Confirming drain size

[Nstocks]

Hello,

I'm currently designing my first aquarium and looking at ways I can make the weir box smaller, but will full functionality. It seems most reefers use 1" pipework for the drains, however after looking at some calculations, 20mm is more than adequate for my tank.

Volume is approx. 135L with a 50L sump.

There will be two 90 degree elbows, one ball valve and one check valve. Height to top of return line in aquarium is 4 feet. Image below is using a 1250 litres per hour pump.


I've put in 200 gallons to the reef central calculator and it gave me:
Recommended minimum drain pipe diameter = 0.58 inches (15mm)
Recommended minimum linear overflow size = 3 inches


Does this mean 20mm is enough? (though internal diameter is around 18mm). I will be using twin standpipes and one return line.

Thanks

 

[Nstocks]

Any comments on using 20mm drain sizes?

 

[ca1ore]

Any comments on using 20mm drain sizes?

Yes, 3/4" is too small! There's a reason 1" is considered a minimum for open channel drains. Any smaller and the practical capacity falls significantly and they get noisy at relatively low flow rates. Plus, 200 gph is low for a 135 gallon display - you want to be targeting 400-500. If you choose to go with a siphon drain system, the siphon side can certainly be 3/4", but the open channel must be 1" or bigger.

If u want a smaller profile, do an external scupper box with a low profile skimmer box inside the tank.

 

[SGT_York]

Liters not gallons.

I would go herbie not two durso's and I'm sure you'll do fine with 200. if you want to keep the durso style overflows go 1". you'll get the slurping with the ~3/4" pipe at 200 GPH.

 

[Nstocks]

Yes, 3/4" is too small! There's a reason 1" is considered a minimum for open channel drains. Any smaller and the practical capacity falls significantly and they get noisy at relatively low flow rates. Plus, 200 gph is low for a 135 gallon display - you want to be targeting 400-500. If you choose to go with a siphon drain system, the siphon side can certainly be 3/4", but the open channel must be 1" or bigger.

If u want a smaller profile, do an external scupper box with a low profile skimmer box inside the tank.

135GALLONS? Nope, 135 Litres here :rollface:

20mm pipe can handle 1200lph, this is more than enough right?

 

[Nstocks]

Liters not gallons.

I would go herbie not two durso's and I'm sure you'll do fine with 200. if you want to keep the durso style overflows go 1". you'll get the slurping with the ~3/4" pipe at 200 GPH.

We must have hit "submit reply" at the same time!

Twin standpipes (open ended) herbie don't produce gurgling do they, since one is many inches below the water level.

 

[ca1ore]

Yeah, sorry, that's what you get from trying to do too many things at once ...... and too much bouncing around between metric and non metric .... anyhow, a herbie setup will be silent if you run it right. I still wouldn't run smaller than a 1" open channel myself .... but that's just me.