Help with best guess chart

After following everyone's advice, I believe I have finally conquered my algae problem. :) :) :)
So now for daily maintenance I am unsure what chlorine levels I should be running. My CYA level is between 80 - 90. So, should I run the max daily FC of 10? If I do that, do I take my FC level to around 12 each night, so that it will be 10 by the end of the day? Also, when would I ever need to bring my FC to the shock+ level?

I live in N.E. Texas so the temperatures are very hot during the day. So I plan on keeping my CYA levels where it is at for now, and let it slowly drop down to around 75, but no lower.

I would say that you need to keep your FC levels somewhere between the 8-10 ppm range for your CYA level. That should be sufficient to keep any growth from occurring. Aylad could probably answer better as I believe her pool runs a CYA of around 90 and she lives in the Shreveport area which would be close to the same temps and climate. I'm sure she'll chime in when she can.

When you test in the evenings, add enough bleach to take the chlorine level back up to 10ppm. If you find that by the next evening when you test again, that you have dropped below 5ppm, take it up to 12 instead. You want to take the chlorine level up high enough so that you never drop below 5ppm. I'd start out by testing every night but after a while, with a CYA of 80-90, you may find that you are able to test and add bleach every other night. But, don't start out that way. And, make sure you stay above 5ppm at all times or else you risk an algae bloom.

With my CYA at 90, I usually make sure there is 9-10 ppm at night when I turn the pump off, and there is usually at least 6-7 left by the next evening. But as Watermom said, if you find that it is below 5 ppm (might happen with a heavy swimmer load, lots of bugs/grass clippings, etc), then just bump it up to 12.

After a few days (weeks) of regular testing, you'll get a feel for how much chlorine your pool normally uses in a day. If you start seeing that useage increase, then you need to test it at night and again in the morning to see if you're losing any overnight. If you are, then it's time to shock the pool--but by catching it when the chlorine demand has just started increasing, you'll be able to shock it and kill off the goo before the pool has the opportunity to turn green again. When you shock it, use the shock level on the chart. The shock+ level is for mustard algae, or for pools that are not responding for whatever reason to the normal shock levels. I've never had to take mine up that high, in 11 years.

@Tim: I would shock the pool if you have CC > .5 ppm. Like Aylad said, you would notice an increased chlorine demand.

Thanks for the help. For the past 3 evenings I my FC has tested between 9 - 10 ppm. I have been taking it up to 12. So it seems to have lost 2 - 3ppm during the day. I will say that the past 3 days have been un-seasonally cloudy with brief rain showers. So there has not been any swimmer activity. Also, I tested my CC this evening since we have had some brief showers, and after adding the 5 drops, the water barely turned pink. And after 1 drop it cleared up completely. (10ml sample) So am I correct in assuming that my CC is somewhere between 0 - 5 ppm? Should I shock right now?

Also, I will start following the advice above and only taking my FC up to 10 ppm each evening, unless I start seeing it fall below 5. The good news is that until Monday, (4 days from now) I will be home during the day, so I can keep up with it if it starts falling too low.

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Originally Posted by tim665214

...So am I correct in assuming that my CC is somewhere between 0 - 5 ppm?

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Right. 0ppm - 0.5ppm or less than 0.5ppm.

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Should I shock right now?

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I don't see why.

We usually don't recommend shocking unless the CC is over 0.5pm.