...on the inside of your aquarium, I've found a lovely way to keep the thing loking clear and free of algae that snails and tangs seem to not be able to get at.
See, our aquarium was purchased secondhand, and the inside of the glass has a lot of really fine scratches that you really can't see UNLESS algae grows in them.
In fact, it wasn't until algae DID start growing in them that we even noticed that it had scratches on the inside. It's like a fine network of scratchies in there.
...and the algae came in force once we upgraded our lighting.
It's under control now, and was gone from everywhere BUT the scratches.
The snails, tangs and urchin took care of the excess, but they either couldn't get at the stuff in the scratches or they were lazy.
We have algae scrapers (both the kind on a stick and the magnetic kind), including the type with razor blades, but none of them could get into the scratches as they were really designed for aquariums that were scratch free.
I found that the 'scrub pads' sold to clean the grates on bird cages work VERY well at removing algae from the scratches in the glass, AND they don't cause new scratches.
They're made of plastic and feel like a slightly softer brillo pad; their big selling point for bird and rodent cages is that they won't scrape off the paint or powder coating.
They work very, very well for scratched aquariums as well.
I'm not sure I'd trust them on acrylic, but for glass, they work wonders for keeping the inside clean.
Heh, and I'll be picking up a second one today so I don't have to go nuts cleaning the one we have off between cage and aquarium cleanings.