Adjusting Settings

[KOBrien12]

This summer we added a VSF pump, SWG, and Intelli pH. Another member was helpful with advice on getting everything up and running and suggested I run the VSF pump at the slowest possible speed (RPM) that the Salt Cell (ic40) requires to turn on (I'm at 1765 RPMs, 20 GPM) for 15 hours @ 100% to create about 3.5ppm of FC a day. It doesn't turn the all the water (30k gallons) but a member of TFP was really helpful in explaining that it's more so about generating chlorine than turning water.

Water Test Results/Help Needed

1. Chlorine: I addressed the CYA level and over two weeks it went from 40 -> 70 and Free Chlorine level went from 0.2 to 9.4 We've also been using a solar cover and that's probably keeping chlorine levels in. So, so I reduce the % of chlorine my IC40 is generating and keep running it at 15 hours or do keep the ic40 at 100% but run the pump for less than 15 hours a day?
*My pool guy seems to believe if you run it at a higher RPM and run for less hours it'll generate more chlorine but my understanding from TFP members is that regardless of RPMs the ic40 will produce the same amount of chlorine (it's either on or off for the amount of time the pump is on regardless of pump speed). Can you also clarify this?

2. pH: pH was 7.4 two weeks ago and now it's at 9.0. This might be because I reduced the Intelli pH from 50% to 30%. Should I change the settings to 40% to see if that brings it back down? I have the pool calculator which says how much acid to add to bring it to proper levels however since I have the Intelli pH it's a continuous drip so I want to figure out the right setting to keep it at. If I address the pump running time based on the above I'd imagine that will impact, too, the % I set the Intelli pH at. I don't want to increase it too high as that might drop the pH back down below where it needs to be, I want to drop it from 9 to appropriate levels and also maintain it.

Thanks for insights and advice! Grateful to you all!!

-Kyle

 

[mknauss]

Your solar cover is shielding the UV from the chlorine. Your 'pool guy' does not understand how a SWCG works. So either reduce your % generation or reduce hours. Your choice. Both will achieve the same result.

I would not treat your pool as if it has a pH of 9. I do not believe that is even chemically possible unless you added soda ash or borax to raise the pH. It would be wise to lower your pH using acid based on Poolmath with a starting pH of 8 and target 7.6. Add and circulate for 30 minutes and test pH again. Keep doing so until your pH is in the 7's. The adjust your dosing device to maintain that.

 

[KOBrien12]

Thank you for confirming what I suspected....’pool guy’ is right, it’s frustrating when I feel I know and understand more about pools than the person who should be teaching me - much gratitude to you and TFP for the knowledge I’ve built this summer!

What would you do? Keep SWG at 100% and reduce pump run time to save energy costs? Or reduce SWG % and keep run time to extend life of the salt cell? Also, would you agree that you don’t have to turn the water in your pool and it’s really just about running the system to produce a certain amount of chlorine in a day? What’s your suggestion on target generation for a 30k pool?
Thanks again!

 

[mknauss]

The SWCG does not care if it is run at 100% for 1 hour or 10% for 10 hours, both create the same chlorine and neither will make the unit 'last longer'.
With your pool size, unless you have a reason to not consume electricity during certain times of the day (time of use rates), I would suggest you run 24 hours per day and generate chlorine constantly. Turnover is a myth, so that is not the consideration. But your 30 K pool with a 40K rated SWCG. To generate ~3 ppm FC per day, run the SWCG at 60% for 24 hours per day. If you do not want to run the pump 24 hours, set the SWCG at 100% and run for 15 hours per day. Test FC daily and adjust either the % or run time up or down depending on your data.