Plumbing questions

[A-Aron]

I just bought this used tank and need to plumb it for a sump. It is a 3’ x 4’ x 2’ acrylic tank, it was listed as 200 gallons but I’m thinking that was a bit exaggerated. I am wondering the best/safest way to plumb the sump based on the details below.

It is set up as a peninsula style with an overflow in the center of one of the 3’ sides. Within the overflow it has two holes drilled at the bottom. One hole is 2.5” diameter and the other is 1.5” diameter. on the top of the tank, there is 7” wide bracing of acrylic around the entire top as well as down the center, looks to be a single piece of acrylic with the two access squares cut out for fish/rock access. The frameabove the overflow is open and there are 1.75” holes drilled iN each corner of this top framing. All acrylic is .5” thick.

Current equipment I have on hand is all used but will hopefully get me started. I have a Trigger Emerald 34” sump, Vertex Omega 180i skimmer, unsure on the return pump as it needs to be cleaned up to read the model information. I also have the older style Aquaric Life Hybrid 48” t5 light fixture that I may add LEDs to in the future.

Appreciate equipment suggestions as well and am excited to start on my first saltwater setup.

 

[tippin.turtle]

My guess is this: A 2.5 inch hole was used to accommodate a 2 inch bulkhead and was used as the primary drain. The 1.5 inch hole was used for a 1 inch bulkhead as an emergency drain. The holes on top of the tank may have been used for a sea swirl or wires for circulation pumps.
Just a guess on my part though. Nice tank BTW...lol.

 

[A-Aron]

My guess is this: A 2 inch hole was used to accommodate a 2.5 inch bulkhead and was used as the primary drain. The 1.5 inch hole was used as an emergency drain. The holes on top of the tank may have been used for a sea swirl.
Just a guess on my part though. Nice tank BTW...lol.

Two drains makes sense, how would you run the return? Over the top? Appreciate the help and compliment!

 

[tippin.turtle]

The three holes in the top of your cabinet I imagine is for two return lines and the center being for electrical. I wouldn't think your return lines to be greater than 3/4 inch. I can't explain why your holes in the top of the aquarium are 1.75 inches other than the hole was for 3/4 inch loc-line and electric cables for circ. pumps. Another possibility could be that metric plumbing was used on the initial setup.
Perhaps explaing the 1.75 inch hole. I haven't had to convert my plumbing from standard fittings to metric; so I have no experience with that...lol.
So, I would use 3/4 pipe with with 90's and loc-line.

 

[ca1ore]

Holes in the bottom of the overflow are odd. A 2 1/2” hole will take a Sch40 1 1/2” bulkhead but a 1 1/2” hole will only take a 3/4” bulkhead. I’d probably over drill the latter to get it to 2 1/2” also. At 4x3x2 you’re looking at something approaching 160 gallons. A 3/4” bulkhead isn’t going to be much use as an emergency, so that’s what I’d use as a main siphon, with the larger bulkhead as your backup. The 1 3/4” holes in the top brace will take a 1” bulkhead so probably were used as dual returns.