Return Line Size for ~400 Gallon Tank

[kados]

Question for the monster tank builds out there (actual experience please)..

What size PVC return lines are you all running?

I am planning a future in-wall peninsula plumbed layout to replace my 200g system that I currently have in the same spot now and want to see if anyone has 1.5' lines in their returns.

My current system has 1" PVC return lines with (2) Neptune COR20 pumps that support a manifold for media reactors and 50W UV.

I would like to run (1) Abyzz A200 with 1.5" returns on next build.

Dimensions: 72" L x 30" W x 48"H.

This will also be a fish only system and 4ft in height.

 

[blaxsun]

My 200-gallon system has 3/4" return lines which max out @2,160gph. 1" is 3,480Gph, 1.25" is 6,000Gph and 1.5" is 7,560Gph. Sounds like it will be an amazing build!

 

[kados]

My 200-gallon system has 3/4" return lines which max out @2,160gph. 1" is 3,480Gph, 1.25" is 6,000Gph and 1.5" is 7,560Gph. Sounds like it will be an amazing build!

Thank you for providing the flow rates! 1.5" will definitely be plenty. I planned my existing build around everything 1". Since I'll need to upgrade my sump, I figure have drains and returns all 1.5".

 

[blaxsun]

Thank you for providing the flow rates! 1.5" will definitely be plenty. I planned my existing build around everything 1". Since I'll need to upgrade my sump, I figure have drains and returns all 1.5".

Going with 1.5" certainly simplifies things for all your valves, adapters, etc. (since you can easily mix and match where needed) Chances are the potential flow will far exceed what the pumps can deliver anyway.

 

[SPR1968]

I used 32mm (1.25inch) return on my large system connected to an A200 run at around 86%

I attached a 50mm short length of pipe (4 inch fitting) to the inlet on the pump to help with water inflow (read it somewhere on the instructions)

I use the 86% because above that and near full power it doesn’t make much difference to the flow rate (check the graph) so didn’t see the need to max it out.

Apart from the 2 down pipes which are larger at 40mm, everything else is 32mm to standardise it.

 

[kados]

I used 32mm (1.25inch) return on my large system connected to an A200 run at around 86%

I attached a 50mm short length of pipe (4 inch fitting) to the inlet on the pump to help with water inflow (read it somewhere on the instructions)

I use the 86% because above that and near full power it doesn’t make much difference to the flow rate (check the graph) so didn’t see the need to max it out.

Apart from the 2 down pipes which are larger at 40mm, everything else is 32mm to standardise it.

I just looked at your build thread. Absolutely terrific! That is a beautiful reef tank.

Thank you for the feedback. I'm still very early on the planning but really want to get this one right. Here's an older picture of the current system from a couple years back. More rock and caves have been added since then and a paint job on the cabinetry. Everyone's growing.. The new build would land in the same spot but 8" wider and 20" more height. I recently sold a 36" in height tank and loved the tall view.

 

[Yanos]

My 200-gallon system has 3/4" return lines which max out @2,160gph. 1" is 3,480Gph, 1.25" is 6,000Gph and 1.5" is 7,560Gph. Sounds like it will be an amazing build!

No chance. Single 1.5” will do only 2000GpH max

 

[blaxsun]

No chance. Single 1.5” will do only 2000GpH max

Those are the "posted" numbers, but I suspect you're correct.

 

[C_AWOL]

1.5" returns are going to be large enough to accommodate virtually any pump you would want to use. For lower pressure dc pumps the larger ID also helps them handle head pressure losses better as well.

1.25" returns while a common output size for a number of larger dc pumps would be more "sensible" the bulkhead price and availability makes the upsize of 1.5 extremely worth while.

 

[reef_ranch]

I run a 1.5” return line with an Abyzz A200. I wouldn’t go smaller. In order to take advantage of all the potential of the pump you’ll need to go with a 2” drain.

 

[SPR1968]

I just looked at your build thread. Absolutely terrific! That is a beautiful reef tank.

Thank you for the feedback. I'm still very early on the planning but really want to get this one right. Here's an older picture of the current system from a couple years back. More rock and caves have been added since then and a paint job on the cabinetry. Everyone's growing.. The new build would land in the same spot but 8" wider and 20" more height. I recently sold a 36" in height tank and loved the tall view.

Thank you, and your current tank looks nice, especially the aquascape.

You can use whatever pipe size you want, both are fine with the Abyss A200. Mine feeds a UVC, reactor, chiller all from the same return pipe which also feeds the main display, from just one return pump without any issues, and all in 32mm.

Good luck and enjoy the planning and then the build it’s very enjoyable.

 

[Yanos]

Im running two of the reef octopus varios 8 pumps as I wanted to pass the water through my sump ten times per hour and I thought my 1.5” pipe will handle it. No chance. I run both pumps on the minimum setting.
After plumbing bends and head loss I’d say 2000 GpH is the max my plumbing can handle