As I understand, your salt cell should be sized for twice your pools capacity. I have T-9 for my 13,000 pool and finding that with days of blistering sun the cell produces just enough FC at 100% (roughly 8.0 FC/day). With your size pool you'd fall short on extreme days. Stick with T-15.
FC consumption and SWG
- Thread starter bobandsherry
- Start date
Re: Hayward T 15 versus T9
No way you should be needing 8ppm of FC daily. Suspect something in the pool or your CYA way too low.
Re: Hayward T 15 versus T9
Here's my details:
I did an OCLT a week ago. The change overnight was 1.0FC. Since then I've been running my SWG at 85% for 24 hours, if my math is right that's producing 7.3 FC/day.
Here's my current test results:
FC: 7.0
CC: 0.0 (5 drops and no color change)
pH: 7.6
TA: 80
CH: 340
CYA: 70 (raised from 50 about a week ago)
Salt: 3000
CSI: -0.13
A week ago my FC was 12.0. So again if my math is right, 12+(7*7.3)-7 = 56.1 consumed for 7 days, or 8.0 per day for the past week (lots of bright sun for most days).
Two days ago my FC was 7.0, so calculating 2 day loss: 7.2+(2*7.3)-7 = 14.6 consumed for 2 days, or 7.4 per day (has been cloudy for past day with light rain).
Going even further back in my results, in early July I was concerned with the level of FC burn per day. So I had raised my FC to 28 and held it to kill off anything that may be bad in the water. My test on 7/5 had my FC at 26.2. I dropped my SWG to 80%, then with FC level dropping I increased it to 85% a week later. For the 17 days then the FC consumption: 26.2 + (7*6.9) + (10*7.3) - 7 = 140.5 or 8.3/day. Initially my CYA was at 40, I had increased it to 70 about a week ago so the lower CYA for the first 10 days would account for the higher consumption.
Pool is in a screen enclosure. SWG is about 1 year old, amps and volts are well within reasonable levels (6.2 / 24.0), about the same under reverse polarity.
I'm doing another OCLT tonight to check it again.
Again, I'd appreciate it if you see anything that is obviously wrong my test results, calc of the FC daily consumption or my approach.
I thought so too, over the past year I've learned a lot from here, but perhaps there is something I'm overlooking.
Here's my details:
I did an OCLT a week ago. The change overnight was 1.0FC. Since then I've been running my SWG at 85% for 24 hours, if my math is right that's producing 7.3 FC/day.
Here's my current test results:
FC: 7.0
CC: 0.0 (5 drops and no color change)
pH: 7.6
TA: 80
CH: 340
CYA: 70 (raised from 50 about a week ago)
Salt: 3000
CSI: -0.13
A week ago my FC was 12.0. So again if my math is right, 12+(7*7.3)-7 = 56.1 consumed for 7 days, or 8.0 per day for the past week (lots of bright sun for most days).
Two days ago my FC was 7.0, so calculating 2 day loss: 7.2+(2*7.3)-7 = 14.6 consumed for 2 days, or 7.4 per day (has been cloudy for past day with light rain).
Going even further back in my results, in early July I was concerned with the level of FC burn per day. So I had raised my FC to 28 and held it to kill off anything that may be bad in the water. My test on 7/5 had my FC at 26.2. I dropped my SWG to 80%, then with FC level dropping I increased it to 85% a week later. For the 17 days then the FC consumption: 26.2 + (7*6.9) + (10*7.3) - 7 = 140.5 or 8.3/day. Initially my CYA was at 40, I had increased it to 70 about a week ago so the lower CYA for the first 10 days would account for the higher consumption.
Pool is in a screen enclosure. SWG is about 1 year old, amps and volts are well within reasonable levels (6.2 / 24.0), about the same under reverse polarity.
I'm doing another OCLT tonight to check it again.
Again, I'd appreciate it if you see anything that is obviously wrong my test results, calc of the FC daily consumption or my approach.
- May 3, 2014
- 58,521
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
I'm also in FL with similar sized pool but I have the t15, now with the storms lately my FC demand has been under 1. I have a southern exposure about 75-80% sun (no trees in my yard but a partial shade in the morning from my neighbors trees. I have cut down my run time to 3.5 hours at 20% and with all the cloudy stormy weather I'm turning off my SWG 1-2 days a week. I think my screen severely affects the suns potency, I never get a sunburn under the screen, and even on the sunniest days I don't think my FC demand ever exceeds 2.0. If my t15 ever dies (which at the rate of usage will be for something other than exceeding it's chlorine demand) I'd consider the t9 or even t3 for my next cell.
Well, OCLT test had a drop from 5.4 to 3.6 (SWG was off). Not sure how as my FC has been maintained well above target but looks like something ugly has managed to crawl back into the water. SLAM underway, last test FC had reached 28, so now just into a monitor and maintain until FC holds during next OCLT.