Powerhead AND above tank filter box Questions!

[missblonde]

So I have the old school (I think they're not around anymore) Lifetech reef tank. The stock filter is a box above the tank - it runs the length of the tank and is about 8 inches wide. It has a powerhead that pulls water up into it, it flows out of a long tube and falls onto filter pads along the length of the box then out the other side and back into the tank. How do I clean this since it doesn't come off without getting water and everything everywhere? It has filter pads and bio-max noddle things (I know, educated description) in it currently.

Along those lines I also have a Fluval 305 canister on the tank and the two combined don't really create much flow in the tank. The above tank just drops water into the tank and the fluval has a little exit tube thing that pushes water out. I am considering adding a powerhead to the tank - any relatively affordable suggestions for my 36 gallon?

 

[missblonde]

Also I have a Cabbage Leather Coral and Mushrooms to consider with the flow - not sure if they dislike too much flow. Before I add more fish I want to be sure the bioload and filtration is up to par. Currently only houses a clownfish that came with the tank.

 

[OldReefGuy]

They like indirect flow, especially the shrooms. Surprised the 305 isnt flowing enough...thats a pretty good filter with good flow .... Adding a powerhead willl help.