As you can see from the attached pics, I have a perimeter overflow pool. There is only one pump as the edge spill over is gravity fed back to a large collecting tank on the side of the house prior to being filtered and sent back to the pool. I would like more water to be pushed over the edge of the pool into the gutter however speeding up the pump really doesn't do anything. The only thought/question I had was how necessary is the main drain in this application? I was thinking of closing the valve to the main drain as the water going to the pump is currently a mixture between water from the collecting tank and the main drain in the bottom of the pool. I could close the valve to the main drain it should push all the water over the edge and possibly improve the effect of the pool, but my fear is that I really won't circulate all the water in the pool through the filter. Am I wrong? Any thoughts would be greatly appreciated.
Necessity of Main Drain
- Thread starter goldmaes
- Start date
- May 3, 2014
- 62,687
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Main drains are not necessary. Many new pools are built without them.
As you have one, you should keep a bit of water coming through it to keep it from becoming stagnant. Close the valve nearly all the way and see how that helps your other issue.
As you have one, you should keep a bit of water coming through it to keep it from becoming stagnant. Close the valve nearly all the way and see how that helps your other issue.
If you want to get real radical about it, why not re-plumb the main drain so it is a return. That should keep the water circulating. It would be like 1 very large in floor cleaning head. 
cfherrman
TFP Guide
What Marty said, I think your pump is undersized or something similar as changing things on the pressure side should matter and not the suction side. Go ahead and try full skimmer or full main drain and see if it changes anything.
Making a main drain for a return won't do anything, there's no pressure or 'jet'. Suchtion from a drain(or return) can help with heat distribution.
Making a main drain for a return won't do anything, there's no pressure or 'jet'. Suchtion from a drain(or return) can help with heat distribution.
I disagree, the amount water over the edge is directly proportional to the gpm's going into the pool. By using the main drain as a suction line you are now removing water from the pool which would equate to less water over the edge.
Of course it would make a difference. The op is worried about circulation. Introducing water to the bottom of the pool would help with circulation and heat distribution.
I am guessing all of this is negligible. I imagine since the edge is huge it would take a massive amount of water at huge gpm rate to push a bunch more water over the edge. Most likely a bigger pump would require larger piping then I have to compensate for it so it brings me right back to square 1.
How much more water over the edge are you looking for?
Have you tried it with the main drain fully shut off?
Can you tell if your returns are throttled in anyway or is it a variable speed pump set at a certain RPM?
Another option could be an additional pump with its own suction line down to the pit and use the main drain as the return for that pump.
If you are truly considering some of these options,
I believe those pools are engineered to pretty much work exactly how it is working now. So before you invest any money or time into it I would seek out some engineering advice from somebody who designs and installs those type of pools.
Have you tried it with the main drain fully shut off?
Can you tell if your returns are throttled in anyway or is it a variable speed pump set at a certain RPM?
Another option could be an additional pump with its own suction line down to the pit and use the main drain as the return for that pump.
If you are truly considering some of these options,
I believe those pools are engineered to pretty much work exactly how it is working now. So before you invest any money or time into it I would seek out some engineering advice from somebody who designs and installs those type of pools.
PoolNewb2020
Well-known member
I highly doubt that installing a bigger pump would have much of an effect OP is looking for. It would simply suck more water from the main drain.
The amount of water spilled over the edge is proportional to the amount being pumped into the pool. So I agree with the idea of re-plumbning the main drain into a return. More water pushed into the pool would equal more water spilled over the edge.
But these are all speculations, OP should post a pic of the equipment and plumbing. For all we know it may already be plumed so there there is no main drain.
The amount of water spilled over the edge is proportional to the amount being pumped into the pool. So I agree with the idea of re-plumbning the main drain into a return. More water pushed into the pool would equal more water spilled over the edge.
But these are all speculations, OP should post a pic of the equipment and plumbing. For all we know it may already be plumed so there there is no main drain.
- May 3, 2007
- 18,073
- Pool Size
- 20000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
Water will circulate just fine to all parts the pool. The velocity out of the returns is quite high and will easily mix the pool water without the MD. But have even tried this? Does the MD have it's own control valve?
How long is the edge?
cfherrman
TFP Guide
Ok some more water pumped into the pool is better......
So.....
Where are we getting this water from?
So.....
Where are we getting this water from?
It would come from the sump tank that the overflow water is collected in.
Throw a large sump pump temporarily into the catch basin and shoot the return water with a flex line to the pool. Easy way to see whata more water is gonna do with no investment or pipe work. If you show us a pic of the pad we can see what they set up. I have seen a similar setup with multiple pumps but they had water features too. Details please