Hayward Sense and Dispense in Spa vs Pool Mode

[guymandude]

Should a Hayward Sense and Dispense system (AQL-CHEM) turn off the dispensing of acid automatically when the ProLogic goes into "spa mode"?

My S&D reads pH too high (vs a manual test) when in system is in spa mode (e.g., 8.5 instead of 7.5), but is accurate when in pool mode. This causes the S&D to inject acid into the spa when not necessary, and it will continue for a time when the system switches back to pool mode, and this causes an actual reduction in pH that is too much, and the water in both the spa and the pool ends up being too acidic. I am showing signs of my plaster getting eaten away and have even had a couple of leaks around nozzles in the pool where too much acid has eaten away around the edges.

 

[JoyfulNoise]

This same issue was reported in another post a few weeks ago by a different user. Same exact problem with the same exact system. I'm not sure what the resolution was but I know they were working with their PB and Hayward on a possible resolution through warranty.

In general, these automated dosing systems should be shut off during SPA mode. Spa's are significantly smaller volumes of water that can and should be treated after use not while people are in it. There's really no major downside to waiting until after exiting the spa but there is a lot of downside if people are in the spa and the acid dosing system goes crazy.