Here is the UV Sterilizer that i use for two of my biggest tanks ( 37 gallon, 29 gallon) and it works perfectly and i have never had an algae bloom since i started using them. I personally don't think that there is anything wrong with this UV Sterilizer, it is a little bulky but if you get some tall plants to cover it it's fine. This UV Sterilizer is good because it has some good flow and is just over all a good UV Sterilizer. The name of it is "COODIA Internal Green Water Killer Filter Aquarium Tank U-V Pump"