300g Tank: What size drain would you choose?

[Elegance Coral]

I have a dart pump running on my 300 with two 2" durso drain pipes. With no turns in the drain pipes, just straight down to the sump, the water level in the overflow is right at the top of the durso's. I would definitely go with two 2" drains and maybe a vectra L1 return pump.

 

[Chuk]

I would have two x 1.5" main drains

 

[GoVols]

@revhtree
How big (long) is the overflow?

Does your friend need at least two overflows?

 

[Mohammad D. ALMUTAIRI]

for so many reason a 2" is my choice.
I'd rather have the peace of mind if I ever wanted more overflow I can do it.
am building a 300+ G tank right now, and I'm going with 3x 2" with 1 primary and 1 secondary and 1 as backup or emergency

voting 2"

 

[Scott.h]

I believe 1.5" will naturally flow (without force) 1350 gallons per hour. So it depends on the return pump and head pressure. Personally I'd do two, whatever the flow need.

 

[Labridaedicted]

I'm running 2x 2" on my 180. With 2" you'll likely never have to worry about that being your choke point for flow values and they would take forever to foul to the point that you have much reduction in flow with standard return rates. I tend to overbuild things, though.

 

[Want2BS8ed]

Didn't realize we needed to give quantity as well. 3x 2" in a true BeanAnimal arrangement.

My 120g DT uses a ghost overflow copy with 3 1-1/2" returns BeanAnimal style. I have run 2,200 GPH (measured not just pump output) without mechanical problems. The limiting factor for me were the two 1-1/2" drains between the boxes of the ghost. There was enough flow that they drew air and gurgled. Wish now that I either had 2x 2", 3x 1-1/2" or an external overflow.

When my tank arrived it look like it had snuggled with a porcupine:

2x 1-1/2" holes for the ghost overflow
2x 2" holes for intake on the closed loop
6x 1" holes for returns (2x from sump and 4x for the closed loop)

 

[MightyMouse85]

I built my 360 with (2) 1.5in drains and only need 2 powerhead at 20% to turn the tank.

 

[Mark Gray]

I would use 1 1/2 inch but I would put 2 shadow overflows in I think so you would have 2 1/1/2 inch drains

 

[madweazl]

1.5" at full siphon (36" head height) will flow approx 4600gph; assuming the plumbing is only 80% efficient, you're still looking at almost 3700gph. No practical value in using anything larger than that.

 

[alanbetiger]

Two 1" drains in my 350. I don't have a high turnover (two mag9.5s for returns) so one would of been enough, but I have two sumps and it was going to be easier to have one drain to each sump. Plus the added bonus of having an emergency drain.

 

[TaylorPilot]

3 of the 1.5" is more than enough for 3000 GPH. If you do go with 2", make sure that you really do have close to 3000 GPH, or it may have trouble purging. Unlike with open drains, you can have too large a drain when utilizing a siphon. Although I don't think you would have a problem with 2", as long as you are close to the 3000 GPH, and design the drain using best practices. IE, no long horizontal runs, use 45s instead of 90s, keep the gate valve close to the outlet, and most importantly, make sure the drain only extends down into the sump water about 1". If you do all that, it should do great with either size.

 

[Danny_M5]

I have 1 1/2 on my 300g