DIY Sump / Closed Loop

[kbolick]

Is there any set way of determining the size of the sump/overflow for a tank? How many gph the pump/overflow should run, etc? I have a sump already, but I would like to build another and a closed loop system, but have no idea how to determine the capacity, etc.

[Geoff]

i will see if i can hunt down the formula for overflow length to volume ratio. there is a handy calculator out there also.

a closed loop will not use an overflow, if it is a true closed loop. it will be completely sealed from any air. an overflow counts as air. this is why most closed loops are drilled and all of the holes, both inlet and oulet are below the waters surface.

the way overflows are designed the limiting factor for total flow is the drain size. what kinda flow are you looking to get? with a little more info i am sure we could get you started.

G~

P.S.-where in NC?

[kbolick]

Right now I have a 55 gallon with two powerheads and a sump for a 75gallon with a 800 gph pump. I want about the same amount of flow, maybe a little more. I am hoping to upgrade the tank to a 75 gallon this year so obviously I will need a little more flow than what I currently have.


Charlotte, NC

[Geoff]

here is a calculator for figuring that out.

if you are going to be getting a new 75 then i really would consider getting it drilled for a closed loop system. depending on the store, getting the holes done will be about the same price as getting another overflow. are you going to be getting a RR tank? these have pretty large overflows, but they will not handle the flow that you may want.

what do you want to put in the tank? i am kinda of a flow junky, so i want to make sure you really need that much flow.

G~

[kbolick]

Just soft and hard corals... and fish.

[Geoff]

Nikki has about 1400gph in her predator reef. pretty much what you have described. i think this is a pretty good amount of flow. you could go up some more, but it seems plenty.

she has 1000gph in a closed loop hung over the side. the rest is from the return pump. i believe in just having enough flow through the sump that gets cycled through the skimmer.

G~

[hankstanks]

You mentioned a closed loop is completly sealed from air. Dose this mean the tank has to be covered?

Whats the purpose of a closed loop system vs. a sump system. Is it the flow rate?

This sounds like something I want to mess around with. I am building a new 90 or 120 soon (Starboard) and have been tossing around the idea of a closed loop.

It will be all LPS, and Softies. a few small fish

[Geoff]

all of the plumbing for the closed loop needs to be sealed off from letting any air get in. does not mean the tank needs to be sealed off.

when using a closed loop you do not need to worry about if the overflow can handle the amount of flow the pump is returning. also the greater the flow through the sump the greater the chance for bubbles in the display. there are several different ways to do closed loops. most people opt to drill their tanks for the inlet and the outlets. yardboy has the type of closed loop system that i think is the best.

Nikki has an over the side CLS, and i have 2 above water line sealed CLS's.

mine:



G~

Nikki's-follow the pipes form the Quiet One pump.

[yardboy]

Geoff, the drain calculator you linked to is misleading. I only have a 1" drain with a Mag 18 and there has been no cavitation. The calculator recommends a 1.75" hole. Now I know that due to some elbows in the system I'm not getting 1800gph, but 1.75"! That's a BIG hole in your tank!

[Geoff]

the calculator i think is used for gravity feed through X sized pipe. i do not think it calculates what the maximum amount of water that can be pushed through a pipe actively.

G~

[dwall174]

Originally posted by Geoff
the calculator i think is used for gravity feed through X sized pipe. G~

I believe Geoff is correct! Here's a list of gravity flow rates for regular size PVC!

Flow Chart

1/2 " PVC
3.5 GPM
210 GPH

3/4" PVC
6 GPM
360 GPH

1" PVC
10 GPM
600 GPH

1 1/4" PVC
20 GPM
1,200 GPH

1 1/2" PVC
30 GPM
1,800 GPH

2" PVC
60 GPM
3,600 GPH

2 1/2" PVC
100 GPM
6,000 GPH

3" PVC
175 GPM
10,500 GPH

[Geoff]

where did you get that chart!!!

thanks for finding that,

G~

[yardboy]

Yea, that Mag 18 really sucks!
Now I think you know why I was so uncomfortable with 2- 3/4" discharges on a 1" intake! My 20L has a 1" gravity discharge and it drives me nuts with its feeble drain. (due to elbows, I doubt it even gets 10gpm)
Man, when you're so in the dark, every tiny light is an epiphany!

[dwall174]

Originally posted by Geoff
where did you get that chart!!!G~

I can't remember who I got it from? It was from someone here or over on RC!
HERE'S another link that has some goog plumbing information.

[dwall174]

There's also a lot of imformation on plumbingsupply.com Just click on the PVC link then look for "PVC FAQ"