Step down Overflow Plumbing

[Richardsonic]

I'm setting up my first reef tank and I just starting the process of plumbing. I've run into what may or may not be a problem. It's 220 gal tank I drilled for a Modular Marine 24" overflow (purchased new). The size of the three drain bulkheads in the external box look to be 50mm (or 1 7/8") slip fittings. However, the used Bashsea sump I purchased has 35mm (or 1 3/8") openings for the drain line holders. So if I run PVC lines to my sump, should I just avoid the holders (and the accompanying filter socks) so I maintain the higher capacity that comes with a fatter pipe? Or do I down-convert the drain line to the smaller size and take advantage of the holders and filter socks? It seems like the only issue is whether or not my hourly turnover is impeded dramatically by using the smaller drain outlet in the sump. My plan is to run a bean animal with a gate valve on the full siphon. Any insights are appreciated.

 

[JoshH]

I'd maintain the 1" drain pipe all the way into the sump and just bore the holes in the sump bigger to handle the proper sized bulkheads or remove the bulkheads in the sump and run the straight pipe into the holes with no bulkheads atall.

 

[Richardsonic]

I'd maintain the 1" drain pipe all the way into the sump and just bore the holes in the sump bigger to handle the proper sized bulkheads or remove the bulkheads in the sump and run the straight pipe into the holes with no bulkheads atall.

Is 1 7/8" considered a 1" drain? The sizing of the plumbing is somewhat confusing especially considering the schedule 40 vs schedule 80 thing.

 

[Richardsonic]

After a quick trip to the local hardware store it appears that 1 7/8" opening is referred to as a 1 1/2 inch pipe. I'll see if there is room on the existing ledge to drill them out to the right size.

 

[JoshH]

Is 1 7/8" considered a 1" drain? The sizing of the plumbing is somewhat confusing especially considering the schedule 40 vs schedule 80 thing.

A 1 7/8" hole in glass or acrylic is designed to fit a 1" bullhead that 1" PVC pipe runs in to. A 1 3/8" hole is designed to fit a 3/4" bulkhead for 3/4" PVC pipe.

 

[Richardsonic]

I see. The dimensions I gave were for the inside diameter of the bulkheads not the hole the bulkheads themselves sat in. It looks like there is adequate room to drill out the holes where the bulkheads in the sump sit. Especially if I don't drill for the larger bulkheads and just enlarge enough for the drain pipe alone.

 

[JoshH]

I see. The dimensions I gave were for the inside diameter of the bulkheads not the hole the bulkheads themselves sat in. It looks like there is adequate room to drill out the holes where the bulkheads in the sump sit. Especially if I don't drill for the larger bulkheads and just enlarge enough for the drain pipe alone.

Ahh I see, confused me for a minute as pipe size measurements are not based off the outer size of the pipe (Inside of a slip fitting) but the rough internal size of the pipe itself. As you can see, these measurements can sometimes overlap with bulkhead hole sizes. So you are looking at 1 1/2" PVC pipe for your drain and roughly 3/4" for the sump. I would definitely try and maintain the 1 1/2" pipe throughout the drain setup however you achieve this is up to you :)

 

[Richardsonic]

Will do. Thanks Josh.