Sump Plumbing

[Dale]

Hi Mark,

Some thoughts regarding your design:

Placing a union close to your return pump will allow you to switch it out easier if it fails.

It is good to consider pipe diameters vs flow rates but the most important thing is placing a valve in your return pump line to allow you to regulate the return flow and prevent overwhelming your external overflow box and drain lines.

You only need one valve in your drain line. This should be on the line feeding the refugium. The other two valves are overkill and shouldn't be used as they pose a risk of restricting the drain line so that it can't keep up with the return pump.

While your sump layout may work fine, it is a little complicated. Having the overflow drain and skimmer so close to the return pump adds to the problem of micro bubbles drawn up into the display. It also means splitting the drain line in two to feed the refugium. A more trouble free set up would be (from one side to the other):
Single overflow drain line into sump
skimmer compartment
Set of baffles
refugium compartment
Single baffle
Return pump compartment

Those are just my thoughts. The fun thing about this hobby is that there are many ways to express ones creativity. Have fun!