Review on Purify and Cleanse your Aquarium with Pen Plax FBT Twin Filter Spring Aquarium Brush! by Buffy Nystrom

When it arrived the bristles were perfectly flat on both sides. It's been a few weeks and they're still not fully fluffed up, so you'll have to swirl them around in the tube to get them completely clear. The metal holding the bristles is not flexible. So if you are cleaning pipes with sharp corners, it will be difficult for the brush to get through those areas. So I had to pull the brush out again and bend the end but since the bristles are flatter on both sides you have to twist them to clean the other sides but you can't twist it over the corner while it's bent like that, as you have it Pull it out again and fold it the other way so that the corners and edges are completely clean. I've considered cutting the ends of the bristles shorter to avoid bending them, but I think all bristles can fall out depending on how it's made, so I'll try to keep the brush in a small tube until I use it Let's see if I can get it to fluff it up all the way so it's easier to use. Otherwise I have to downgrade to 2 stars.