Test results on new pool in Tucson

[Wilco]

So have been in this house for a month, new pool owner. Hard water here in tucson. Monitoring with guess strips, shocking once a week or so. Seemed to have consistently low ph and low chlorine though. Pretty clear overall, use sand shark vacuum regularly, large triton II sand filter, pebble tec Pool
Is 30' x 20'. Added one box of borax to skimmer, tested with spanking new Taylor kit:
Ph 7.9
tA. 90
CH 380
Cya 110
Free cl o.6
Comp cl 0.6
Sat index 0.6

Water seems good, clear. Anything I should worry about? Thanks.

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[Watermom]

What are you using as your source of chlorine? Your chlorine is WAY too low for a pool with a CYA of 110. (How did you get a reading of 110, anyways? The kit only goes to 100.) If your pool is clear, you are very lucky. You have the perfect conditions for an algae bloom --- low chlorine and high CYA.

With your CYA, you need to be keeping your chlorine between 8-15 ALL the time. And, when you need to shock, your shock level will be 25ppm.

Have you been shocking weekly and then adding no additional chlorine until it is time to shock again? If that is the case, there is a better way to do things. It is best to test every day or two and add enough chlorine to get back to around 15ppm. You want to be able to never drop below 8ppm. You may find that you can go for several days between doses of chlorine depending on how fast your chlorine level drops.
More about the CYA and chlorine connection can be found here:> http://pool9.net/cl-cya/

Your CH and CYA are both high enough. Therefore, it would be best not to use any cal-hypo or any forms of chlorine that have CYA in them such as trichlor pucks or dichlor shock powder. Instead, just use bleach. Many of us use Walmart's generic 8.25% bleach as our source of chlorine. If you tell us the volume, we can calculate a dose reference for you.

Hope this helps. Repost with the answers to the questions and someone here can help you go from there.

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[CarlD]

Hi and welcome!

Just to add to WM's advice: Don't use the 25ml line for your testing of chlorine (FC and CC). Instead use the 10ml line. That way, each drop of the R-0871 liquid will equal .5ppm of FC or CC, and 2 drops = 1ppm. Whereas, with the 25ml line you need 5 drops for every 1ppm--and that uses up your reagent liquid. Measuring to .5 rather than .2 is 'WAY good enough for everything we do here.

[Wilco]

Thank you, I was hoping to get an answer like that and convert to bleach. Initial pool inspection guy set me up with the tricolor pucks, and I've had 4 in a floater consistently, and have shocked with 2 bags of shock 4 times in a month. I think that my hard water is preventing good chlorine saturation. Will the bleach work better? Also, I estimated the cya, as it was just above 100.

[Watermom]

The bleach will not add unwanted things along with the chlorine. If you give the volume of the pool, we can help you determine doses of bleach to add.

[Wilco]

It's about 18000 gallons, spa is 500. Again, I think the excessively hard water here is the X factor. What unwanted additives do the tricolor pucks and dichlorvos shocks add?

[Watermom]

Trichlor and dichlor both add CYA and yours is already too high. For reference --- each quart of 8.25% bleach will add around 1ppm of chlorine and each of the 121-oz jugs will add about 4.5ppm.

[Wilco]

Excellent, thank you. Now what to do with sell the pucks I will have lying around.........

[CarlD]

If you can keep them, in the spring your CYA may well be lower--very common. If not, give them away if you can.

Tri-chlor pucks are GREAT when you have a high pH and low CYA situation as they are very acidic and add 6ppm of CYA for every 10ppm of chlorine.

[Wilco]

Hit it with 4 qts of bleach. Waiting to retest. Any guesses?

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