By scrubbing the tank I meant that I hand pulled-off as much of the cyanobacterial gunk that was forming on the rocks, plant leaves, and grape wood as possible with my fingers and placed them in a cup which I flushed down the toilet. I didn't touch my filter media, and only took the carbon out the next day after the first maracyn dose because I realized I had rinsed the carbon filter out (in tank water) two weeks before. I know it is unwise to clean the filter out entirely, and I haven't touched the other two sections of my filter for a month or more... and have only rinsed them off in tank water, and never within 2 weeks of each other. I rarely even vacuum more than 1/2 the tanks gravel during small weekly water changes. I would like to have an air driven sponge filter in my tank, but lack the space for such additions. I try not to remove too many leaves at once, often leaving trimmings in the tank to root them and only take out completely dead leaves that don't seem to be getting attention from the snails.
I suppose the removal of all the algae could have been a problem, but I waited a good week after doing this before the water change/fish addition. I added fresh carbon back into the tank 3-4 days before the water change, and had ran it under several cups of tank water. I plan on waiting a week or two after the next batch of GBRs arrive at the AH before picking any up and will be careful to not mess with the tank much for a few days before that.