Infinity pool catch basin overflowing

[Brad4]

Hi, I am new here (awesome place!). I bought my house about a year ago and had to learn everything about this pool with no help. The pool builder has not helped with my current problem. See signature for my pool details.

Problem: My pool is an infinity with spa all running on a single pump. Drains from the catch basin (trough), pool, and spa all go to the pump. If I have 2-3 people in the pool relaxing, I have no problems. However, if we start playing too much or get more than 2-3 in the pool, then the catch basin overflows. My current solution is to turn off the drain to the pool when we swim. This increases both waterfalls and allows more people to play before overflowing, but it is still not enough for say 4-5 people to play. Is it safe on my pipes to do this? Possible solutions: I have been told to install a 3HP pentair variable speed pump and crank to max when swimming (I know a varibable speed would decrease my electricity cost). My problem with this is that I read that my filter has a max 100 gpm flow and my 2 inch pipes have a max 73 gpm flow. I called the pentair company and was told that the 3 HP could definitely go much higher with my set-up (I did some basic calculations to figure my dynamic total head). I have read that maybe a surge tank maybe an option, but I'm not sure how this would work. I can not afford to do any re-building of the catch basin. Any help would be greatly appreciated. Thank you! See pics attached.View attachment 68269

Pool: 21,300 gallons. IG. Gunite. Outdoor. Full sun. Infinity. Attached spa. Catch basin size: 623 gal.
Filter: Sand (Pentair Triton II TR-100). Pump: 1 single speed pentair 2HP. Date of install: 2014. SWG: Hayward Aquarite T-15.
Test kit: Taylor K-2006 (for salt it is Taylor K-1766). Pipe size: 2 inches.

I attached the above because my signature is not showing up.

 

[mas985]

Is it safe on my pipes to do this?

Yes.

My problem with this is that I read that my filter has a max 100 gpm flow and my 2 inch pipes have a max 73 gpm flow.

Those are not actual limits but recommendations. The water will flow faster than that given the correct conditions. However, it is not recommended to do so.

You want to have the only suction port on the basin so it drains as quickly as possible. The pipe from that basin should have designed properly and be large enough to handle the flow. Do you know what size that is? Is there more than one pipe from the basin?

I did some basic calculations to figure my dynamic total head

Head calculations are never basic. How did you do it?

 

[Brad4]

@ mas985: My basin has 2 drains in it, but at the pump only 1 basin drain comes up from the ground and it is 3 inches. All other piping I can see is 2 inches. You have any idea how I can fix my problem? Thanks.

Regarding TDH: I used a formula I found on the internet for an estimate using filter pressure after a backwash. I did this awhile back and can not find the formula I used. I have no way of knowing how much pipe is underground as I can not get the builder to cooperate with me.

 

[mas985]

The only practical solution is to only draw from the basin. Does that not work?

 

[Brad4]

Okay, so, what I do now is turn off the valve for the pool drains. The attached spa drains do not have any on / off valves I can turn. This helps a lot, but does not allow enough drainage for say more than 4-5 people.

 

[mas985]

The spa drains should definitely have a valve. Can you not isolate the spa from the pool so the water both comes from the spa and also returns to the spa and visa versa?

Can you post a picture on the pad equipment and plumbing?

 

[Hayward Pool]

From listening to everyone I am suspect that the size of overflow basin may not have been built big enough. In helping builders with building infinity pools I find this to be the biggest problem. By knowing the square footage of the pool surface, length of weir along with the depth of the weir at the overflow I might be able to help.

 

[Brad4]

Thanks everyone. Ok, so I measured the length (curve) of the weir at 193 inches, the depth on the overflow side (near grass) at 30 inches, and measured estimate of the surface area of the pool (not with the spa) to be 800 square feet.

There is a valve to the spa, but it is on an automatic actuator. There are 2 of these (1 on the drain side and 1 on the fill side). My remote has a button to turn on spa mode. This turns both actuators so that only water drains from and fills into the spa.

Here are pics of my pad. Thank you in advance.

 

[mas985]

What is the width of the catch basin?

Also, without anyone in the pool and the pump running, what is the depth of water in the catch basin?

How do you set the water level in the pool?

When the water does splash out of the pool, does it over shoot the basin or fall in the basin and then overflow into the yard?

 

[Swamp Denizen]

I would like to find an industry expert to analyze my catch basin size and give me some thoughts on whether to sue my PB....The situation is that I have a 42 foot infinity edge on about a 15,000 gallon lap pool. The catch basin holds about 500 gallons and floods easily. I can provide more info if anyone is out there reading this and has thoughts....Thanks!

 

[JamesW]

Please begin your own thread so that we don't hijack this one.