I first purchased the Ocean Motion squirt 3 years ago after not being able to find anything that would alter water flow without reducing the volume of out put drastically. Mechanisms like the squid cut down on volume more than I feel is acceptable for a reef tank. Ocean motions uses a drum that is impregnated with magnets that are slowly turned by a motor. The unit is very will built with the housing being cell cast and each outlet threaded for 3/4 inch pvc fittings. You will want to put unions on all of the 4 connections because putting a fitting on it that can't be undone will make the unit worthless. You must adhere to the recomendations that you not use the squirt with flow in excess of 1000 gph because the magnetic pull on the drum is not enough to overcome the force of the water. I currently have a dart on it but it is backed down by 60% or more. I had to replace the drum just recently which was $20 because grooves had worn in the plastic and was causing it to hang up inside the housing. I would strongly recommend using the Super Squirt as the minimum ocean motion product for flow, it is a bit more expensive but you will never have to worry about back pressure and flow. The super squirt can be ordered with several different configurations of outflow which is nice. Fisher12 uses the largest ocean motion which is the 8 way (which I plumbed backwards for him, he will be happy to tell you about it) on his 400 gallon and the 4 way on his 200 gallon. The ocean motion is best used with a drilled tank witch is a hazard in itself but can be run with the inlets over the top but it is alot of plumbing that is in the way. I have not found a real downside to using the ocean motion, perhaps that the flow alternates in sequence and is not truly random can be seen as a downfall but I don't consider that to be. It is a dependable well made product that I would highly recommend. Super Squirt Squirt
