Background - I had no experience with pools until renting this house 2 1/2 years ago. The property manager said it was easy, basically just add Trichlor tablets (I quickly learned that wasn't true but didn't know until now just how MUCH more complicated it is). He did buy me a test kit which tests FC, TT, pH, Alkalinity) and I've been keeping those pretty well balanced. I did have a hard time keeping my pH in range. It always seemed to be going low/acidic which I suspect was possibly due to...
I never had heard/read about CYA until I bought a box of shock from Costco which included some test strips. The CYA was off the chart high. Took a sample to pool store and their water tester said it was 197 ppm. Phosphates were also off the chart maxed out at 4000 ppb (water tester could not measure more than 4000). Long story short I did a lot of reading and knew I had to drain the pool. Not a good time considering the water situation out west but it had to be done.
I also never read about pools popping/lifting until now either but we live in a very dry area and are currently in a drought. The property manager agreed to let me drain it but he wanted to only drain it to expose the shallow end (which is a subjective area) to leave weight in the pool. It's a 22,000 gallon plaster in-ground. I REALLY wanted to get the CYA down below 50 ppm and ended up draining it more than he probably wanted me to (I'm guessing only 2500-3500 gal remained). Then I added about 2500 gal and then drained 2500 gal out again (I calculated both the fill rates and sump drain rate) before doing the complete fill.
The test strips now seem to show CYA is below 50 ppm but it's pretty subjective and will be going back to the pool store for another test. I know some people think the store tests are not very accurate. This store/chain (Leslie Pools) does calibrate their equipment but I'm open to recommendations on good CYA test kits although I'm thinking I don't have to add any more trichlor tablets if the CYA is in the 30-50 ppm range.
Also note I was starting to get black algae dots before draining. Not really bad. They were mostly less than 1/16" inch in diameter and not even visible unless you went down to the bottom with a mask/snorkel. While/after filling I added an initial dose of HTH Super Algae Guard and accidentally ended up adding almost 2x recommended initial dose (as opposed to maintenance dose). I know I know - many say don't use it, chlorine will take care of it, but I bought it before reading all of this so I figured it could only help. The pool now (just finished filling yesterday) has a green tinge to it which I'm hoping is just the algaecide.
After filling, alkalinity was 100 ppm, pH was 8.2 but a quart of muriatic brought it right down to 7.5. FC was of course non-existent.
I used a calculator that said I should add about 150 oz of 8.25% bleach to get from 0 to 5 ppm so in the late afternoon (I didn't want to wait until nightfall) I added about 160 oz and it only seemed to go up to about 2-3 ppm (I know I need to get a better test kit) but this morning it was already down close to 0 ppm.
Questions:
- What could have been using up the chlorine? The black algae?
- Walmart no longer sells bleach by the gallon. I bought the Great Value brand. It's 81 oz and advertised as "More Concentrated" 81 oz supposedly equivalent to 121 oz of their previous less concentrated bottles. I had thought that bleach normally was 6%. If that's the case then the math says the concentrated one should now be almost 9%. I'm skeptical. There was some Chlorox there that was only 4.5%. Walmart does not seem to list anywhere the new Great Value concentration. I just found a 2015 MSDS on their old bleach that only said it was 1-3% sodium hypo by weight and that it's actual value was a trade secret. Ugh. Does anyone have experience using this new "concentrated" stuff? Maybe it's just best to spend the $6/gallon at the pool store?
- Is there any point to shocking the pool right now (I'm guessing there is because of the algae) and what FC level should I be shooting for? What I have right now is 1 lb bags of HTH Calcium Hypo.
- Is there any difference between adding x bags of powdered shock and adding x bottles of bleach (other than one being calcium hypo and the other is sodium hypo)?
- I know it's best to add chlorine/shock at night but assuming I already have 30-50 ppm CYA in the pool so shouldn't that provide some "protection" against the sun if I add the bleach during the day? Even if I add it at night it's going to be exposed to sun the next day. The pool has full sunlight all day long.
- Does a solar cover provide any protection to the chlorine levels from the sun?
Aside: I read some threads today and see that I probably need to read about FAS-DPD test, BBB method and SLAM. Haven't done that yet so I know nothing and open to opinions on what I should be concentrating on.
I thought I had a decent handle on this stuff after reading so much about CYA but I read some more threads this morning and realize I still have a lot to learn. Thanks in advance for your expertise!
I never had heard/read about CYA until I bought a box of shock from Costco which included some test strips. The CYA was off the chart high. Took a sample to pool store and their water tester said it was 197 ppm. Phosphates were also off the chart maxed out at 4000 ppb (water tester could not measure more than 4000). Long story short I did a lot of reading and knew I had to drain the pool. Not a good time considering the water situation out west but it had to be done.
I also never read about pools popping/lifting until now either but we live in a very dry area and are currently in a drought. The property manager agreed to let me drain it but he wanted to only drain it to expose the shallow end (which is a subjective area) to leave weight in the pool. It's a 22,000 gallon plaster in-ground. I REALLY wanted to get the CYA down below 50 ppm and ended up draining it more than he probably wanted me to (I'm guessing only 2500-3500 gal remained). Then I added about 2500 gal and then drained 2500 gal out again (I calculated both the fill rates and sump drain rate) before doing the complete fill.
The test strips now seem to show CYA is below 50 ppm but it's pretty subjective and will be going back to the pool store for another test. I know some people think the store tests are not very accurate. This store/chain (Leslie Pools) does calibrate their equipment but I'm open to recommendations on good CYA test kits although I'm thinking I don't have to add any more trichlor tablets if the CYA is in the 30-50 ppm range.
Also note I was starting to get black algae dots before draining. Not really bad. They were mostly less than 1/16" inch in diameter and not even visible unless you went down to the bottom with a mask/snorkel. While/after filling I added an initial dose of HTH Super Algae Guard and accidentally ended up adding almost 2x recommended initial dose (as opposed to maintenance dose). I know I know - many say don't use it, chlorine will take care of it, but I bought it before reading all of this so I figured it could only help. The pool now (just finished filling yesterday) has a green tinge to it which I'm hoping is just the algaecide.
After filling, alkalinity was 100 ppm, pH was 8.2 but a quart of muriatic brought it right down to 7.5. FC was of course non-existent.
I used a calculator that said I should add about 150 oz of 8.25% bleach to get from 0 to 5 ppm so in the late afternoon (I didn't want to wait until nightfall) I added about 160 oz and it only seemed to go up to about 2-3 ppm (I know I need to get a better test kit) but this morning it was already down close to 0 ppm.
Questions:
- What could have been using up the chlorine? The black algae?
- Walmart no longer sells bleach by the gallon. I bought the Great Value brand. It's 81 oz and advertised as "More Concentrated" 81 oz supposedly equivalent to 121 oz of their previous less concentrated bottles. I had thought that bleach normally was 6%. If that's the case then the math says the concentrated one should now be almost 9%. I'm skeptical. There was some Chlorox there that was only 4.5%. Walmart does not seem to list anywhere the new Great Value concentration. I just found a 2015 MSDS on their old bleach that only said it was 1-3% sodium hypo by weight and that it's actual value was a trade secret. Ugh. Does anyone have experience using this new "concentrated" stuff? Maybe it's just best to spend the $6/gallon at the pool store?
- Is there any point to shocking the pool right now (I'm guessing there is because of the algae) and what FC level should I be shooting for? What I have right now is 1 lb bags of HTH Calcium Hypo.
- Is there any difference between adding x bags of powdered shock and adding x bottles of bleach (other than one being calcium hypo and the other is sodium hypo)?
- I know it's best to add chlorine/shock at night but assuming I already have 30-50 ppm CYA in the pool so shouldn't that provide some "protection" against the sun if I add the bleach during the day? Even if I add it at night it's going to be exposed to sun the next day. The pool has full sunlight all day long.
- Does a solar cover provide any protection to the chlorine levels from the sun?
Aside: I read some threads today and see that I probably need to read about FAS-DPD test, BBB method and SLAM. Haven't done that yet so I know nothing and open to opinions on what I should be concentrating on.
I thought I had a decent handle on this stuff after reading so much about CYA but I read some more threads this morning and realize I still have a lot to learn. Thanks in advance for your expertise!
Mine kept showing 35 so I added more and more and once I got the test kit it was 160!