Plumbing Triple Tank Set-up

[Cap'n]

OK, I have two 55gal tanks side-by-side and a sump underneath. The tanks are running independantly right now and the sump is not complete yet. I am planning on plumbing all three tanks in a series but I keep coming up against the problem of one of the overflows running dry because the other two tanks have slightly more flow. I really don't see how I can get all the outflow / inflow dialed in to match. Any easy solutions?

I'm almost at the point now to scrap this plan and simply have the two tanks share a common sump, but I think this will require adding even more equipment, and one of my main goals with this system is to minimize the amount of components.

Any input appreciated.

[Invigor]

I assume it's running dry because of the simple physics is the return is going to take the easiest least restricted route, which would be the first tank, then the second, then the third.

Easist way to remidy this would to put a ball valve for the return to each tank so you can control the flow to each individual tank. In your case you would probably leave the tank furthest away with the least restriction and restrict the closest tank so the water is forced to go to the furthest tank.

The overflows will only pull out what's being put in. so depending on the design of your overflows you might get noisy overflows if you're not giving enough flow. I found U tube overflows to be able to take any amount of water and not be noisy where as I had a cpr and unless I ran it to full capacity, it was sounding like i was living beside a white rappid river. :|

[Cap'n]

Originally Posted by Invigor

I assume it's running dry because of the simple physics is the return is going to take the easiest least restricted route, which would be the first tank, then the second, then the third.

Nothing is plumbed together right now, just theory. But you understand my problem correctly.

Originally Posted by Invigor

Easist way to remidy this would to put a ball valve for the return to each tank so you can control the flow to each individual tank. In your case you would probably leave the tank furthest away with the least restriction and restrict the closest tank so the water is forced to go to the furthest tank.

So you think there is no other way than to fiddle with the flows until I have the right combination?
There really isn't a "farthest" tank. Design is planned sump-reef-FOWLR-sump.

Originally Posted by Invigor

The overflows will only pull out what's being put in. so depending on the design of your overflows you might get noisy overflows if you're not giving enough flow. I found U tube overflows to be able to take any amount of water and not be noisy where as I had a cpr and unless I ran it to full capacity, it was sounding like i was living beside a white rappid river. :|

Three main concerns:
1) what happens when the power goes off?
2) what happens when the power comes back on?
3) how noisy is it going to be?

[Richer]

Personally, I wouldn't have overflows on all of the tanks, only on one of them. I would put the return line on one tank, then the overflow on the tank farthest away from the return tank, then just plumb all of the tanks together (either by U-tubes that extend far enough down the tanks to prevent siphon breaks, or by drilling and connecting them). That way, you'll essentially have one big tank. Additional flow can be done with powerheads of closed loops.

-Richer

[Invigor]

Originally Posted by cptclever

Three main concerns:
1) what happens when the power goes off?
2) what happens when the power comes back on?
3) how noisy is it going to be?

1) power goes off:
your tanks will drain however much the water level is over the overflow.
ie) I had a 48 gal tank running about 800gph, so the water lever was usually 1/2" over the lip of the overflow. When the power went out, that 1/2 of water went down so about 3 gallons EXTRA would flow into the sump. Not a big deal.
2) when the power comes back on, the water is pushed into the tank, it flows up and over the lip of the overflow, the overflow sends it back down to the sump given the syphon was not lost. if air got into the overflow and broke the syphon, I have a rio rvt hooked to the top of the airflow that sucks the air out and re-makes the syphon, then it drains normally. if there is air in the overflow it gets sucked out before there's enough water pumped into the tank to have it flow over the sides.
3) depends on how loud your pump is (i'm ungodly lucky and have the noisiest mag drive there is) and depending on the design of your overflow you might get zero noise from it, or a little trickle, or a loud splashing sucking noise.

my cpr running at full capacity was near silent.

[Cap'n]

Originally Posted by Richer

Personally, I wouldn't have overflows on all of the tanks, only on one of them. I would put the return line on one tank, then the overflow on the tank farthest away from the return tank, then just plumb all of the tanks together (either by U-tubes that extend far enough down the tanks to prevent siphon breaks, or by drilling and connecting them). That way, you'll essentially have one big tank. Additional flow can be done with powerheads of closed loops.

-Richer

I originally had planned on using only one overflow, but the more I thought about it the more it seemed necessary to have one on each tank. What if, for example, one powerhead or return pump fails. Then one of the tanks without an overflow could possibly flood. I'm just trying to cover all my bases.

Tanks are already set up and running, drilling is not an option. If I had U-tubes connecting the side-by-side tanks and the power went out wouldn't the siphon in the tubes continue and flood either one of the tanks? or the sump because of the gravity overflow?

[Richer]

The water in your tanks would flow from one tank to the other until everything levels out. So if all of your tanks are level then no one tank should flood... unless all three tanks flood. So if the return pump should fail, then the water level in all of your tanks will continue to lower (and fill the sump) until the siphon to your sump is broken. You just need to ensure that the sump is large enough to accomodate the extra water volume if the power should go out. Basically, as long as all of your tanks are level, it will act like one big tank. The biggest potential problem I see is having one of your U-tubes clogging. If that happens, then you can have a flood, since water cannot flow to the next tank easily. Multiple U-tubes and screens should reduce that risk.

-Richer

[Cap'n]

Originally Posted by Richer

The water in your tanks would flow from one tank to the other until everything levels out.

Right! Of course!

OK, I'm liking this idea. But how do I get the siphon started once I get the U-tubes installed?

[Cap'n]

Got it. Cap em and quickly submerge.

All right, doing some more research.

Thanks Richer, great way to make both tanks perform as one. That was causing me some problems in design, this simplifies it considerably.

[StirCrazy]

OK my theory on the whole thing, forget trying to link them in series and put them in parallel. get one big pump and have it go to 3 outputs (one for each tank with a ball valve on each to tune the flow. then have each tank return to the common sump. this is what I have for my 25 gal except I use a separate pump in the sump for it.

Steve