Quote Originally Posted by chem geek View Post
It is normal to not show any combined chlorine. If you did the test correctly, you started with your pool water sample (25 ml or 10 ml depending on the resolution you want), you added 2 scoops of powder (R-0870), the sample turned red/pink, you then added drops of titrant (R-0871) and counted them, then the sample turned colorless and the number of drops was multiplied by 0.2 if using the 25 ml sample or 0.5 if using the 10 ml sample to get Free Chlorine, then you added 5 drops of R-0003 and IF there is any Combined Chlorine the sample turns red/pink and you add more titrant (R-0871) until it turns colorless. It sounds like your Combined Chlorine (CC) was zero and that's normal. Combined Chlorine is a bad thing, not a good thing, so having it at or near zero is what you want (and currently have).

Don't worry about your saturation index since you have a vinyl pool so don't need as much Calcium Hardness (CH) unless you've got some exposed grout in tile touching the pool water.

Did you mean 70 ppm for your CYA reading? 7.0 doesn't make sense. The tube only measures from 30 (at the top) to 100 (near the bottom).

You need to raise your pH as well as your Total Alkalinity (TA) so I suggest using Sodium Carbonate which is in Washing Soda (not Baking Soda) or is sometimes called Soda Ash or is in pH Up from the pool store. You need to add 116 ounces (7.25 pounds) of it to your 44,000 gallon pool (that's a very large pool) to raise your pH to 7.5 and your TA will rise to about 70 ppm which should be fine. Add half of this amount and retest pH after a day, just in case your measurements are off. Then add more as needed.

What are you using as your source of chlorine? The low pH and TA and the higher CYA imply that you may have been using Trichlor pucks/tabs. You should stop using those and switch to a chlorine source that does not have CYA in it such as chlorinating liquid or bleach (or Cal-Hypo, but this will increase calcium hardness over time). At your 70 ppm CYA level (if that is your CYA reading -- not the 7.0), then you need to maintain between 5 and 10 ppm Free Chlorine (FC) as seen in this chart in order to prevent algae.

Richard
Thanks, Richard-
I did the combined chlorine test exactly as you described. I put the drops into the preciously used sample and it never turned the water pink again.

As I read your response I went back and rechecked my kit - I actually used the wrong scale on the tube for the CYA measurement. Using the proper scale, my CYA is actually 50. Is this a decent number or does that pose a problem? As for the question of what I'm using for chlorine, I am using the pucks. I'm gone from home frequently and my wife wants NOTHING to do with maintaining the pool. I need something that will auto-dispense while I'm gone. Will another form of chlorine work in my Hayward chlorine dispenser? Are there any other options other than the pucks that I can use to auto-chlorinate my pool? I can't swing the salt to chlorine setup now financially, but is that a better setup that I should work towards?

What brand name is "washing soda" or "soda ash" available as in the stores? Is this the same as Borax? Where can I buy it? I try to avoid "pool store" cures when I can as the tend to be SO overpriced. Is there a calculator available on line or here that shows how you came up with the amount I need? By the way, my pool IS actually 44,000 gallons - it's way too big! We sort of got caught up in the "...for a bit more we can go bigger..." routine. It's our first pool, if we ever move and do it again the new one will definitely be smaller!
Thanks for all your help and patience with this neophyte!
Doug