New pool water

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K

Karkas

0
Apr 5, 2018
7
Phoenix, AZ
Pool Size
10762
Surface
Plaster
Chlorine
Liquid Chlorine
Hello all, this is my first post here. I've been reading a lot, but still a little vague on a lot of the chemistry.

I bought my house a little over two years ago and it already had a pool. I just drained it this past winter, because the CYA levels were probably in the 200+ range. I learned my lesson and wont be using any tabs or the powder bag shock.

Now it is refilled and I am balancing the water.

Here are my current test results:

FC = 6.5
CC = 0
pH = 7.8
TA = 160
CH = 250
CSI = 0.38
CYA = ~25 (I just added a few more pounds today)
Water temp = 70 F

I ordered 25 lbs of boric acid yesterday and intend to add that to the pool next week. According to the calculator it should bring my level to around 44.

Before I add the boric acid, I was wondering if I should add some acid to bring the TA down? I see a lot of references to "high and low TA" but I don't really know what I should be shooting for.

Also, it says on this site that a ph of 7.8 is ideal, but everywhere else I look suggests that that is on the high side.

Finally, I am waffling on what CYA I should shoot for. I'm terrified of it getting out of control again (I was dumping a gallon of 10% bleach in every other day just to keep the FC above zero). I see CYA recommendations all over the place. I was originally wanting it low, so a lower FC would be required, but since I live in Arizona, I'm concerned about the sun destroying chlorine too.

With all the sun in AZ, should I be shooting for a slightly "high" CYA of 60 as some local pool shops recommend? I don't want to spend any more than I need to on chlorine.

Thanks in advance!
 
If your fill water is ~250 on CH you are lucky. AZ has some of the hardest water around I believe and most of our AZ friends have to fight it constantly.

7.8 is just fine for pH. If you knock that TA down it will help your CSI and any pH rise you may see. I would agree with Arizonarob, don't be afraid to go up to 50+ for CYA it will help a lot.
 
Bruce - 250ppm is what most of us have here, and it causes a very rapid rise in CH since we're also subject to an extraordinarily high-evaporation rate. Hitting 1000ppm CH doesn't take long here. :)

OP: 50-60ppm of CYA is a good number here. I usually start the season at 50 so I can use tabs for vacations at least once without getting too high.
A pH of 7.8 isn't bad. Since we often work with higher CH levels in our pools here in AZ, this will be a situation where you want to watch your CSI number - that can be found on PoolMath (link at the top of the page). Try to keep it around 0 if possible (this will requiring higher pH until the water warms up for the season, then it may require lower pH). Borates will have an effect on this number, so before adding that boric acid, you'll want to make sure your like your TA number and you're comfortable with what it will do to your pool at pH 7.8 with a water temperature of 90 degrees and CH of 400-500. Don't be hasty with borates!
 
Thanks for the responses and yes, I expected a higher CH level as well.

It was my first time doing the test, so I am going to re-test tomorrow and swirl more vigorously as there were some undissolved particles in there and I'm not sure if they threw off my results.

I think I'll see where my CYA level settles after adding more in this morning... I'm guessing it will be around 40 or so, but that's just a guess, because I'm not weighing it out as I add it. I'll take daily readings to see how fast the chlorine is getting consumed, then I'll increase the CYA up to 50 and see how that effects it. If it saved a decent amount of chlorine, I'll bring it up to 60.

Thanks again and I welcome any other comments :)
 
In that case, do not add any more for about a week or so. Also, no backwashing for a while. You definitely don't want it sitting in contact with your pool bottom for any length of time.

Adding it directly to the pump via the skimmer means your filter now has a bunch of undissolved CYA in it. Adding more CYA now means you may end up much higher than you wanted to be. Keep the pump running 24/7 for a few days to dissolve the CYA that is in the filter and then retest.

The best way to add CYA to a pool is to put it into a sock for your foot, and either suspend it in front of a return (so that it is not touching the side), or put the sock in your skimmer basket and leave the pump running. Every half hour or so, massage the sock with your hands until the white cloud stops coming out, then let it soak, and repeat. You can dissolve pounds of CYA in a few hours this way and rest assured that you don't have piles of it waiting to dissolve in your filter system.
 
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