Overnight FC rose from 41.5 to 44. Is this a pass?
- Thread starter DigitallyChallenged
- Start date
- May 3, 2007
- 16,950
- Pool Size
- 20000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
The PSI rise is proportional to the square of the RPM by the following formula.
PSI new = (PSI Old + 1.3) * (RPM New / RPM Old)^2 - 1.3
So doubling the RPM would change the PSI from 1 to about 7.9 PSI which is close to what you are seeing.
PSI new = (PSI Old + 1.3) * (RPM New / RPM Old)^2 - 1.3
So doubling the RPM would change the PSI from 1 to about 7.9 PSI which is close to what you are seeing.
Re: What is the upper limit of FC that is o.k. to swim in?
4 ppm FC is the maximum limit in the EPA drinking water standard so as a registered pesticide all chlorine products must caution against that being the maximum chlorine level. However, as noted by others in this thread, that limit does not take into account CYA in the water and the limit is based on drinking the water as opposed to swimming in it. Many counties and states have limits of 10 ppm for commercial/public pools as a result. The shock level of chlorine where the FC is around 40% of the CYA level has the same active chlorine (hypochlorous acid) level as 0.6 ppm FC with no CYA so is less than many indoor pools.BobW0295 said:
Turned off pump last night via Intelitouch and went to re-test this a.m. Pump was running but SWG off. I didn't change the schedule to none. 
FC 1.5ppm lower than last night but still above shock level at 30 ppm. Pool looks good. What now? What effect does running pump have on the test?
FC 1.5ppm lower than last night but still above shock level at 30 ppm. Pool looks good. What now? What effect does running pump have on the test?Update. Added borates and water was looking great. Clear and sparkling. It took until today w/o adding chlorine for FC to drop to 15. Water is not as clear and I think that there may be a slight algae film beginning. Did a full measurement:
FC 15
TA 110
CH 410
CYA is 75-80
pH appears to be 7.6
I measured my softened water and TA is 200! My well water is extremely hard and has iron. I added 2 cups of acid and I am attempting to get TA down. pH has been much more steady since I've lowered TA from 250. I used the pool calculator and added bleach to get to 30ppm.
Is the CH a big problem? If I add water to pool I will drive TA up. Can I leave the calcium level where we are now?
The weather has been sunny and in the high 80's to mid-90's. I am frustrated by the time it takes FC to drop. I had my shock level for at least 36 hours. I would have hoped that that would end any algae problem. Could the lack of water clarity be due to my chemical balance instead of algae? I plan on another overnight FC test Friday.
FC 15
TA 110
CH 410
CYA is 75-80
pH appears to be 7.6
I measured my softened water and TA is 200! My well water is extremely hard and has iron. I added 2 cups of acid and I am attempting to get TA down. pH has been much more steady since I've lowered TA from 250. I used the pool calculator and added bleach to get to 30ppm.
Is the CH a big problem? If I add water to pool I will drive TA up. Can I leave the calcium level where we are now?
The weather has been sunny and in the high 80's to mid-90's. I am frustrated by the time it takes FC to drop. I had my shock level for at least 36 hours. I would have hoped that that would end any algae problem. Could the lack of water clarity be due to my chemical balance instead of algae? I plan on another overnight FC test Friday.