How adjust pump speed for perfect trough level?

[Olle]

First a little background. Our infinity pool trough can sometimes overflow if a lot of people jump or make waves in the pool. You can mitigate this by running trough suction high. If large amounts of water had been splashing out of the main pool during swimming that difference gets magnified on the trough once they stop making waves. The trough therefore risks sucking dry once people stop swimming, especially if pump speed was set to high. (The trough has autofill, but needless to say it has no chance of keeping up with a pool pump pumping at the speed people are splashing in the pool. )

Question: Is there a way to let the trough water level signal the trough pump to smoothly vary the speed to keep the trough level within a certain range?
Pump speed to program:

INPUT -> RESULT
level within range -> normal pre set seasonal skimmer speed
water level high -> higher speed
water level low -> lower speed
overflow -> max speed
water level approaching empty -> stop pump

The trough pump is a Pentair intelliflo VSF. I have looked at Pentair's site and don't see anything about this.
Any ideas for a solution would be appreciated

 

[Jimrahbe]

Ollie,

I am surprised that you have a VS pump for your trough and also would have thought there would be afloat that turns the pump on and off??

Let's ask someone that knows... Calling @bdavis466

Thanks,

Jim R.

 

[Brett S]

It sounds somewhat counter intuitive, but you might want to lower the trough pump speed and then remove some water from the trough.

The trough should really be self regulating. When no one is in the pool and the water is still then only as much water as is pumped out of the trough will flow back into the trough.

If a bunch of water is splashed over the edge then the water level in the pool will go down a bit and the water level in the trough will rise. At this point little, if any, water will be flowing over the edge because the pool water level has dropped. The pump will continue to run and lower the water level in the trough and raise the water level in the pool until things get back in equilibrium.

The speed of the trough pump will affect the amount of water in the system and the water level in the pool. Assuming that you keep the water level in the trough the same, then if the pump runs at a high speed then it will be able to pump water into the pool faster, which results in a higher water level in the pool and more water in the system. It might not look like a significantly higher water level, but spread over the entire surface area of the pool it could be a good amount of water. If the pump is running at a lower speed then the water level in the pool will be slightly lower and there will be less water in the system overall.

So what I am suggesting is that you lower the pump speed. When you lower the pump speed you will notice that the water level in your trough gets higher. You will need to remove this extra water so there is enough room in the trough to handle the spillover from when people jump into the pool. You want to have your pump running at a low speed and the water level in your trough at a low level (although not so low that the pump is in danger of running dry)

Once this happens and people jump into the pool water will still splash over the edge, but it will be less water than you are used to, because the normal pool water level is lower than it would be if the pump was running at a high speed, so there is less water to go over the edge. Since less water is splashing over the edge then it shouldn’t overflow the trough and the pump can work on pumping out the excess water. Since the splash out has lowered the water level in the pool even further then little additional water will fall over the edge as the pump is working to lower the level in the trough.

 

[bdavis466]

This is the most common issue with infinity pools and it's caused by a trough that's too small.

There isn't really an easy fix since you'd either need to make the trough bigger or add a surge tank.

 

[Olle]

Thanks everyone for the advice. Yes I can definitely testify to owning a trough that is too small Will lower the trough level and install a shut off float. Any float models recommended?