New to pools generally, need a little guidance

[scubaAZ]

Hi there!

I have been a pool owner for about 6 months, and finally got brave enough (and found this site) to take over from the pool guy and manage our own pool. I'm in Phoenix, AZ, so its very warm here (approximately 108 as a high these days, in the high 80's at night), and the pool gets full sun all day.

The pool guy had been using pucks, so our CYA is fairly high (100, possibly a smidge higher, I'm not so good at the test yet).

Full test results from the T-100 kit:

FC- 24 (more on this in a minute)
CC- 1 (barely sort of turned pink, but it wasn't quite still clear, so I counted it.)
TA- 140
pH- 7.2 to 7.5 (more on this in a minute too)
CYA-100
CH- 800
CSI- .33 (according to poolcalculator.com)

Ok, so here's the thing. We've been doing this for about a month now, and no algae or craziness (knock on wood!)

The pH is a smidge low because the TA was high, and the CSI was high. So I added the acid last night, and will run the fountain tonight to bring the pH up. I think the calcium is so high because we have really hard water out here in the desert, but I'd love to hear anyone else's take on that, and whether its worth replacing water if the replacement water is high in calcium anyway. There is no scaling as far as I can tell (given my whole month of experience with such things!), the tile along the waterline is bright blue, I think it would show there, no?

The CYA is also high, so I've been shooting for 8-12 FC like the TFP recommends for CYA at that level. The problem is when I add the amount of chlorine indicated by the calculator, it ends up WAY higher than what it should be. For example, last night I measured the FC, and it was down to 4 (still working on the timing of adding more!), so the calculator said adding just over 1 gallon of 10% liquid chlorine would get me to 12. Awesome. I test today, its at 24! I did the test twice, I'm (99%) positive that is accurate. Last time we let the chlorine get low (let the pucks that the pool guy had used dissolve, they just dissolved a lot faster than we thought), it was almost zero. Added 2 bottles of 8.25% bleach, which was supposed to get us to 5 but it was all I had on hand. Tested the next day, it was 16. I haven't been measuring every day (I know!) but it seems to be losing 2-3 ppm per day, which I understand is normal, especially given the constant sun.

I'm pretty sure the pool measurement is correct (14, 000 gallons), and I'm following the testing instructions to the letter. What am I doing wrong to be so far off with the chlorine? Is it possible to add too much of the R-0870 powder? The water looks great (better than when the pool guy did it, it was really cloudy before), and is nice to swim in, but I want to get to a more constant level instead of really high/really low chlorine. I also realize it could go from great to a swamp rather quickly.

Final question: we're going to have to drain about 1/2 the water to bring the CYA to a reasonable level. Is this something we need to do right away, or can it wait for a bit? No more pucks, so it shouldn't get any higher, and we lose a fair amount of water through evaporation every day with this heat. Thoughts?

Thank you all in advice for any advice to a newbie. I hope I have all information necessary here. Water temp is 87 degrees. Filters about 7 hours a night (single speed pump). Please let me know if there's anything missing that would help.

 

[kimkats]

I am thinking your pool size is bigger than you think. There is a way to measure it somewhere on this site. I do not know where it is though. Try doing a search.

OR your chlorine is higher % than you think.

Keep us posted on what you find out.

Kim

 

[duraleigh]

The chlorine test is pretty dependable and the amount of powder is not too critical. I haven't done the math (are you using poolcalculator.com?) but I suspect there is a math error in there somewhere.

Test your fill water for CH....let's see how much CH you add when you refill.

The CYA drain is your call. It's a real PITA keeping the FC high and you can never let it slip, but if you are very diligent, you can make it work. Evaporation is irrelevant to both CYA and CH

 

[scubaAZ]

You think the pool is bigger? Wouldn't that mean that the numbers would end up being way lower than the calculator says? We did the ballpark measurements to calculate the size, and came out around 15,000. The pool guy said he had been working from 14,000 gallons so that is what we went with. Its not a huge pool (irregularly shaped, but about 22 feet long and 13 wide (very approximate), depth is probably 4 feet at the shallow end and 8 feet in the deep end). Does 14,000 sound way off? It is an old pool (house was built in 1962, not sure if the pool is from then or a little later), if that makes any difference.

Yes, the calculations are from poolcalculator.com. I would never pretend to do the math myself... my only C in college was in chemistry... Haha! I used the % off the bottles, Clorox for the bleach, and liquid chlorine from Leslies, so I hope they're fairly accurate. I guess at least its way higher than it should be, rather than too low and letting creatures grow in there.

And if no CYA is added, and about an inch of water is replaced per day, that will never lower the CYA? Very interesting. I guess because the CYA doesn't evaporate with the water, it just concentrates more until the replacement water is added back, and so remains the same? I'll have to do the CH test on our water generally and see what the number is. Thanks for the replies!

 

[duraleigh]

Sounds closer to 10k to me. Got a pic?

 

[harleysilo]

With your rough measurements i come up with 13,225 gallons. If the shallow end is closer to 3' and deep end closer to 6' i get 10,158 gallons.

You should measure more exact for us, including actual depth of water so we can figure it out.

 

[scubaAZ]

Here is a picture. I will get real measurements tonight when I get home from work. We measured for a pool cover, but those numbers included overlap on the sides so the guess above is me roughly accounting for the overlap. I'm positive its 8 feet at the deepest part, but it could be 3 at the shallow end. It gets deep very quickly, so there isn't much of a shallow end. By the point where the pool deck juts in on the right (in the picture above), I can't touch the bottom and I'm 5' 7".

I guess if its 10,000, that would explain why the numbers are all crazy

 

[duraleigh]

Yeah, I think that's about a 10-11k pool.

 

[kimkats]

sorry for the duh moment. Logical thinking/speaking is NOT my strong point lol

I MEANT to say that your pool is SMALLER than you think so your results are off.

DUH! Hangs head and sit in the corner LOL

 

[scott.MI]

How did you get CYA of 100? Was it with the normal testing, or the extended test (diluting with tap water? Just wondering if your CYA is actually higher than 100.

If your CYA level is 90 or higher, repeat the test adjusting the procedure as follows:

Fill the mixing bottle to the lower mark with pool water.
Continue filling the mixing bottle to the upper mark with tap water.
Shake briefly to mix.
Pour off half of the contents of the mixing bottle, so it is again filled to the lower mark.
Continue the test normally from step 3, but multiply the final result by two.