Spa spillway: always on = high acid demand?

[speifer]

Hi! Is it normal that the spa spillway to the pool cannot be turned off when the pool pump is on?

My pool's acid demand is very high even though the salt water chlorinator only runs at about 40% in the summer. I suspect the aeration from the spill-back (from the spa to pool) is the reason for the high acid demand.

It seems like it would make sense to have a valve allowing for the spillway to be turned off. Mine only has the check valve, but no way to turn it off. Is this normal?

Thanks,
Steve

 

[mas985]

First, welcome to the forum!

Yes, the extra aeration can cause PH to rise. Lower TA can help some.

As for turning it off, it depends on your setup. If the valves are automated, then there is usually a way to do turn off the spillover with the controller. If you don't have a controller, then it might be possible with other valves but it doesn't sound like the PB set it up that way. It might be easier to take a picture of your pad equipment rather than trying to describe it.

 

[257WbyMag]

You may be able to install a valve that allows you to isolate the spillover. Along with what mas985 said, a picture would help us see what is what.

 

[Richard320]

Yes.

My spa has a separate valve, so I reduced the flow to it and the pH rise slowed down considerably. And after a huge amount of rainwater dilution pushed the TA down to about 50, pH stayed fairly stable.

Your pool will have its own personality, so you'll have to find your own "sweet spot" for TA.

 

[speifer]

Thanks for the feedback! I added a picture for clarification (sorry its blurry, its all I have at the moment). You can see on the left side of the picture a check valve for the spa spillover. Next to that, there is a hand valve. That hand valve can throttle the pool jets. When I close the hand valve, the pool jets shut off, and the flow over the spillway increases. When the hand valve is full open, water flows through the pool jets, but some water still goes to the spa and flows over the spillway.

Unfortunately, there isn't much room to add a valve to turn off the spillway completely. Is it normal not to have a valve for shutting it off? Any other suggestions? Thanks again!