To view the above pics, right click on them and "view image".
I reposted the important one, below: The pic of the scrubber.
Well, to save you some time and frustration, you are going to have to rebuild it. The problem with the current one is that the lights are two weak, and too far away from the screen, to do any good. Your plumbing/draining problem is a different problem, easily solved by having the drain line run straight down to your display (no ups and downs... only down).
I know you said that your previous worked wonderfully, but if it did, there would be no green in the tank. But regardless of the previous one, the current one (pic below) is not going to do any filtering for a 350 gal tank. You have plenty of room outside the house, so why not get another plastic box and do one that will work good even when your tank is stocked.
You have very little stock, so you can go with the minimum lighting: 0.5 watts/gal = 175 watts. You need 350 square inches of screen lit on both sides; either a single big screen, or two smaller ones like your current one. I would get another new box, make one 24" wide screen that is 14" tall, and use CFL floodlights attached through holes in the sides (look through the examples for ideas:
viewtopic.php?f=3&t=26
A 24" X 14 screen will need at least 4 bulbs on each side, in order to give fairly even coverage of light. It's not nearly as good at T5HO, but much better than one big bulb in the middle. So each side of the screen needs about 85 watts, so each bulb can be about 23watts or 19watts:
http://www.buylighting.com/23-Watt-R40- ... 1r4023.htm