Drain Diameter Question?

Ok so I plan to drill a 150 gallon DT soon to serve as my overflow. Just trying to determine what size bit to buy. I do not have a constructed sump yet but I do like the design from melevs reef Melevsreef.com | Acrylic Sumps & Refugiums (I hope to start that build within the next few weeks.) I also do not have the return pump ....yet. But in my endless searches to find one I think I have narrowed it down to the Reeflo Dart (2428 @ 6').?.? (any thoughts??)

My question is in determining diameter of bulkheads to install as overflows to the sump

My initial thought is to run two drain lines (one from each back corner) to feed the sump (and skimmer). Is there a recommendation for hole size to be drilled? (I've performed a search on here and could not find a thread)
Just to fill you in, i do not plan to run any type of internal pump in the DT (That is the reason for a high GPH return pump). Just trying to establish good flow.

Thanks in advance !! You all rock

 

So your tank is not drilled now right with overflow boxes?

What type of overflow are you putting in?

 

Tank is not drilled. Its sitting in the garage starring at me. I did not plan to use an over flow box, just bulkheads with 90°'s facing upwards to collect the water from inside the DT. I do have two seperate overflow boxes (wier) that have the u-tube's that i'm not using, looks like 1" bulkheads in them. I just didn't want to use them if i didn't need to. Is this a bad idea?

 

How custom do you want to get? Have you ever heard of Herbies or Bean Animal overflows? You have to have some sort of weir or the tank will drain down to the point of the drain. (Sorry if I'm stating the obvious)

 

No worries, i'm not planning to make it anything special, I just prefer the "clean" look. I guess my goal is to eliminate boxes, cords, pumps etc from being displayed in the tank. Although the return spouts and overflows will be shown. And yup you're right, they are the Weir boxes, one's got an 1-1/4" drain and the other is 1" drain tube. I have not heard of Herbies or Bean Animal overflows i'll do some googling tonight. I plan to paint the backside to hide plumbing and what not.

 

Here you go

http://www.3reef.com/forums/i-made/my-herbie-overflow-write-up-pics-beware-60239.html

 

Great thanks, thats exactly the thread my search took me too last night. I'll see about drawing something up. It seems though in the Herbie style there is restriction required to keep water level above the drain in the plumbing. I may be thinking too deep into this but would this require larger holes in the DT, like 2"?? Well actually 2" now seems too big, maybe 1.5 sounds about right?

 

Glass-Holes uses 1.5" bulkheads on their drill through overflows. They have one they rate at 1500GPH that uses 2 holes.

 

I think your plumbing size question has been answered (and +1 to the herbie method) but I really think you should reconsider the no-internal pump issue. For reefs most people recommend at least 20-30x the display tank volume for internal circulation. I would aim for at least 4500gph of internal flow, more if you want to keep SPS eventually.
Even if you get 2400gph out of the dart, which I think is optimistic since you'll probably want 2 returns so you don't just have one big jet blasting into the tank. You will probably end up with dead spots in the tank where detritus is going to collect which makes maintenance much more of a chore.
If you don't want internal powerheads I would look at doing a closed loop system so you don't lose so much power (and waste so much electricity remember it will be on 24/7) fighting head loss in your return plumbing. You also may run into problems with noisy plumbing and a noisy sump as well with that much water rushing through it.
Closed loops are definitely used regularly and to me are the only way to get good flow without using powerheads in the tank but they do require more holes be drilled in the tank and some fancier plumbing, they also tend to add more heat to the tank than powerheads because they're less efficient with their electricity.

One more thing to consider with your drains is that without an overflow/surface skimmer box you will be much more prone to flooding if algae/snails/dead fish/detritus etc get clogged up in the drain plumbing/screen. Having something to hide the plumbing in the tank adds another layer of protection to clogging the drains.

 

To not have any plumbing in the tank, then you are really talking about a external overflow. I mean, I don't want to send you on some pie in the sky super duper best design ever..... but there are tried and true ways of doing what you want.

Does not seem worth it to drill a tank and still have siphon overflows. You need a weir or overflow box in the tank...which you do not want. That leaves you with a external overflow, or a Calfo coast to coast overflow.