If it is a turbo twist you can mount it on the top of the tank. I have mine this way, instead of in line. The reasoning is that you can always remove it easier if you find it doesn't do what you were hoping it to do . I run mine four days on, 3 days off. (The light is turned off, but the water is still circulating.) This gives the tank that little bit of algae that the corals, and my fish want, without having to be a slave to the tank glass every single day. I can definately see the difference in the tank when the uv is turned off. Be sure to get the appropriate size pump for the application that you want to use it for. In order for it to kill parasites it needs a slow pump. Even with a uv you can still get ick etc., so don't skip the quarantine tank. I use it mainly to cut down on the algae, I run my lights a long time daily and this helps tremendously.