I would venture that anyone who has an acrylic reef
tank, especially a large deep one, has problems keeping algae, particularly
coralline algae, off the viewing pane or panes. Coralline algae grows on
glass also, perhaps not as readily, but it is relatively easy to scrape off
with a variety of sharp metal blades. And, there are some manufacturers
that provide attachments to cleaning magnets so that the aquarist doesn’t
have to put his or her hands into the tank. A particularly
effective one is manufactured by Ocean Motions.

However, when it comes to an acrylic tank, no matter how careful one is
with a metal blade it will scratch the tank. Currently, I have been
experimenting with using plastic blades in one of these magnetic devices –
so far, with only moderate success. If you are interested in working with
one of these plastic blades, you will find a number of manufactures that
make them, and of different hardnesses. Pictured are some of the blades I
have been experimenting with, along with an aluminum paint scrapper that
holds them. So far this works, but requires that you put your hand and arm
into the tank. The plastic scrappers made by Kent work also, but in my
opinion not as well. Paul, at Ocean Motions, is working on a new magnetic
one for acrylic, but it is not available yet.

No matter how careful you are it is hard not to scratch acrylic. So,
when I was sent a kit for removing scratches from acrylic, even underwater,
I agreed to review it. I will do so when I can find some time. If someone
cannot wait the kit is manufactured by Everclear, Transparency
Refurbishing. www.etr-inc.com, phone number
512-301-7562. They provide a variety of products developed for acrylic
aquariums, and will even send a team to your home or business to remove
scratches from inside or outside your aquarium.