Easy quick connect when doing a water change. Use the pump to remove water. Later I removed it because the valve started to leak. So I just un did the union on the line going to the skimmer. It help if the union is high, so you are abouve sump level. Doesn't make a mess this way.

Lee

Guessing that's the one off the green pump.

Wondering the purpose of the line T'ing off the black pump (no valve) going into the overflow return area, other leg is labelled to tank.

If I'm understanding the labelling, wouldn't about half your return pump flow is going back to the sump.

By the way, nice neat layout.

Close, the recirc line of the black pump had a 1" to 1/2" reducer on the end, no way to tell from the picture. I had to do this because the overflow pipes I had restricted too much flow. They were J&L style with 90 elbows and screens. So I had to reduce my return flow. I don't like using valves, if it ever got to the wrong position my tank would have over flowed. I later changed the overflow and removed the recirc line. Thanks for the comments. It will be a sad day on Sunday when all my best designed equipment leaves.

Lee

SOLD.