Sump Plumbing

[Alaeriel]

We almost got to plumb our 200 gallon tank this weekend!
As it turns out, the previous owners just sawed through the soft plumbing instead of unscrewing the bulkheads and removing it all in one (reusable) piece. We've largely isolated the pieces that we'll need to get the thing plumbed, but there appears to be a random bulkhead sealed to the side of the sump about three inches from the bottom. It's got a barbed connection for soft tubing, but there isn't enough space for an ATO tank to be placed on that side (the sump has a plywood barricade inside the stand). [See Diagram]
From the remaining tubing, it appears bulkheads A and B are for the drain siphons, and hole C has a double barbed connector with a T-splitter for the return pump. Bulkhead D has an obtuse elbow joint with a short PVC connector which transforms into the barbed adapter through its bulkhead. I can't seem to find any other models with a Quick-Drain option like this (240 gallon system or Basement Pond system?), so hopefully someone knows what it's meant for!

 

[lapin]

D might have been used for something remote.
Could have had a second pump in the return chamber. This would push water thru the "D bulkhead" and feed reactors or a UV.
It could also be used for an external return pump.

 

[JumboShrimp]

Very hard to say, because it’s only limited by the imagination. Maybe the previous owner used it as a quick/drain port; or ran it to a secondary sump, etc., etc. I’d plug it, and not think twice about it... full steam ahead! Best wishes.

 

[Saltyreef]

Its a connection for an external sump pump.

 

[Alaeriel]

Awesome, the bulkhead appears to be sealed to the tank, so we'll probably plug it with a piece of dummy tubing and if we ever need to add a dosing pump later, we'll use that spot. Thanks, everyone!