Help: Question about return line size

[tuanp]

I bought a used 120gal acrylic setup a while back and finally got to set it up. The tank is 4' x 2' x 2', so it's tall. It has built in center overflow. But it has only one 1" bulkhead for the drain, and only one 1/2" bulkhead for return; both are inside the overflow box through the bottom. Additionally, there's only one 1/2" bulkhead on the side of the overflow for the return into the main tank.

My question: is the 1/2" return too small for this size tank? and is that narrow diameter too restrictive for the return pump? (I have an Iwaki MD30 that I plan to use for the return.) I'm just wondering whether if I would need to increase the return line size. Apparently the tank was plumbed like this by design, so if there's any way to make it work as-is I'd be relieved, because I'd hate to have to drill another hole or something because I don't have experience with that and don't want to risk damaging the tank.

Thanks in advance for any advice or suggestions.

tuan

 

[mfinn]

I would use both of the bulkheads that are already drilled as drains.
Then plumb the return over the top of the tank.

 

[tuanp]

Thanks Finn. That's a good idea. Since this is an acrylic tank and it has only two big openings in the middle (which have lids that close completely), I'll have to run the return through the two round holes intended for power cords/ heater/etc. But this would be better than having to drill the tank.