White gritty scale

[Pappy]

The slower action in the deep end may be due to lower circulation and/or lower temperature. You might try hooking your vac head up and leaving it down in the deep end for an hour or 4 to stimulate circulation. See if you can tell a difference in the immediate area of the vac and other areas.

[Wapak]

Thank you Pappy, I will try placing the vac in the the deep end for a bit.