I am trying to get my scrubber to outcompete what’s in the display but the stuff is spreading like wildfire.
@b4tn still using the L2, correct? I wish my customers would tag me when they're having issues, that's what I'm here for!


My scrubber is going for 16 hours alternating light schedule.
Based on this post:
https://www.reef2reef.com/threads/s...ics-algae-scrubber.293235/page-5#post-4363028
What intensity are the LEDs set at?
{thread above says 3 o'clock}
What duration?
{I mentioned going to 20 hours}
How much flow are you running on the scrubber?
How often do you harvest?
{I think every 2 weeks?}
How aggressively do you clean the screen?
How much are you feeding on an average daily basis?
What other filtration do you have in play?
Should I scrub as much as I can off the rocks till the scrubber catches?
You can pull algae off, but I wouldn't scrub the rocks, at least not all of them and not aggressively - you can remove the periphyton layer and kick off other things like dino outbreaks, so be careful of that.
If I try and grab it it falls apart in my fingers. I can’t pull it off the rocks. The only way to remove it is to scrub with a stiff tooth brush.
That's most likely GHA
The algae started from a massive die off when my son over fed and caused a cycle while I was gone for a month. Parameters are back to normal but all this started.
This explains it - what you could be seeing here is a short-term depositing of nutrients into the rock, and now that you've lowered the nutrient level in the water column, those nutrients are getting pulled out. The algae is opportunistic and it's got a fuel source, flow, and light...so those are the perfect conditions.
This is, IMO, a temporary situation, the scrubber will eventually beat it back out. You will want to keep in mind that as the problem abates, if you have cranked up the scrubber as part of that process, you might have to dial it back a bit.