Can I test CYA, pH, ALK, or CH when Chlorine is high? How often should I test FC/CC during SLAM? Thanks!
What Chemicals can I test during SLAM?
- Thread starter JJH1111
- Start date
You can't test the PH as you get false readings when your FC is higher than 10. Once you start a SLAM just test the FC. How often you test depends on how bad your water looks. Really bad and you will probably run through the FC quicker. I usually test every couple of hours and adjust accordingly depending on how fast my FC level is dropping.
- May 3, 2014
- 62,923
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Welcome to the forum!
During SLAM you only need to test FC each time. The CC is informative once in awhile. CYA should be tested if a significant water exchange has occurred (mulitple backwash or vac to waste).
Test the FC and add liquid chlorine as often as possible. Every couple hours to start, then 3-4 times per day with a minimum of twice per day.
Do not test pH if FC is above 10 ppm. The test results are invalid.
Be sure to use a 10 ml water sample, one scoop of powder, and each drop to clear is 0.5 ppm FC.
I suggest you read ABC's of Pool Water Chemistry and consider reviewing the entire Pool School eBook.
During SLAM you only need to test FC each time. The CC is informative once in awhile. CYA should be tested if a significant water exchange has occurred (mulitple backwash or vac to waste).
Test the FC and add liquid chlorine as often as possible. Every couple hours to start, then 3-4 times per day with a minimum of twice per day.
Do not test pH if FC is above 10 ppm. The test results are invalid.
Be sure to use a 10 ml water sample, one scoop of powder, and each drop to clear is 0.5 ppm FC.
I suggest you read ABC's of Pool Water Chemistry and consider reviewing the entire Pool School eBook.
Started the SLAM process 6 days ago. Pool is getting better, still cloudy blue. Hoping to be finished in 7 days, but probably not.
As per your suggestions, I need to test more frequently, every couple of hours, FC only. The test directions say 2 scoops of powder, but it seems that one is sufficient.
The Chlorine/CYA chart indicates a shock FC of 20.
The FC dropped to 14 a couple of days ago, so this may have set me back.
FC went from 26.0 to 23.5 overnight. CC = .5
Pool seems to be close, but we will see. Thanks for your help.
Daily chemistry:
As per your suggestions, I need to test more frequently, every couple of hours, FC only. The test directions say 2 scoops of powder, but it seems that one is sufficient.
The Chlorine/CYA chart indicates a shock FC of 20.
The FC dropped to 14 a couple of days ago, so this may have set me back.
FC went from 26.0 to 23.5 overnight. CC = .5
Pool seems to be close, but we will see. Thanks for your help.
Daily chemistry:
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- Mar 24, 2014
- 2,455
- Pool Size
- 32000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool SJ-55
Those 3" pucks are just going to raise your CYA (and therefore increasing your SLAM FC target). I am not sure why you are using it, that should generally be reserved for times you can not be near the pool (vacations, etc).
As Marty mentioned, don't bother testing pH with FC over 10. It'll read false high.
As Marty mentioned, don't bother testing pH with FC over 10. It'll read false high.
What would you suggest in lieu of the 3" pucks? We have had good luck with them in the past. The pool is open from May to October, and then closed for the winter. This winter was really bad, very warm temps in December, and crazy cold the end of January (-20s actual temps). Pool was black when opened. I should have drained and refilled it, but chose to clean and treat it.
I will test the CYA.
Thank you!
I will test the CYA.
Thank you!
Plain bleach or liquid pool shock (which is just bleach in a more concentrated form) is better. You get the chlorine without adding CYA. Your CYA level is high enough already. The 3" pucks add CYA with every puck.
- Mar 24, 2014
- 2,455
- Pool Size
- 32000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool SJ-55
Either liquid chlorine or a SWCG. Don't use Chlorox (uses an additive now that is no good for pools). Wal-Mart 10% from the pool section, or a hardware store that has fresh (check the date codes) and indoor stored chlorine.
Ok, thanks so much. I will turn the automatic chlorinator off, and monitor the CYA. Still like the idea of using the pucks when we are away from the pool for a time.
Pucks are great for extended time away from the pool just as long as you understand what they are going to do to your CYA level.
Just about done with the SLAM process. Can see the bottom at the 9’ deep end. Pretty clear, 7/10. Lost 2ppm overnight. Going to keep the chlorine above 20 for another day, then let drift down to 8.
Some SLAM Lessons learned:
Need to test the pool 3 times a day. Morning, noon and night. Once a day is not enough.
Process uses lots of FAS-DPD titrating reagent. There are 591 drops per ounce. I use the Taylor R-871 two ounce bottles. My shock chlorine is at at 20ppm = 30 tests per bottle. If SLAM lasts a week * 3 tests per day = 21 tests. I will order more reagent here at: R-0871 (2 oz) FAS/DPD reagent $14.00 for 2 oz is a better price than my pool store.
The Taylor directions say to use 2 scoops of the R-870 powder, but 1 scoop works at the 10ml mark.
We will stop using the 3” trichlor pucks, start using 12% liquid chlorine. Probably 1 gallon every other day. We will do all other tests once chlorine gets below 10. Curious to see what the other readings are.
Thanks everyone for the help.
Some SLAM Lessons learned:
Need to test the pool 3 times a day. Morning, noon and night. Once a day is not enough.
Process uses lots of FAS-DPD titrating reagent. There are 591 drops per ounce. I use the Taylor R-871 two ounce bottles. My shock chlorine is at at 20ppm = 30 tests per bottle. If SLAM lasts a week * 3 tests per day = 21 tests. I will order more reagent here at: R-0871 (2 oz) FAS/DPD reagent $14.00 for 2 oz is a better price than my pool store.
The Taylor directions say to use 2 scoops of the R-870 powder, but 1 scoop works at the 10ml mark.
We will stop using the 3” trichlor pucks, start using 12% liquid chlorine. Probably 1 gallon every other day. We will do all other tests once chlorine gets below 10. Curious to see what the other readings are.
Thanks everyone for the help.
For really high levels of FC you can do a 5ml water sample. Your accuracy will suffer but you will use less powder and reagent. Switch back to the larger sample size as you finish up. Your overnight chlorine loss test should be at the higher accuracy if you think you are done with the SLAM.
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