Recently switched to salt system (Pentair IC60; 30,200 gal pool) after almost 20 yrs of standard chlorine process. Trying to get the pool dialed in and could use some help. Will search for a few answers first but no doubt will post looking for opinions. Will provide all the pool details at that time.
30,200 gallon. 40x20 8ft deep end, 3’ shallow end, vinyl liner just replaced
1.5 hp Hayward single speed pump
Hayward S200 Sand filter. Rated at 167LPM sand changed @ liner change. Otherwise every 3rd season.
Full sun exposure during pool season from about 11am to 5pm.
Full shade from about 6pm until 8am
Pentair IC60 (went oversize to increase cell life) installed 60 days ago.
Pump runs 16hrs a day. 10am to 5pm and 9pm to 5am during pool season - May to Sept.
IC60 set on 40% run time
Testing - I learned years ago that if I followed the pool stores testing and chemical regimen I’d spend several hundred $ per month on chemicals. At one point I had the TF100 kit but in recent years have managed it with the smaller K1001 and test sticks. I decided I’d start out letting the store test the water for couple of months since I’m new to the salt thing and then once I have feel for it, purchase the TF101 and do my own testing. I’ve also been testing concurrently using the T101 and test sticks just to compare to what the pool place reports. So far they are pretty close.
Salt cell. / pump run time - is my run time and cell % in the ball park? It seems to be but I’d like to some feedback. up until the week I went on vacation (last week in June) it was perfect. Chasing some green since. I’m thinking I let the ph get high while I was gone and have also noticed the pool light is full of green water. …which it was not before we left. Reading up on SLAM.…
Sand filter- I thought this sand filter flow capacity is JUST large enough and maybe even a bit low. Thoughts? Have always had to keep FC high during the heat of the summer (6-7) and brush it every 2-3 days to keep the green away.
PH level - the one thing I’m seeing, as expected, is the rise in the PH level each week with the salt system. It goes from 7.5 to 8.0 each week. Add 3-4# of ph dry acid / decreaser on Saturdays, rinse repeat the next week. Using the pool calculator and checking prices of 31% MA, Ive figured out (I think), I can add 36oz a week (18oz on Sunday, 18oz on Thursday’s to even it out) at about 60% less cost than using the dry acid / ph decreaser and keep the ph where it needs to be - 7.5 ish. Eliminating the Yo-Yo. It seems chasing the ph level is the main thing I’ve had to get dialed in. Does this sound about right?
Averages
FC 2-3
TC 1.9 - 2
CYA averages about 60
PH 7.5. - 8.0
I have a few other questions but wanted to start here as a baseline.
You are generating 2.1 ppm FC per day. That is on the very low side of normal at this time of year. Doubling that would be a wise start.
Please do not use dry acid with a SWCG. Your manual from Pentair specifically points out to not use that product as it will destroy your SWCG.
The SWCG does not appreciably effect the SWCG. You do not report your TA but likely you need that to come down by managing your pH.
If you have seen any algae, you need to do an Overnight Chlorine Loss Test.
Get your FC up to target level and use the SWCG to maintain that. See FC/CYA Levels
Without giving the most current values, your "averages" may or may not be indicative as to what needs to be done.
As mknauss noted, using the "averages", you are running on the low side of your ideal FC number. The TC (what is usually called "CC" here) is high, hence demonstrating the algae problem you are chasing. Read up here, and follow the process, for doing a SLAM to get your TC down to .5 or 0. Do the Overnight testing to verify that you've done the SLAM long enough to kill all the algae. THEN start monitoring to find the steady state settings for your SWCG to produce enough to keep it in the recommended range for your CYA levels. Between the two (SLAM and monitoring) it may take a week or longer to find the going forward balance point.
30,200 gallon. 40x20 8ft deep end, 3’ shallow end, vinyl liner just replaced
1.5 hp Hayward single speed pump
Hayward S200 Sand filter. Rated at 167LPM sand changed @ liner change. Otherwise every 3rd season.
Full sun exposure during pool season from about 11am to 5pm.
Full shade from about 6pm until 8am
Pentair IC60 (went oversize to increase cell life) installed 60 days ago.
Pump runs 16hrs a day. 10am to 5pm and 9pm to 5am during pool season - May to Sept.
IC60 set on 40% run time
Testing - I learned years ago that if I followed the pool stores testing and chemical regimen I’d spend several hundred $ per month on chemicals. At one point I had the TF100 kit but in recent years have managed it with the smaller K1001 and test sticks. I decided I’d start out letting the store test the water for couple of months since I’m new to the salt thing and then once I have feel for it, purchase the TF101 and do my own testing. I’ve also been testing concurrently using the T101 and test sticks just to compare to what the pool place reports. So far they are pretty close.
Salt cell. / pump run time - is my run time and cell % in the ball park? It seems to be but I’d like to some feedback. up until the week I went on vacation (last week in June) it was perfect. Chasing some green since. I’m thinking I let the ph get high while I was gone and have also noticed the pool light is full of green water. …which it was not before we left. Reading up on SLAM.…
Sand filter- I thought this sand filter flow capacity is JUST large enough and maybe even a bit low. Thoughts? Have always had to keep FC high during the heat of the summer (6-7) and brush it every 2-3 days to keep the green away.
PH level - the one thing I’m seeing, as expected, is the rise in the PH level each week with the salt system. It goes from 7.5 to 8.0 each week. Add 3-4# of ph dry acid / decreaser on Saturdays, rinse repeat the next week. Using the pool calculator and checking prices of 31% MA, Ive figured out (I think), I can add 36oz a week (18oz on Sunday, 18oz on Thursday’s to even it out) at about 60% less cost than using the dry acid / ph decreaser and keep the ph where it needs to be - 7.5 ish. Eliminating the Yo-Yo. It seems chasing the ph level is the main thing I’ve had to get dialed in. Does this sound about right?
Averages
FC 2-3
TC 1.9 - 2
CYA averages about 60
PH 7.5. - 8.0
I have a few other questions but wanted to start here as a baseline.
Your FC recommendation of 2-3 from the pool store (if that’s where it came from) is assuming there’s no (or very little) CYA in the water. Once your CYA gets over that you need more FC to stay sanitary. Use the CYA/FC chart mentioned above to manage your chlorine levels.
When I say dry acid I’m talking about the Bio Guard PH Decreaser . Comes in 8# bag of granules. Maybe I’m using the wrong term?
It sounds like, speaking very generally at this point, I’ll need to run the SWGC much higher than I had anticipated. Closer to 80-100%. Interesting since they and several other places I got quotes from wanted to sell me an IC40 which would not make enough chlorine. They all kind of scoffed at the 60. …but they are in the biz of selling chemicals. I get it.
Thoughts on sand filter size / flow rate being adequate?
Oh, and new SCWG users often read the instructions where it tells you to clean the cell with muriatic acid every X months. Don’t do that! If you manage the CSI like TFP recommends, you may never need to clean the cell of calcium scale. If you ever do need to, clean it with water or some other method before resorting to any acid. The acid eats away the precious metals on the plates and reduce the life of the cell.
We are different than pool stores, as we have clue about what we are doing..
We always recommend that a salt system be rated for at least 2 x the volume of your pool.. You have 30K pool so you need a 60K cell. This just points to the fact that all those people that wanted you to buy a 40K cell have no clue at all, about how saltwater pools work.
No matter what cell you have, you still have to replace the amount of chlorine your pool uses each day. Most pools use 2 to 4 ppm of FC per day.. More in the summer and less in the Fall and Spring.
Let's assume your pool uses 4 ppm of FC per day for now.. You will need to run your cell long enough and hard enough to produce 4 ppm of FC each day. That means you will need to run your pump for 16 hours a day, with the cell at about 80%..
If you don't want algae, you will need to keep your FC in the proper relationship to your CYA. See this chart. FC/CYA Levels
With a CYA of 60 you will need to keep your FC in your target range of 4 to 9 ppm. You should never get close to the minimum of of 3.
The reason you are seeing algae has nothing to do with your pH and everything to do with trying to run you pool with too little FC.
Once you have algae, keeping your FC at your target range will not kill it. It might keep it at bay, but it will still be there.
To Kill algae, you will need to do what we call a SLAM.. See this link..
You can't do a SLAM using your salt cell, you will need to use liquid Chlorine. And be able to accurately test your FC will above 10 ppm.
Are your electrical rates higher in the afternoon? If so and you are set on running it 16 hr/day then run it later at night until noon. NO need to run it during expensive rates.
I’ve always run it fairly close to 50/50 day/night just to keep it turned over more regularly. Not opposed to running it 16 hrs 8pm to noon if there’s no issue with having it sit stagnant for 8hrs straight during the hottest part of the day. Never thought much about the rates. I need to look into that
Notice “liquid chlorine” mentioned. Meaning bleach or is there another option you all use? I tried the BBB method one year yrs but have generally always used shock granules.
Notice “liquid chlorine” mentioned. Meaning bleach or is there another option you all use? I tried the BBB method one year yrs but have generally always used shock granules.
Meaning “plain” bleach which is labeled as shock or chlorinating liquid. Hardware stores and Walmart usually carry it cheaper than grocery stores. No Clorox “cloromax” technology, fabric softeners, perfumes, nothing.
Darin / BPerry -you both have size 60 SWCG’s and pool sizes in the neighborhood of mine. During the hot part of the summer, how many hours a day are you running your pumps and what % on the cell when everything is dialed in?
Darin / BPerry -you both have size 60 SWCG’s and pool sizes in the neighborhood of mine. During the hot part of the summer, how many hours a day are you running your pumps and what % on the cell when everything is dialed in?
I run my pump 24x7 at low speed when the pool is open. The chlorine is being generated maybe 8 hours per day somewhere around the 50% setting. It varies though so you can just set it and forget it. I’ll check once a week and adjust as needed.
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Only use muriatic acid.