a refresher course in sump designs

[dskirtech]

I would NEVER want to rely on a check valve to keep my sump from flooding. If you need 1 to prevent flooding, your setup is not right.
I had a 50g tank with a HOB overflow and a 10g sump....no check valve and never a flood.
I had a 75g tank with a HOB overflow and a 20g sump..no check valve and never a flood.
I currently have a 125 predrilled with a 55g sump...no check valve and never a flood.

Im sure there are 100 effective ways to plumb a setup, and Im certain some are more reliable than others. I would VERY interested to hear or see how your setup is designed where check valves are not a benefit. I do not post this to sound like a smart ass, I am genuinly interested to see how you have yours set up. since I will be doing some re-plumbing this weekend, it may pay off to change a couple things if it will make it better.

Thanks!

Dane

 

[project5k]

setting it up so that you dont need a checkvalve isnt that hard, drill the holes in the return for the syphon break, and then set the overflow higher than you have it now.

I have noticed that you have said on more than one occasion that you have yours set deeper to increase the flow. This worries me that your trying to get more out of a unit that may be too small for the flow you need, and perhaps you should consider a larger volume overflow so that you can set it to a higher position in the DT and thus eliminate the need to set it deep. (this will also greatly reduce the amount of water that continues to run out of the DT and down to the sump after the return pump stops.)

something else that you may want to consider is the design of your sump, if you have the "normal" operating depth set high, then your chances of overflow are higher, but like on mine, the water during normal operation is only half the depth of the tank, so when the power goes out, i still have 5 gallons of space in the sump. well theres not 5 gallons total in the return hose and the overflow box, maybe more like 1 gallon, so when the return pump stops, i dont overflow, even with the return line emplying back into the sump.

 

[dskirtech]

All GREAT points.

1. You are correct. My overflow is a piece of junk. I have purchased a HUGE Eshopps that i will be installing this weekend and hopefully will be able to raise my water level. I think you are correct in that I have a crappy one currently

2. I have a 30 Tall that is running @ about 2/3 level. I have it slightly higher because I wanted a deeeep sandbed in my fuge and my LR submerged. I will play with the overflow first and then re-visit.

 

[ccCapt]

Project got it covered.
You should have a hole drilled just below the water line on your return so the siphon will break when the water level drops. When the pump is off, the overflow should only drain a few gals into the sump and that should drop the water level low enough to break the siphon on the return where the hole is drilled.

I have purchased a HUGE Eshopps that i will be installing this weekend and hopefully will be able to raise my water level.

Make sure it's not too big, which is as bad as being too small. If it's rated for a much higher capacity than your pump (say a 1200gph overflow with a 400 gph pump), you can get air bubbles accumulating in the u-tube because the flow isn't fast enough to push them thru. You always want to match your overflow and pump. A 800gph overflow is a good match for a 600gph pump.

 

[dskirtech]

Make sure it's not too big, which is as bad as being too small. If it's rated for a much higher capacity than your pump (say a 1200gph overflow with a 400 gph pump), you can get air bubbles accumulating in the u-tube because the flow isn't fast enough to push them thru. You always want to match your overflow and pump. A 800gph overflow is a good match for a 600gph pump.[/QUOTE]


Thanks CC...

My *NEW* Overflow is MAX 1200 and my pump is a Mag 950. Currently Im having to use the Ball valve to cut back the pump because it cant keep up (overflow set as low as it will go).

Im planning on installing the Eshopps this weekend and I will drill the holes you reccomend, and then use the Overflow depth adjustment to regulate flow with the return wide open.

Sound logical?

 

[project5k]

now it sounds like you got it figured, and are headed down the right path... except you dont really use the overflow depth to controll the flow, more like you use it to set the running depth of water in the DT. start off with it as low as it will go, and run the pump wide open. then slowly raise the inside box up to raise the height of the water in the DT, when its where you want it, and everything is still running, you've got it set. thats how i did mine, and i havent had a loss of syphon or an overflow since i got it set.

just watch the overflow for the first couple hours and see if any air bubbles get trapped at the highest point in the u bend part(the part that actually goes over the top rim of the tank)

you might even take some airline tube and put it down in the tank side and blow gently and make a couple bigger bubbles(not too big so as to kill the syphon) but i think you know what i mean, and watch the bubbles in the u bend part, if they just go zooming through, then your good, if they get to the high point and stop, then you need more flow(more pump not deeper set depth)

i dont have enough overflow, or enough pump right now to get the tank and sump flow that i really need, but i'm thinking i'll get a second overflow just like the one i have now, and double up.. my overflow is rated for 300gph, and my pump with that head height is at like 290, so i'm just about perfectly matched. when i do the bubble test, the bubbles go screaming through there like a kid in a tube ride at a water park.

 

[dskirtech]

now it sounds like you got it figured, and are headed down the right path...
just watch the overflow for the first couple hours and see if any air bubbles get trapped at the highest point in the u bend part(the part that actually goes over the top rim of the tank)

you might even take some airline tube and put it down in the tank side and blow gently and make a couple bigger bubbles(not too big so as to kill the syphon) but i think you know what i mean, and watch the bubbles in the u bend part, if they just go zooming through, then your good, if they get to the high point and stop, then you need more flow(more pump not deeper set depth)

Actually already have this contingency planned for... I am going to use the Lift Pump and some extra tubing I have to keep that air pocket gone. ;-)

 

[project5k]

can you explain that a little more for me, i'm not getting a clear picture in my head..

if your talking about doing what i think your talking about, then i would like to caution you to not make the mistake i did, i used a suction source to pull the air bubbles out of the top of the u bend on mine, and thats all fine and well, but what i soon figured out was that when everything was up and running it was fine, but then when the power went out, and would come back on, the suction source would start up faster than the lift pump could get the water from the sump up to the tank and what ended up happening was it sucked the water outta the retention trap on the outside of the overflow, thus causing a much bigger air bubble and not allowing the water to flow by breaking the syphon...

if you look at the pictures in my showcase thread, and you find the one of my overflow, you'll see the blue tube that i put in there that went to the suction source to pull out the air bubbles. what i finally figured out was that the pump i was using was just too small and that was why i was having issues, when i went to a pump that was big enough to get the air bubles to just flow on through, rather than collect at the top, then i stopped haveing any problems whatsoever.