Gave up trying to clean my old 500g back pane. Too tough to reach and somewhat dangerous with inhabitants getting that far into the water. Eurobracing made it quite a challenge
I saw those too, I don't want to scrape it as it may scratch the acrylic (to make matter worst, I have black back and black bottom)...and it'll take me forever trying to clean 10x3 of area with those cute little scraper LOL
A squigie I think it's spelled attached to a screw on plastic rod or go to the car cleaning section and get one of those things on a rod that have soft little appendages hanging from them those work well
Create your own tool....necessity drives creativity! I used a plastic broom handle which I screwed into 3 sheets of styrofoam(at an angle) that I had cut to the size I wanted then attached a piece of a 50 micron fabric that I had also cut to the size of the styrofoam with enough to wrap around and attach it on the backside of the styrofoam. My tank is 4 ft wide and 3 ft tall, this works wonderfully for me.