1. There are reports of running them in water deep enough to cover the outlet ( top of the riser tube ). I run mine in 8-9" of water.
2. Avoid any contact between the skimmer/attached piper/pump and the edges of the sump. Make sure to use the suction cup mount provided with the pump. Basically, the skimmer and pump do vibrate a bit, but this is okay as long as it is not directly contacting a resonant surface like the edge or top of your sump.
3. Gate valve modification makes it much easier to adjust the water level in the skimmer ( and therefore the quality and quantity of the skimmate )
4. There's a recirculation mod which is supposed to increase the skimming efficiency by increasing the air input and improving contact time. You also need to do the "feed pump mod" with this one, which just adds a feed pump to move water into the skimmer now that the original feed pump has become a recirculating pump instead. Some people do an elbow mod which uses a 90 or 45 elbow to try to redirect the pump output inside the skimmer and increase contact time.
A lot of people recommend
www.asmskimmer.com as the place to buy them.
I just received and hooked up a G4+ last night with the gate valve mod - the thing is much bigger than I expected, but seems reasonably well built, quiet in operation, and so far is making a lot of bubbles but not much else.
--Albert
