Return hole question.

[Krikit]

Hello. Im nearing to the point of putting all these months of research and lurking on here to test. lol I am putting together my first SW tank. Intention is FOWLR till established then start reefing. Its a 20H w/ another 20H sump. I have a glass-holes "Super Nano con Dientes Overflow Box Kit" enroute, a SEN 500GA sub/in-line pump and a koralia powerhead.

The overflow kit has a 1" bulkhead and glass-holes claims 300GPH. My question is should I drill for a 1" return or 3/4" and why?

I understand the constraints IRT to amount of and type of fish i am able to keep w/ a 20gl.

Thank you in advance for the help.

[SGT_York]

you'll get slightly better flow with a 1" return drilled, but both will work. (return means return from your sump not the drain to your sump)

[thegrun]

For a 20 gallon tank you would only want about 200 GPH to run through the sump maximum. Since a 3/4" drain will handle 350 GPH I would go with two 3/4" drain lines, one as a primary and the second as an emergency back-up.

[ca1ore]

I have dual 1" drains and a single 3/4" return on my 90 and it works just fine. The only mistake I made was not grinding the hole close enough to the top rim, so I get a lot of back siphon.

[Krikit]

Good info. Thanks all. One other question that poped in my head: roughly how much flow would i lose by adding a check valve to my return to prevent back siphoning? I'd imagine that it wouldnt be signifigant enough to concern myself with but I figured I should ask the question to those that know more than me.

Thanks

[thegrun]

Originally Posted by Krikit

Good info. Thanks all. One other question that poped in my head: roughly how much flow would i lose by adding a check valve to my return to prevent back siphoning? I'd imagine that it wouldnt be signifigant enough to concern myself with but I figured I should ask the question to those that know more than me.

Thanks

Most of us would not recommend using a check valve. In a saltwater tank it is just a matter of time before it fails. Salt and calcium deposits quickly render check valves inopperatable. If you rely on a check valve to prevent your sump from overflowing in the case of a power outage or when you turn off your return pump, you have a flood waiting to happen (research has shown that this failure is much more likely to occur while you are away on vacation or rushing to get your wife to the hospital for the birth of a child).

[JAnwyl]

thegrun "(research has shown that this failure is much more likely to occur while you are away on vacation or rushing to get your wife to the hospital for the birth of a child)." So true, Something bad happens at the most inopportune time.

[Krikit]

Originally Posted by JAnwyl

thegrun "(research has shown that this failure is much more likely to occur while you are away on vacation or rushing to get your wife to the hospital for the birth of a child)." So true, Something bad happens at the most inopportune time.

I've heard that this Murphy guy can be a vengeful SOB lol

And thanks for the check valve info. As a Submariner I'm slamming my head on my desk for not thinking about that. And I sure as heck dont want to add another item to my Preventative Maintenance Schedule.

[thegrun]

Most of us try to limit the amount of drain down water by drilling a small hole in on the side of our return (drill it at a slight downward angle so the water squirts down into the tank when the pump is on) that acts as a siphon break.

[Krikit]

Originally Posted by thegrun

Most of us try to limit the amount of drain down water by drilling a small hole in on the side of our return (drill it at a slight downward angle so the water squirts down into the tank when the pump is on) that acts as a siphon break.

Thats pretty ingenious!!

[thegrun]

Originally Posted by Krikit

Thats pretty ingenious!!

I wish I could claim it as my own invention, but its a trick that has been around for many years.