Plumbing display and frag tanks together

Wes · May 28, 2018

Hello all! Hopefully a quick and easy plumbing question. I am hooking up a 40 gallon frag tank to my 200 gallon display and running a Vectra L1 that I want to use to feed them both with.

I know there is a bunch of discussion on how to plumb this type of set up and I know the best way to handle plumbing the frag tank with the display off a single pump is simply using two valves to control the flow to each but would a single valve be ok?

In the first diagram attached, would a valve where the red X is work to regulate the flow into the frag tank and simply allow the rest to go to the display or might no water make it to the frag tank at all?

The reason I want to do this is I have limited space where the output to the display tank is and can’t put a valve there so to make the shortest run possible I can only use one valve.

My only other option would be to T it off under the tank and have two independent vertical runs each with their own valves but i am concerned about flow loss and the additional complexity of the plumbing. See the second diagram.

Thanks!

First diagram - Direct plumbing w/ 1 valve

Second diagram - independent plumbing w/ 2 valves

User · May 29, 2018

If the display tank is higher than the frag, you could gravity feed a portion of the overflow to the frag tank

Brew12 · May 29, 2018

Wes said:
Hello all! Hopefully a quick and easy plumbing question. I am hooking up a 40 gallon frag tank to my 200 gallon display and running a Vectra L1 that I want to use to feed them both with.

I know there is a bunch of discussion on how to plumb this type of set up and I know the best way to handle plumbing the frag tank with the display off a single pump is simply using two valves to control the flow to each but would a single valve be ok?

In the first diagram attached, would a valve where the red X is work to regulate the flow into the frag tank and simply allow the rest to go to the display or might no water make it to the frag tank at all?

The reason I want to do this is I have limited space where the output to the display tank is and can’t put a valve there so to make the shortest run possible I can only use one valve.

My only other option would be to T it off under the tank and have two independent vertical runs each with their own valves but i am concerned about flow loss and the additional complexity of the plumbing. See the second diagram.

Thanks!

First diagram - Direct plumbing w/ 1 valve

Second diagram - independent plumbing w/ 2 valves

Unfortunately, that wont work well. You would have very unstable flow rates through each line unless you were pushing the pipe diameter near its maximum flow.

Wes · May 29, 2018

Brew12 said:
Unfortunately, that wont work well. You would have very unstable flow rates through each line unless you were pushing the pipe diameter near its maximum flow.

If I was pushing it near it’s maximum at the display tank outlet? Which I guess would cause some backflow and make it direct water to the frag tank?

I will be using 1” plumbing all the way up, would reducing to 3/4” loc line on the displays outlet be enough?

Brew12 · May 29, 2018

Wes said:
If I was pushing it near it’s maximum at the display tank outlet? Which I guess would cause some backflow and make it direct water to the frag tank?

I will be using 1” plumbing all the way up, would reducing to 3/4” loc line on the displays outlet be enough?

I'm not sure. It might be enough. I would worry you would end up with flow oscillations and that you wouldn't be able to dial in your overflows to keep them quiet.

Livinlocal · May 29, 2018

If you’re frag tank is lower than your display, you will need a check valve to stop the back flow from your display into your frag tank, which would cause a overflow out of your frag tank.

If I were in your shoes, I would personally do two ball/gate valves and two check valves. You could get away with using one ball valve at your frag tank, but then your display pressure will be solely dependent on the flow restriction to the frag tank. You can get the frag tank to flow perfectly, but then you will be stuck with whatever pressure is going into your display. What if it’s too much pressure? If it’s too much pressure going into your display, and your crack tank is perfect, that’s when the extra ball valve will come in to slow the water pressure down. Granted that’s only if your pump is strong enough. With having two check valves, you will ensure that there’s no back syphon from the display into the Frag tank, and no back syphon from the Frag tank into the sump. A lot of people are against the check valves, but unless you put some sort of siphon relief, you will get backflow.

Livinlocal · May 29, 2018

Another thing to keep in mind, at the intersection I circled in orange would be a problem if you only put a valve going to the frag tank. With a T fitting in that formation, the water will follow the path of least resistance, and will go straight into your display. Even without a ball valve on the frag tank, I highly doubt very much water would even make it to the Frag tank with that intersection.

Livinlocal · May 29, 2018

And with this configuration, you would not be able to use a check valve between the Frag ank and display because it would conflict with the direction of water flow, being the Frag tank is lower then the display.

rocsec1 · May 29, 2018

I ran the drains separately to the sump from display and frag. I used a manifold for,the return to both of them.

Norcalreef · May 29, 2018

Why not just run a second smaller pump for the frag tank? I plan to do a frag tank next to my display once I get all my fish qt. Will just have it be it’s own separate pump and plumbing.

rocsec1 · May 29, 2018

For me the idea was save space in the sump,
I have a fishhroom so mourning a manifold above the sump took up room I wasn’t using and saved sump space

Livinlocal · May 29, 2018

Sorry for the messy wires, I am in the middle of hooking up some new modules to my apex, but if you are going to split the line, you should have your T like this, so when the water flow hits the junction, it will split evenly into both directions, obviously that also depends on the path of least resistance, which is why my frag tank supply line is just a little smaller. I have a 1 1/2” line feeding my display, and 1” to my Frag tank, that gets stepped down to a 3/4” to help control the flow.

Livinlocal · May 29, 2018

Rakie · May 29, 2018

I just did this the other day.

I put a T on my displays return. I put on a gate valve to let in just a little water (don't need high turnover). I drilled the frag tank and filled it JUST barely enough to actually overflow into my one sump.

Very simple. Works easy.

Wes · Jun 4, 2018

Thanks all, I guess I’ll have to go with two valves. I’m gonna try and see if the compact deluxe style valves will fit up top

Wes · Jul 7, 2018

Well, took me a month but here is a video showing my roughed in plumbing. Thoughts?

Rakie · Jul 7, 2018

Wes said:
Thanks all, I guess I’ll have to go with two valves. I’m gonna try and see if the compact deluxe style valves will fit up top

Why will you have to go with two valves? I showed you you literally only need one tee'd off your return. The valve on your overflow is a separate issue.