High PH SWG

[chem geek]

waste is correct. Since you now have an SWG, you should try lowering your TA to 80. Use Ben's Lowering Your Alkalinity procedure to get the TA to this lower level. Try that first and see how much of a pH rise you still have. I suspect it will be less and you will be adding a lot less acid as well. You should also target a higher pH, such as 7.7 instead of 7.5 which will also help (and will be better for chemical balance, unless you increase your CH instead, but you can do that later if this works).

Have you noticed any rise in the CH level over time? If so, then that could be calcium hydroxide from curing, but I didn't think that refinishing involved any new plastering.

The use of 30-50 ppm Borates would help reduce chlorine usage by cutting down the amount needed to kill algae, but with your electric cover you should be having your SWG set pretty low anyway since you shouldn't be losing much from sunlight. I'm a bit surprised that with a cover you still get a lot of outgassing of carbon dioxide since I would have figured it would get pretty saturated rather quickly under the cover. Anyway, try the lower TA first. Then we can see if moving to Borates is something you want to try after that.

Anyway, there's no need to have a high TA with an SWG so let us know what happens when you lower it. Since you keep good logs, we know you'll have a complete set of numbers.

The only other interesting thing is that you are measuring combined chlorine which is very unusual to see in a pool with an SWG. I would leave the cover open for one sunny day (cover it again for night) and see if that takes care of the CC (you may need to turn up your SWG for that day since it will be exposed to lots of sun). You could also shock the pool by adding liquid chlorine, but I'd try the full day of sun first to see if that does the trick.

Richard

[micon2]

Thanks Chem Geek! I will try lowering the TA to 80 and then monitor and post the results. The CA has been rising, so maybe the pool is still curing? I did turn the SWG way down as well, your right that with the cover it does reduce the chlorine usage, and also left the pool open during several days over the weekend. I appreciate your response and assistance.