reaches and destroys is the outer layer. Repeated treatments will slowly shrink it. On driftwood, even if you're persistent enough to get all the visible spots this way, it will typically reappear in short order. I believe it burrows into the wood, so no surface treatment can fully remove it.
Only methods like boiling, followed by a scrub to remove the unsightly spots, provide a 100% kill. And if you maintain decent tank conditions, it can be months or years before the algae can reestablish itself on that piece of wood.
Mr Clean sponge is aquarium safe. I have been using one to clean algae from the acrylic tank for a couple years now. It is a micro abrasive material with no solvents or detergents in the basic original sponge. I was hesitant to use it as it will take off paint if you really go after something but all was well.
I didn't come up with the idea on my own, people have been using the original Mr. Clean sponges for years with no problems at all. The problems are all concerns so people don't want to use them, haven't ever read any actual account of something happening.
My wood doesn't have any BBA spikes on it now and I think if they develop I will scrape them off. Might knock the stuff back if I miss a water change or two.