Last spring I built a great pool and have enjoyed it everyday since new. I have not necessarily struggled to maintain the pool, but often times was somewhat flummoxed. If I knew what I knew now, things would have been easier. So here are the most valuable things I have learned in the last year of maintaining my pool as an OCD new pool owner.
Here are the particulars of my pool: 11,500 gal Salt water, So California location, direct sunlight, plaster, Pentair IC40 SWG, variable speed pump, cartridge style filter.
1) Everything is interrelated and knowing these relationships is critical
2) PH is probably the most important number to get right, maybe more important than FCL because a High PH makes FCL much less effective: Not sure of the exact number but Chlorine is only around 1/2 as effective at a PH of 7.8 than at a PH of 7.4. Lately, I have been trying to target a PH of around 7.5, not letting it get above 7.6. It seems as my total alkalinity has come down from over 200 to around 95-100, my PH is getting more stable.
3) A high PH also the greatest contributor, along with the obvious Calcium, to a high CSI and calcium buildup.
4) Using an app that can calculate CSI, like Pool Math is critical to determine the likelihood of calcium buildup or plaster erosion.
5) The Sun Lowers FCL in the pool.
6) CYA protects FCL from loss due to the sun, but CYA also makes FCL less effective at doing it's job. 30-50 is what is suggested through most google searches, however TFP recommends 60-80 for a pool like mine. My pool is at around 75 right now.
7) Total Alkalinity matters because if it is too high you can't keep PH from creeping up all of the time. Some websites say that Total alkalinity doesn't matter, others have said it is one of the first items to get under control. Well I can say that when it is at 200 or more you can't keep the PH from rising to 7.8 or 8.0 within days. I should have taken a more aggressive stance with Muriatic Acid to get it down to less than 120. New plaster pools take a lot of acid in the first year. I was afraid to use acid and my PH was often 7.8 to 8.0. Only after about 8 months did I learn that if Muriatic acid takes PH down to 7.2 you would use Aeration to raise the PH and then use Muriatic acid again to get total Alkalinity under control. I have some very mild calcium deposits on the spillway from the hot tub into the pool from my CSI being to high. This was because I didn't know about CSI, had a faulty reading on my CH reading from my Color Q due to bad reagents, and put in to much CH, and my PH was always too high. A triple wammy. For some reason I was just afraid to use MA, because by itself the stuff just seems so **** caustic. Now when pour it into the deep end, I immediately mix it up with pool brush so that it mixes in quickly.
8) Don't believe the standary FCL levels that are promoted. Everything that I read outside of this forum said FCL should be between 1-4. This is simply too low. This website would suggest more like 6-7 for my higher CYA values. Through experience, algae bloom is possible once my FCL gets towards 5ppm or less.
9) The amount of FCL generated by my Pentair IC40 is a function of the Percentage setting, the amount of run time per day and the speed of my variable pump. There is nothing in the IC40 that senses how much FCL is in the pool and generates based upon current pool values. The unit is dumb, I thought that maybe it was smart and had some ability to sense the water. It doesn't.
10) Don't believe the Salt water PPM reading from the IC40, it is all over the place, lower temperature water generates lower PPM readings.
11) When the flow switch on the IC40 starts going bad, FCL levels then go all over the place. Either the unit is working or just stops. It can be replaced independently.
12) Running the pentair variable speed pump at lower settings for longer hours saves a lot on electricity as watts used and pump speed are not proportional. Cutting the pump speed in half lowers wattage to about 1/4.
13) Some tests are more accurate than others. FCL TCL (CC), PH and Total Alkalinity seemed pretty accurate with both my LaMotte Color Q kit and my Taylor 2600c kit. CH was wildly inaccurate with my color Q until I updated my reagent. LaMotte and Taylor agree on FCL, but LaMotte gets inaccurate above about 8-9 and can't read above 10. CYA is probably the measurement that is most susceptible to mis interpretation, however my LaMotte generally agreed with my Taylor.
14) Combined Chlorine is what actually smells, and higher FCL levels like 6 or 7 are not harsh on the eyes. It is the CC that is harsh and smells like Chlorine, so don't be afraid of higher FCL levels
15) It is much easier to clean the cartridge filters than I thought. I can clean them in only about 15 mins and about 10 more mins if I clean the SWG at the same time. So I clean the filter more often than the recommended every 90 days.
When I decided to maintain my pool on my own, I strove to get all of the numbers correct. The problem with maintaining pool chemistry is three fold:
1) We are given wrong number to strive for from generic websites.
2) Measurement tools can produce wrong numbers and
3) Numbers can't be viewed in isolation. Pool chemistry is a interrelated ecosystem.
Here are the particulars of my pool: 11,500 gal Salt water, So California location, direct sunlight, plaster, Pentair IC40 SWG, variable speed pump, cartridge style filter.
1) Everything is interrelated and knowing these relationships is critical
2) PH is probably the most important number to get right, maybe more important than FCL because a High PH makes FCL much less effective: Not sure of the exact number but Chlorine is only around 1/2 as effective at a PH of 7.8 than at a PH of 7.4. Lately, I have been trying to target a PH of around 7.5, not letting it get above 7.6. It seems as my total alkalinity has come down from over 200 to around 95-100, my PH is getting more stable.
3) A high PH also the greatest contributor, along with the obvious Calcium, to a high CSI and calcium buildup.
4) Using an app that can calculate CSI, like Pool Math is critical to determine the likelihood of calcium buildup or plaster erosion.
5) The Sun Lowers FCL in the pool.
6) CYA protects FCL from loss due to the sun, but CYA also makes FCL less effective at doing it's job. 30-50 is what is suggested through most google searches, however TFP recommends 60-80 for a pool like mine. My pool is at around 75 right now.
7) Total Alkalinity matters because if it is too high you can't keep PH from creeping up all of the time. Some websites say that Total alkalinity doesn't matter, others have said it is one of the first items to get under control. Well I can say that when it is at 200 or more you can't keep the PH from rising to 7.8 or 8.0 within days. I should have taken a more aggressive stance with Muriatic Acid to get it down to less than 120. New plaster pools take a lot of acid in the first year. I was afraid to use acid and my PH was often 7.8 to 8.0. Only after about 8 months did I learn that if Muriatic acid takes PH down to 7.2 you would use Aeration to raise the PH and then use Muriatic acid again to get total Alkalinity under control. I have some very mild calcium deposits on the spillway from the hot tub into the pool from my CSI being to high. This was because I didn't know about CSI, had a faulty reading on my CH reading from my Color Q due to bad reagents, and put in to much CH, and my PH was always too high. A triple wammy. For some reason I was just afraid to use MA, because by itself the stuff just seems so **** caustic. Now when pour it into the deep end, I immediately mix it up with pool brush so that it mixes in quickly.
8) Don't believe the standary FCL levels that are promoted. Everything that I read outside of this forum said FCL should be between 1-4. This is simply too low. This website would suggest more like 6-7 for my higher CYA values. Through experience, algae bloom is possible once my FCL gets towards 5ppm or less.
9) The amount of FCL generated by my Pentair IC40 is a function of the Percentage setting, the amount of run time per day and the speed of my variable pump. There is nothing in the IC40 that senses how much FCL is in the pool and generates based upon current pool values. The unit is dumb, I thought that maybe it was smart and had some ability to sense the water. It doesn't.
10) Don't believe the Salt water PPM reading from the IC40, it is all over the place, lower temperature water generates lower PPM readings.
11) When the flow switch on the IC40 starts going bad, FCL levels then go all over the place. Either the unit is working or just stops. It can be replaced independently.
12) Running the pentair variable speed pump at lower settings for longer hours saves a lot on electricity as watts used and pump speed are not proportional. Cutting the pump speed in half lowers wattage to about 1/4.
13) Some tests are more accurate than others. FCL TCL (CC), PH and Total Alkalinity seemed pretty accurate with both my LaMotte Color Q kit and my Taylor 2600c kit. CH was wildly inaccurate with my color Q until I updated my reagent. LaMotte and Taylor agree on FCL, but LaMotte gets inaccurate above about 8-9 and can't read above 10. CYA is probably the measurement that is most susceptible to mis interpretation, however my LaMotte generally agreed with my Taylor.
14) Combined Chlorine is what actually smells, and higher FCL levels like 6 or 7 are not harsh on the eyes. It is the CC that is harsh and smells like Chlorine, so don't be afraid of higher FCL levels
15) It is much easier to clean the cartridge filters than I thought. I can clean them in only about 15 mins and about 10 more mins if I clean the SWG at the same time. So I clean the filter more often than the recommended every 90 days.
When I decided to maintain my pool on my own, I strove to get all of the numbers correct. The problem with maintaining pool chemistry is three fold:
1) We are given wrong number to strive for from generic websites.
2) Measurement tools can produce wrong numbers and
3) Numbers can't be viewed in isolation. Pool chemistry is a interrelated ecosystem.
Welcome to TFP! 
