First TF-100 test results and I need help

Jun 8, 2012
6
0
Southern, NJ
#1
Hi

EDIT(after typing this): Sorry about the long post!

This is my first post. I've been lurking for a while and reading a lot on the site. I really appreciate having a site like this to go to and thank you all for sharing your wealth of knowledge.

The background on my pool situation is this. I moved two years ago from a house with a 15' above ground pool that required very little effort to maintain to a house with an in-ground pool. This is my third pool opening on the in-ground since moving. The first year was a blur but I was mostly happy that the pool didn't use much chlorine. The second year it dawned on me that this was a problem. Other than shocking I've only used about a 1/3 of a bucket of 3" tablets for the first two years combined! The free chlorine level is always over 10 ppm.

I've always taken the water to the pool store for testing and taken daily ph and chlorine checks myself. The pool always needed Alki and ph increase on opening, after that the pool has always sparkled and never had any algae. Last year I mentioned to the pool store that I never add chlorine, other than shocking, and that the chlorine level always stays high. They said it was because my stabilizer level was too high. It read over 100 last year. They use the computer testing machine that read the dip strips.

So fast forward to this year, after all of my reading on this site, I was prepared to do partial water changes to lower the CYA level after the pool was opened. I took off the cover, the water was a little cloudy but I could see the bottom. I added one 5 gallon liquid chlorine from the pool store and let filter run for 24 hours. The next day the water was mostly clear but something was off so I took a sample to the pool store and found I needed the alki and ph increase once again. They recommended 30 lbs of alki increase, I put in 20 lbs and waited to retest the next day. The next day the pool water was crystal clear and sparkling. That was 2 weeks ago and the chlorine level has not dropped yet. I went back to the pool store and did a water check, it came back perfect they said. Here's the results:

TC = 10 (max reading)
FC= 10 (max reading)
pH= 7.2
TA= 100
CH= 100
CYA= 30

I asked about the CYA drop from last years reading of over 100, they said it could be from evaporation and rain, they have seen it before. I find that hard to believe in a 25,000 gallon pool. I was at my wits end with the pool store and ordered the TF-100 test kit I read about here. It arrived last night and here are my first results. I'm pretty anal about test procedures so I didn't have too much trouble with the readings, believe it or not the pH was probably the toughest for me. The CYA test is pretty tricky so I repeated it a few times and even surprised myself each time it read the same. The TA test was also a little tricky as the color blipped red earlier in the count but I assumed it must stay red when you end the drop count, please correct me if I am wrong.

The water temp was 76.
TC = 17
FC= 16
pH= 7.5
TA= 160
CH= not tested
CYA= 80

The pool water is still perfectly clear but I need to know what to do about the high chlorine level and the lack of chlorine usage. I should probably bring down the TA also?

Thanks again for helping me out
John
 

JasonLion

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May 7, 2007
37,879
5
Silver Spring, MD
#2
Welcome to TFP!

Pool store test results are routinely wrong, nothing surprising there. Trust your own results and ignore theirs.

CYA does vanish over the winter often enough, but that does not appear to have happened to you.

With CYA at 80 you want FC between 6 and 11. Yours is higher, but still well below shock level. You are fine to swim and can simply stop adding chlorine until FC gets down to something more reasonable. At high CYA levels chlorine lasts longer, which is why FC is coming down so slowly. Lowering your CYA level would be nice, but isn't essential. If you do get algae at that CYA level it is going to be very difficult to get rid of it. On the other hand, CYA will come down slowly, and you can get by with CYA at 80.
 

Thinkly

Well-known member
Oct 12, 2009
298
0
#3
High CYA or stabilizer, will cause you to need more chlorine not less. If you are suggesting that your pool always has a high FC number I don't think there is anything that will cause this except for the addition of chlorine. Regardless your results indicate you have a combined chlorine of 1, which means your pool needs shocking. So perhaps your greatest problem is that you don't have enough chlorine in your pool rather than too much.
 

aa62579

Well-known member
May 24, 2011
409
0
39
North Central Texas
#4
Your Hayward tablet chlorine feeder that you list in your signature is just going to keep raising your CYA level if those are tri-chlor tablets. Do you have it loaded up? That is what is adding the chlorine to your pool. You would need to stop it or turn it to zero to let your FC drop.
 

frogabog

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Jul 16, 2010
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48
Portland, Oregon
#5
My question would be whether or not you plan to continue use of the chlorine feeder and trichlor pucks. If so, 80ppm CYA is actually too much. My other question would be can you turn the feeder down? You say chlorine remains in the pool, but you haven't said you turned the feeder down or stopped using it. My take on it is that if you continue to add chlorine to the pool at the same rate, it's hard to question why it's not reducing. If you turned the feeder off and remove the leftover pucks, and chlorine remained high then there'd be good reason to suspect something is wonky.

I agree that with 1ppm CC it's time to begin shocking, and to stop using pucks entirely. Pucks are best reserved for vacations. I think perhaps 2 weeks ago your CYA may have been lower than 80, but not 30. However, in the time since you did that test you've likely increased it some with the pucks and you should trust your results over the pool store's. I'm sure they've seen lots of inexplicable events occur with their vast knowledge of pools and satisfied customers who spend money on snake oil... It's so comforting knowing they've seen it before but have no answer. :~}
 

duraleigh

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Apr 1, 2007
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#6
Since your FC is already somewhat elevated, I would not shock the pool just yet but rather do the FC and the CC test in a couple of days and see if your CC hasn't dropped below the 1.0ppm mark. There is a good chance it will.
 
Jun 8, 2012
6
0
Southern, NJ
#7
Thanks for all the replies. I'll try to answer all the questions in this one post before I do anything with the pool. I must not have been too clear in my original post, I know it was too long, but I mentioned I've only used 1/3 of a bucket of pucks in my first two years. I haven't used any yet this year, the feeder is empty. I've only shocked with the 5 gallon liquid chlorine. That was 2 weeks ago and no chlorine in any form has been added since. This year I plan on using liquid chlorine only until the CYA is in check. What's my next move? Wait or shock? If shock I see from the CYA/chlorine chart I should shoot for at least 31 FC. Correct? Thanks again!
 

frogabog

LifeTime Supporter
Jul 16, 2010
1,578
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48
Portland, Oregon
#9
5 gallons of 11% chlorine would only raise your pool from 0ppm to 20ppm. Two weeks ago, at 20ppm and now at 17ppm with 1ppm CC? No pucks... something's definitely wonky here.

Did you check the chlorine before you added the 5 gallons? It's entirely possible that you opened the pool with chlorine still in it and when you added 20ppm it really was more like 30 or 40 total. Two weeks with a loss of 3ppm is really quite silly to imagine possible. It had to be over 0 when you added the 5 gallons.

To shock or not... well technically you're shocking right now if it's above 15ppm so I suppose you can just maintain that till you see <1ppm CC and no loss overnight since you're already clear. Or, let the FC fall to your maximum target of 7ppm and see if the CC reduces as well. Watch the daily loss and dose with bleach every night to get back to target maximum. If you lose less than 1ppm/day with no CC I guess count yourself lucky and go with it. No more pucks though, that could kill your bliss :~}

At minimum keep testing frequently so you actually know what's happening and plan to BBB this season. Don't test for CYA every time though. Run CYA again in a week to confirm. With more test results you'll have a much better idea of what's going on. When you BBB, you know what you put into the pool and your test results should match. Who knows how much chlorine those pucks release at any given moment really. Too much guessing for me.
 

Thinkly

Well-known member
Oct 12, 2009
298
0
#10
The only thing I might suggest is that you have only had a reliable test kit for a very short amount of time. When you say that you have always had high FC readings without adding chlorine, this might indicate that your other testing methods were flawed. That or you have a chlorine fairy popping in at night, while you are sleeping.
 
Jun 8, 2012
6
0
Southern, NJ
#11
Before getting the TF-100 this week I always tested chlorine with the OTO test for combined chlorine. I have replaced the chemicals a couple of times along the way thinking they might have gone bad, but all my OTO readings were darker than the highest point on the comparator so that was never an issue. I just didn't know my FC level with that kit.

I haven't done the overnight chlorine test yet but I did test chlorine yesterday. The FC is down 1 to 15. CC seemed to be 0 but looking at the clear test after about 1 minute it turned just the slightest shade of pink, I put one drop back in and it stayed clear so is the CC zero or a.5?

I'll try and get the overnight test done tonight.

Thanks again folks!
 
Jun 8, 2012
6
0
Southern, NJ
#14
I passed the overnight chlorine test, it did not drop from 11. Came home from work today and FC= 7.5. We had two warm and sunny days that helped with that i'm sure. It appears to be going well now that I know what is happening using the TF-100 kit. Since CFA= 80 I'll start adding liquid chlorine to keep my FC level between 6 and 9.