Comments: I bought 6 sets of the Loc-line jets with the MPT ball valve for a distributed return around the tank. These works well, allowing great flexibility in aiming and controlling the water flow. The only problem I had was with the valves themselves. Some of them are very tight to turn. My fingers hurt after each time I turn them. Salt deposits do form onto these pipes above the waterline. Be careful when you knock the salt off that they don't land on your precious coral. One tip: you don't really need their tool to put the pieces together. They can easily be pushed together. Don't know about pulling them apart. Haven't tried it yet.