CYA Question

[bobcat]

Question #1: Once I obtain my CYA level, does it stay the season, or do you have to replinish from time to time?
Question #2: I live in central Texas, it is hot, no..I mean HOT! Pool is in full sun, all day. How high can my CYA safely be?
Thanks for this forum and all your help, Robert

[aylad]

1. Once you obtain your CYA level, it stays the same unless 1)you add more stabilized products, like dichlor or trichlor, or 2) you backwash a great deal or have lots of splashout...although I'll tell you it takes a LOT of either to substantially lower it.

2. I live in Northwest Louisiana, so I feel your heat......my pool is also in full sun all day. I intentionally keep my stabilizer in the 80-90 range, otherwise I can't keep chlorine in the pool. All you have to do is run higher baseline chlorine levels to compensate...see the "best guess table" link in my sig for corresponding CYA/chlorine levels.

3. Thanks for supporting the Poolforum with your subscription!! We really do appreciate it.....

Janet

[bobcat]

Thanks Janet. I have put in 4 lbs of stabilizer ($25) and still can't keep chlorine. Been adding a gallon every night. I have some pucks left over from last year before I switched to BBB, so I bought a floater at Walmart today and will try that route for a few days. Hate to waste more $$ on pool store conditioner since I have the trichlor. I know...got to watch the ph while using the pucks. Taylor kit from Amazon should be here today or tomorrow and I will post full set of numbers. I'm out of regents on old Walmart test kit, but last check (5 days ago) for CYA the dot never disappeared. Good news is water is cyrstal clear!

[bobcat]

Janet, one more question. If I'm reading the "best guess chart" correctly, If I get my CYA somewhere between 60-90 (for the Texas heat), then my chlorine level would need to be between 5-10. Correct?

[Watermom]

Yes, you are correct. If you let it drop below 5ppm, you risk an algae bloom.

[bobcat]

By golly...think I'm starting to get the hang of this. Thanks to all of you!!!

[bobcat]

Just got my Taylor test kit, here are the numbers:
FC: 1.5
CC: .5
CYA: 0 (turns cloudy but dot never completely dissapears)
PH: 8.0
TA: 175
CH: 200
New liner, new water 2 weeks ago. Only thing added is blech (Walmart 6%) and stabilizer (4 lbs granular hung from sock over return). Test done about 8:30 am this morning. I understand low chlorine level from no CYA build up yet. Bought another 4 lbs of stabilizer and will hang sock over return again. Why is ph so high, and is this a problem? What about the other numbers? Thanks for all your help so far, Robert
Don't see my signature so here is other info: AG 32x16x4 (14K) Pentair 1.5 HP, Sand filter.

[CarlD]

OK.
First, it's usually good to test your fill water, especially for FC, CC, pH, TA and CH (no need to check CYA).
You may have very alkaline water to start with. You already know you probably have hard water based on your TA and CH reading.
Second, with your very high TA, if you are getting a lot of splashing in your pool, or have a windy location, aeration may be driving your pH up. See below.

With your high TA, which isn't usually a problem in an AG pool, you can lower it and probably solve your pH problem at the same time.
Simply add muriatic acid or dry acid to your pool to lower your pH to the 7.0-7.2 range, but NO LOWER (or risk damaging your liner). TA will come down some. Then aerate to raise pH to 7.6-7.8.
(bubbling, splashing etc causes "gassing off" of carbonic acid as CO2 and that raises pH without increasing TA. Chemical pH raisers, even Borax, will raise TA some as TA is "connected" to pH and moves with it. Aeration "cheats" that connection)
Repeat this process until TA is in the 80 to 120ppm range. You should notice that the tendency of the water to high pH level stops. If not, lower to 70-90ppm. (I keep mine at 60 because my pH has stayed locked in at 7.6 for about a month solid now).

I would consider taking out the second sock of CYA and checking again. Your CYA level isn't 0 but all we know for sure is that it's less than 30 and probably less than 15. The sample got cloudy which means you have CYA but the dot didn't disappear--so it's low. CYA can take a long time to get into your system and you shouldn't backwash for up to a week after adding it. In any case, you should check your CYA at least once a week. (I buy extra pint bottles of R-0013 and keep them in a cool dark place so I always have plenty of reagent.)

If you take out the sock and your CYA is still low and your pH is still high, for convenience you MAY consider using a floater full of Tri-chlor tablets. Tri-Chlor is HIGHLY acidic and for every 10ppm of chlorine it delivers, it adds 6ppm of CYA to your water. The 1" dissolve faster delivering a bigger "hit" of chlorine, and getting acid and CYA into the water faster. IF you go this route remember you MUST test your FC and pH daily and your CYA weekly. Also do NOT get any that says "Double Acting" "Also contains algaecide" or has copper listed as an ingredient.

However, you can do EVERYTHING with what you have and don't need to spend the money on tri-chlor.

Carl

[bobcat]

Thanks Carl. I live in Central Texas and the wind has been crazy here, blowing 25-35 daily, so maybe that's one answer to the high ph. When you say "you can do EVERYTHING with what you have", did you assume I had muriatic acid? If I understand you correctly I need to add that to lower my ph and TA at same time. Where can I get muriatic acid? Is it called anything else? And, is 8.0 a problem, since I have grandkids over and will be in pool this weekend? Thanks, Robert
ALSO: Is there any danger with swimmers in the pool after I add the muriatic acid?

[Watermom]

Robert

it gets really difficult and confusing to have two threads going at the same time. Whoever is helping needs to be able to see the history of the issue and also the advice being given by others. So, I merged the thread you started today with the other one you've been using for the past few days. Hope you understand.

Thanks.