*help with against gravity dual-drain design please*

[monkiboy]

i'm learning the 50g isn't going to cut it as a frag tank as it's nearly full and i've just begun. so, i'm adding an 80 rimless just outside the fish room as a show frag tank.

 

on a separate project i'm making my skimmer external and placing it against the far wall in the fish room for easier maintenance and to create room in the sump. the skimmer is inside the fish room behind the wall that the new 80 frag tank will be outside the fish room.

 

problem is that the entry door to my fish room is between where the new frag tank will be and the sump to the existing system.

 

the easiest way to plumb the new frag tank in is to go straight down to the floor (30"), through the wall, across the fish room floor (12'), then up the sump exterior (18") and into the filter sock chamber of the sump. so i got roughly 10-12" delta between the drop and rise. the skimmer is inside the fish room and the drain at approximately at the same height as the tank that is on the outside of that wall. i'd like to be able to have both of these drains (the skimmer's and the new frag tank's) drain into one pipe across the fish room floor and back into the sump to keep things more clean looking and simple.

 

the skimmer will be fed approximately 500-1000gph. the frag tank can be fed whatever gph it needs to to make this work with the appropriate plumbing size but likely around 500gph as most the circulation will be from power heads for the SPS frag tank.

 

pipe along the floor and entry-way isn't a problem as that is easily concealed and protected.

 

so...anyone familiar with how i can successfully get this done? is it possible? what size pipe should i use for the drains and main drain back to the sump? what kind of flow would be necessary to combat the gravity? anything else i am missing or not thinking of?

 

here's a rough sketch i put together to put a visual to it. sorry, i don't have sketchup on this computer but i did try to keep things to accurate scale.

 

 

thanks for any help you can provide!

Edited February 27, 2014 by monkiboy

[AlanM]

what will keep detritus from settling in that 12' pipe on the floor?

[matt]

Quick initial thoughts etc...

 

Do the skimmer and tank drains keep the exit water under pressure or is the water entering the main drain vented? That may come into play.

 

If the water isn't under pressure, then you need a pipe big enough to handle the flow rates. If the water is still under pressure, then I would expect the size of the pipe wouldn't be so much of an issue. Either way, I would think about how you plan to deal with detritus settling in the main drain pipe and how you'll clean it. Perhaps you should think about putting the filter sock somwhere before the initial drop down to floor level.

 

I've got more epxerience with house plumbing than big tank plumbing...so hopefully others will chime in with better thoughts and ideas.

[AlanM]

Would it be easier to switch the position of the door and the skimmer/fragtank so you could have the frag tank and skimmer nearer to the sump? 

[monkiboy]

what will keep detritus from settling in that 12' pipe on the floor?

nothing really but i don't anticipate much detritus from the frag tank. the skimmer perhaps. i was thinking of using a couple true union ball valves to isolate and a few unions to be able to easily take it apart for cleaning every six months or so. and if i find it needs it more often then i can adjust accordingly.

 

Quick initial thoughts etc...

 

Do the skimmer and tank drains keep the exit water under pressure or is the water entering the main drain vented? That may come into play.

 

If the water isn't under pressure, then you need a pipe big enough to handle the flow rates. If the water is still under pressure, then I would expect the size of the pipe wouldn't be so much of an issue. Either way, I would think about how you plan to deal with detritus settling in the main drain pipe and how you'll clean it. Perhaps you should think about putting the filter sock somwhere before the initial drop down to floor level.

 

I've got more epxerience with house plumbing than big tank plumbing...so hopefully others will chime in with better thoughts and ideas.

the frag tank will have a standard durso drain so it will be vented. the skimmer will be external and would be under some pressure but is vented as well.

 

i think with diligent maintenance every few months, the detritus in the pipe wouldn't be an issue. would you agree?

 

what size pipe would cover my bases, would 1.5" suffice?

 

Would it be easier to switch the position of the door and the skimmer/fragtank so you could have the frag tank and skimmer nearer to the sump? 

i like the out of the box thinking! unfortunately, the entry as currently placed is the only place for the door.

[AlanM]

i like the out of the box thinking! unfortunately, the entry as currently placed is the only place for the door.

 

Cover the door and make a secret hatch under the frag tank that you would use to crawl into the fish room, haha.  Ooh, or dig out the outside of the foundation and put a new well door in from the outside.

 

Seriously, you're basically making a long P trap or toilet.  Seems like as long as you don't have the sump end under very much water, it should start up just fine, end up totally filled with water (so it pushes out all the air at the sump end) and anything you dump on the skimmer/frag end would just overflow into the sump and you're fine.  Be careful of the flow from the skimmer pushing back up the line and overflowing into the frag tank, though.  If there is more friction on the long run than there is height difference you might end up never getting any flow out of the frag tank because there will be enough back pressure from what the skimmer is adding.  Unless someone has some kind of fluid flow calculator you might just have to try it and see. 

 

1.5" pvc would be nice because you can get a sanitary Tee and use it for the connection to the main drain from your skimmer in your diagram above.  Get the flow going in the right direction as it enters that pipe.  If it goes fast enough I could see it fully emptying the frag tank pipe by treating it like a vent, basically, and pulling air into the line from the frag tank and pushing it across the floor into the sump.  Same thing could happen if the frag tank empties fast.  Could suck the water out of the skimmer and use it as a "vent".  Edit: So you're kind of making a vented toilet that the skimmer could "flush" by emptying the frag tank's overflow if you know what I mean.

 

FWIW, BeanAnimal's calculator lists 2650 gph as the full siphon flow rate with 12 inches of head.  So if the pipe was full of water across the floor, neglecting friction you could push 2650 gph through it just using 12 inches of gravity from your skimmer and frag tank.

Edited February 27, 2014 by AlanM

[DaveS]

 Be careful of the flow from the skimmer pushing back up the line and overflowing into the frag tank, though.

 

This is what I immediately saw.  Any obstruction on the drain to the sump and your frag tank will overflow from the skimmer.

[AlanM]

This is what I immediately saw.  Any obstruction on the drain to the sump and your frag tank will overflow from the skimmer.

two main drains? one for skimmer and one for frag tank, both going to sump? Seems simpler.

[monkiboy]

This is what I immediately saw.  Any obstruction on the drain to the sump and your frag tank will overflow from the skimmer.

 

two main drains? one for skimmer and one for frag tank, both going to sump? Seems simpler.

yeah, i think you gents are right. although i could always just use a check valve but those always tend to fail. two 1" drains should do the trick instead of fiddling with check valves i suppose.

[mbat]

Your drawling shows what appears to be a gravity fed skimmer, not being a smart ass here, how are you going to get flow on a non pressured system to flow through when the skimmer is hooked up? Skimmer supply and drain lines are the same pressure. The line will fill but not flow, its one linear line with gravity pushing down. I would think adding a pump before skimmer with a ball valve and unions would leave you with the best results and control. This way you can run whatever drain size you want to the sump independent of the skimmer.

[monkiboy]

thanks for the feedback. the skimmer and frag tank will be fed from available ports off of the return manifold connected to the return pumps in the sump. perhaps i should have added the inputs to the frag tank and skimmer in my crude sketch - sorry.

 

i do plan on feeding both with one main return and then splitting off one to the skimmer and the other to the tank. so it would be three pipes or tubing to keep a visual inspection easier facilitated (two main drains and one main return)

Edited February 27, 2014 by monkiboy

[Sharkey18]

A show frag tank???? Now your just showing off... 

[AlanM]

A show frag tank???? Now your just showing off... 

 

His water changes, salt-making, RO/DI making, and everything else are automated.  He wants to be able to nail the door to the fish room shut.  Or at least just go in there to get the skimmate locker and dump it out the back door. 8)

[monkiboy]

A show frag tank???? Now your just showing off... 

i'm running outta room here! "show" in the sense that i'll be very purpose built. it's a shallow and deep 80 rimless so i'm going to maximize the surface i have for frags galore in a very clean and sexy layout. no rock or sand, bare bottom, simple and maybe a special fish or five.

 

His water changes, salt-making, RO/DI making, and everything else are automated.  He wants to be able to nail the door to the fish room shut.  Or at least just go in there to get the skimmate locker and dump it out the back door. 8)

getting there and the superlocker has got a pump and float sensors. once full, it'll automatically dump to drain according to a advised schedule with alerts and cease of action during unusual behavior. no carrying poopy buckets. i think you and scott have both volunteered to help with my apex

Edited February 27, 2014 by monkiboy

[ctenophore]

It will work fine as drawn. My greenhouse tubs were plumbed exactly like this. The velocity of the water moving down creates a suction on the skimmer and frag tank drains. You won't get any detritus settling in that horizontal run. Tube worms maybe after a few years.

[AlanM]

It will work fine as drawn. My greenhouse tubs were plumbed exactly like this. The velocity of the water moving down creates a suction on the skimmer and frag tank drains. You won't get any detritus settling in that horizontal run. Tube worms maybe after a few years.

Should he put gate valves on the skimmer and frag tank outputs so he can limit how much water the suction pulls out? Otherwise I think there's a real possibility of "flushing" the overflow box on the frag tank or the body of the skimmer with the water level in the skimmer oscillating up and down.

[ctenophore]

Should he put gate valves on the skimmer and frag tank outputs so he can limit how much water the suction pulls out? Otherwise I think there's a real possibility of "flushing" the overflow box on the frag tank or the body of the skimmer with the water level in the skimmer oscillating up and down.

If there is a durso in the frag tank, it won't drain like that. If a siphon drain, then there should be a valve there anyway. The skimmer just needs a tee where the down turn has an ell, so air can get into the down leg and prevent a siphon (basically the same principle as a durso). Once the water falls to the 18" level where it would be equal to the sump if the power went out, it will build momentum and reach an equilibrium of air and water in the "flooded" section of the pipe.

[ctenophore]

Adding to this. If the end of the output pipe is submerged in the sump, a slow siphon will form in the "U" comprising the vertical 18" sections and the horizontal run. If the end is above water, that U will contain air as well and may not drain as easily since the air will add friction to the moving water, reducing the momentum. I noticed that my greenhouse overflows moved water better when the output was submerged.

[ctenophore]

Also. I used 3" drain pipe to move 5000gph. I think 1.5" should be enough here, but if 2" is possible (don't mind stepping over it) then that's preferable.

[zygote2k]

You could always plumb in one of those on demand sump pumps...

[davelin315]

Why not just use a decent sized pipe with an air vent at the sump and plumb it directly into the sump rather than rise above? This will leave it as a pure gravity fed line and since your sump water level should never rise to the level of your drains, no backflow, either, as there would be no siphon created in the event of pump power loss.

[zygote2k]

sounds like 80g frag tank is in the wrong room.

[monkiboy]

thanks for the replies guys.

 

dave, your idea is very simple and i like running the drain directly into the sump vs up and over as it makes the plumbing job look that much cleaner.

 

to make sure i understand correctly, please confirm this is what you mean...

 

so my running water level is about 10" in my sump. i would use a 1.5" or 2" pipe for the main drain (back to the idea of running only one pipe for both the frag tank drain and the skimmer drain) then have that go across the 12' span to the sump, then go up along the outside of the sump to about 12" and drill a bulkead for the drain exit into the sump above the 10" running water line. on the inside of the sump, i could use a tee with the upper open (vented) and the lower draining down into the sump below the water line to prevent excessive noise and splash or even into a filter sock. is that correct? i do like the idea of going straight into the sump and not up and over.

[dante411x]

Your setup sounds pretty intense. And awesome. I'm highly jealous

The only question I have is why not just have two return lines going to the sump? That way if something happens, you don't have to wonder where things are failing. And if you're doing some skimmer maintenance, no need to turn off the flow to the show frag tank. Seems that if you're going to have a return pipe going across the room, what's the difference with having two pipes going across?

[monkiboy]

Your setup sounds pretty intense. And awesome. I'm highly jealous

The only question I have is why not just have two return lines going to the sump? That way if something happens, you don't have to wonder where things are failing. And if you're doing some skimmer maintenance, no need to turn off the flow to the show frag tank. Seems that if you're going to have a return pipe going across the room, what's the difference with having two pipes going across?

thanks for the input, sir.  think you are confusing drain and return. there will be two pipes or tubing run from the return manifold from the sump. one for the skimmer and one for the frag tank. we have been discussing the use of one or two main drains from the skimmer and frag tank.