I have a 4x2x2 ft planted tank. 9 altums in it, beautiful! 2 problems... 1. they keep up-rooting my tenellus!! 2. the bioload is high and creates algae problem. the green slimy type on glass that causes water to smell.

I was told by friend that there is a mechanism that can remove algae effectively. Glass/plastic cylinder attached to the filter pump, gushes a series of sand like particles to remove impurities in the water. need to change particles quarterly.

Can someone elaborate and show me a lead to this item?? Thanks in advance