Bulk Head size vs return into the tank

[andrewchiles1]

Howdy R2R members. I have a question for the club, it has been established that I will be placing a 2 inch bulk head on my 3 inch drilled hole for my overflow box. So with a 2 inch line draining into my sump, what size return line do I need to make sure I do not overflow my sump. I watched a video that says I need to go 2.5 on the return, but I am not sure. Please let me know. thanks Drew

 

[cromag27 Verified Sponsor]

I like 2 different returns in either corner. You could do 2 at 3/4". You don't want the return too large or else you'll lose pressure.

 

[Reefing Madness]

Your pressure pump is usually going to be able to overtake a gravity feed anyday. So, you could go with a couple 3/4 or a 1" would be more than enough.

 

[AZDesertRat]

You will not overflow your sump ragardless of the size of the standpipe. The height of your standpipe or the level of the teeth/weir on your overflow box. Once the tank level drops to that point the siphon stops.
It is the return pump that determines the overflow rate, the standpipe or overflow will match itself to the GPH of the return.

This might help you to understand how it works a little better:
Melevsreef.com | Acrylic Sumps & Refugiums

 

[andrewchiles1]

Do you recommend having the drain lines meet in a Y and then drop into the sump? If I do drill the other side of my tank, I was thinking about having both drains meet at a Y junction and drop into the sump. The other option I was considering was a 3 foot overflow box that would help pull down water with greater surface area and a single return. What are your thoughts please?

 

[andrewchiles1]

what a great point, I should have realized that with a gravity feed, the only factor in the return is the pump. Thank you.

 

[AZDesertRat]

If I had dual overflows which I do not in my 100G I would keep them separate. When you start adding elbows and fittings then combining the flows from two into one you start adding head or resistance to flow which is not good in a gravity situation.

 

[cromag27 Verified Sponsor]

When I do builds with multiple drains, I always keep them separate.

 

[Psyko]

+1 on separate drains. Y-ing the 2 drains would reduce the flow capacity to that of the pipe at the end of the y. Would be like having one drain as far as flow is concerned.

 

[andrewchiles1]

Thank you all for the responses. As my tank comes together I will send pics. I do have a dream of a filter less tank.
My sump will be about 36.5 gallons based on my space under the tank. All in all this I a huge DIY project for me. I will continue to ask questions and look forward to yall's input. best regards Drew