overflow capacity...

tank is being drilled, dont know how close to the top those bulkhead fittings will be, so I dont know exact displacement of water that could leave the tank during power off. Im guessing 3-4 inches from top of tank right? Im doing the math in the sump right now about to get the panels cut. What im wondering is how much water depth would a mag drive 9.5 need to function? The pump itself is 4.5 tall, and the intake a bit lower... can I just make the bubble trap 5" tall before the pump and just cover the pump.. Maybe this is more of a hardware question.. If the bulkhead fittings are drilled at 4" I would probly need 10-11 gallons overflow.. I got this 20 gallon tank im not using.. gunna be close. Hopefully the holes are around 2" heheh

 

Total maximum drainage:

3/4"-700 gph.
1"-1000gph.
1 1/4"-1200gph.
1 1/2"-1500gph.

Dersa/durso style overflows will allow up to 20% higher maximum flow over a standard standpipe.

 

I'd not drill any hole in the top of the tank I always drill mine low and put a vertical overflow box then I use a stand pipe behind the overflow to control the distance the water through the overflow has to fall to drain to the sump limits the splashing sound and if you just try to use the bulk heads drilled into the top area of the tank you will never have a totally clear skimmed water surface and you will not be able to control the water line as it will be lower then the top band of the aquarium. I would suggest that you go look at a reef ready system and notice the overflow column boxes . There is a reason its done like this.

 

i forgot to mention that guy whos doing it has some premade covers for the bulk head fittings and they have small slots at the top of the water line and are sealed to the back of the tank around the fittings.. Hey i just answered my own question. The slots in the covers are only like an inch long.. so it will only drain down an inch = 2.49 gallons.. cool..
8)

 

Depending on several factors there is no way to tell for sure what the drain off will be to the sump if pumps go off but 2.5 Gals sound a little shy unless its a small tank like 25 gals or so ? As for depth for the pump ? it will seek its own level once you fill the tank to the overflows and then enough in the sump to get pump going. I'd set some sponge under the Mag power head to hold down vibreation sounds on the sumps bottom .. and I also put a MIP street 90 into the intake fitting of the Mag and have it looking somewhat downwards to pull right off ot the bottom few inches of the sump.

 

ahh good idea!

 

I would not go to all that bubble trap work either unless you just want to ? If you pipe it correctly then you won't have any bubbles to deal with . How many overflows and drains will be used on this tank and how large is the tank ? mag 9.5 may be more then you want or need ?

 

55 gal. two 1" overflows, 20 gal sump/fuge, skimmer. I decided to go with a mag7 instead. I built the sump (with bubble trap) and I have an overflow capacity of around 6.5 gallons.. the main tank does like almost 4 gal when it drains. plus 1 at most in the skimmer, should be good. ;D