Crazy FC Reading?

[Siglumous]

So I received my TF-Pro test kit today. I started off with the Daily Test and am not sure how to interpret the chlorine levels. Instead of any shade of yellow, it's very orange and/or red. See photo. Is this just telling me lots of Chlorine (too much) or is there an issue. I took a second reading and got similar results.

I then went on to the weekly reading and got:

FC - 26
pH - 7.5
TA - 110
CH - 375
CYA - 120
TEMP - 85

I'm just into year two of having this pool. The pool was built in 2005 and I've been using the same pool company to maintain it as the previous owner. I had made the decision to start maintaining it myself next season. Any advice what to do next and what to tell the pool guys when they arrive tomorrow? Many thanks!

 

[Texas Splash]

For the FC test, stick with the FAS-DPD (powder & drops) for now. They yellow drops for the FC in the OTO viewer can be a bit confusing until you learn to compare the two testing products, especially when the FC is elevated like yours appears to be now.

But that CYA is your biggest challenge right now. Are you planning to just leave it alone and ride a high FC level until winter, or will you be doing a partial water exchange to lower the CYA?

 

[Siglumous]

Thank you.

So the FC (based on the FAS-DPD) test is likely accurate at 26. And very high. But based on my Pool School studying, my pool guys likely have it high since the CYA is also high. If I'm understanding things correctly, that's "OK", but ideally I'd want to bring down the CYA and then the FC correspondingly.

The pool company uses some kind of puck in the dispenser, so again based on my new/limited knowledge from Pool School, the CYA comes from those pucks.

Should I instruct the pool guys to use chlorine for the rest of the summer or just "ride it out" as Texas Splash asked?

 

[Texas Splash]

my pool guys likely have it high since the CYA is also high. If I'm reading things correctly, that's "OK", but ideally I'd want to bring down the CYA and then the FC correspondingly.

Correct

the CYA comes from those pucks.

Correct. You should pull any pucks from use right away and use liquid chlorine or regular bleach to maintain the FC level. No CYA side effects with the liquid.

 

[Texas Splash]

Unless you already did this, I would recommend performing a "diluted" CYA test as noted in the link below starting at step #8. Your CYA may be higher than you think.

CYA - Cyanuric Acid Test

Cyanuric Acid (CYA) is the chemical name for what is commonly referred to as Stabilizer … Read more…

www.troublefreepool.com

 

[mknauss]

How did you get the 120 CYA level?

 

[Texas Splash]

Remember the one down-side about compensating for a high CYA with a high FC level (to avoid algae) means you'll never really be able to get a good pH test. The pH test is influenced whenever the FC is over 10 ppm.

 

[mknauss]

The ‘pool guys’ will continue to use the trichlor pucks. Only way they can keep your pool ‘clear’.
I suspect they also add baking soda every week to keep the TA high and the pH from crashing.

 

[Siglumous]

How did you get the 120 CYA level?

Well, that 120 was a guess on my part since the marks only go to 100. It was past the 100 mark...and I estimated (I'm now guessing that's a bad thing?).

 

[Siglumous]

Correct


Correct. You should pull any pucks from use right away and use liquid chlorine or regular bleach to maintain the FC level. No CYA side effects with the liquid.

They'll be here tomorrow morning. I'll ask them to remove the pucks and add liquid chlorine--assuming they stock it on their truck.

 

[Siglumous]

I initially had faith my pool guys were doing the right thing. Now I'm even more glad that I've made the decision to DIY next year.

Based on what I saw at pool closing last year, it looks like they empty about a third of the pool. I understand that CYA never reduces without dilution, so should I ask them to lower the level even more--say halfway? We get a bunch of rain here in Virginia so I expect it will fill up/spill over at some point during the winter.

 

[Siglumous]

Well, that 120 was a guess on my part since the marks only go to 100. It was past the 100 mark...and I estimated (I'm now guessing that's a bad thing?).

And now based on Texas Splash's comment asking if I performed a diluted CYA test, I see (again, thanks Pool School) that I can get an accurate reading using that method rather than guess-timating.

 

[mknauss]

Well, that 120 was a guess on my part since the marks only go to 100. It was past the 100 mark...and I estimated (I'm now guessing that's a bad thing?).

Do the dilute test Pat mentioned above. Your CYA I suspect is much higher than 120.

 

[Siglumous]

Unless you already did this, I would recommend performing a "diluted" CYA test as noted in the link below starting at step #8. Your CYA may be higher than you think.

CYA - Cyanuric Acid Test

Cyanuric Acid (CYA) is the chemical name for what is commonly referred to as Stabilizer … Read more…

www.troublefreepool.com

Diluted CYA test came back between 110 and 120. If I performed the test correctly. I'll continue to post readings over the next few days as I get the hang of the test kit.