Very high Cyanuric Acid with no obvious reason

[melinbaja]

You are better off to use a sump pump. Can you buy one in your location? Could you put where this pool is located in Mexico in your profile?

As long as you do not drain more than 18" or so your liner should be OK. There is an exchange method but you need a sump pump.

Thank you. Can you please explain exchange method? I'm thinking it is pumping out from the bottom of one end and filling at the other end?

I will be getting water trucked in as we are not allowed to use our well water for pool filling.

I shocked two nights ago with AquaChem Superclorinacion (Dichlor). This afternoon the AquaChek7 strips read:

Total hardness: 1000
Total Chlorine: between 0.5 and 1.0
Free Chlorine: 0.5
pH: 8
Total Alkalinity :close to 240
Cyanuric Acid: 250-300

The well water we use to fill and top off the pool reads (Using Aquachek7 strips) :

TH: 1000
TC: 0
FC: 0
pH: 8
TA: 240
CYA: 30-50

The strips have always worked well for me for years. I just received 4 new bottles expiring 12/2020 and am using those. Tossed the prior ones expiring 01/2020.

I so appreciate this community and folks taking the time to give me your thoughts.

 

[justinc]

When you get your TF-100 and you do a test and compare those with the strips you will throw the rest of them away too. Just looking at the latest test strips you used, it shows your well water has cyanuric acid. I don't even think that's possible.

 

[mknauss]

I don't even think that's possible

It is not possible.

The exchange process is a slow process. Normally in the 7-15 gpm rate, depending on your sump pump capability. I do not see how you can do it with truck in water. In your case, you will need to drain the pool and refill with the truck. I do not remember your risk issues but you will need to manage them.

Your fill water has TH 1000?? I cannot see how your fill water is the same as your pool, unless you do not use the fill water to actually fill the pool. Again, questionable test strip results.

 

[melinbaja]

It is not possible.

The exchange process is a slow process. Normally in the 7-15 gpm rate, depending on your sump pump capability. I do not see how you can do it with truck in water. In your case, you will need to drain the pool and refill with the truck. I do not remember your risk issues but you will need to manage them.

Your fill water has TH 1000?? I cannot see how your fill water is the same as your pool, unless you do not use the fill water to actually fill the pool. Again, questionable test strip results.

Thank you for your replies!

Maybe the CYA in the well water comes from the mild chlorine that is put into our very large water storage tank. I think they use tablets or granules.

I have just checked the incoming water coming from our well again with the doubtful test strips. This morning it shows

TH - 500-600
TC - 0
FC - 0
pH - 7.8 - 8.0
TA - 240
CYA - 15

The well water is stored in a very large tank for the community and gravity-fed to each lot in our subdivision. They do put something in that adds chlorine to the storage tank. I will try to find out exactly what that is.

I fill my pool from a hose using the well water but I have a scale-stop filter on that line that has helped keep the mineral deposits at the water line down very well.

It is filtered about 12 hours a day with the solar pump at an average of about 10PSI.

It will probably be another 8 or 9 days before my TF100 kit gets here. I will be leaving for the summer soon and want to have this figured out before I go. So my plan is to pump out 15 inches or so, about 5,000 gallons, and have it filled immediately with trucked water. It will come in two trucks of 10,000 liters each. I'm ordering from two different water guys so we don't have to wait for one to go refill. (My maintenance person is coming today to try a couple of methods for draining - using an external 1.5 hp pump or a submersible pump. )

We are planning this for tomorrow. Hopefully this won't be a risk to the liner. That is my biggest concern.

If there is a better way to accomplish this, or if you think it is too risky for the liner, I'd appreciate your thoughts.

Is there somewhere that describes the exchange method?

Thank you all so much for sharing your ideas.

When you get your TF-100 and you do a test and compare those with the strips you will throw the rest of them away too. Just looking at the latest test strips you used, it shows your well water has cyanuric acid. I don't even think that's possible.

 

[mknauss]

You can exchange some water without draining.

If you place a low volume sub pump in the deep end and pull water from there while adding water in the shallow end (through a skimmer or into a bucket on a step so you lessen the water disturbance) you can do a fairly efficient exchange. That is assuming the water you are filling with is the same temperature or warmer than your pool water. If your fill water is much cooler than your pool water, then switch it. Add the water to the deep end (hose on bottom) and pull water from the top step.

The location of the pump and fill hose may change if you have salt water, high calcium, etc.
In my pool, with saltwater and high calcium when I drain, I put the pump in the deep end and hose in shallow end. The water in the pool weighs more per unit volume than the fill water from the hose.

Be sure to balance the water out and water in so the pool level stays the same. Also be sure your pool pump is disabled during this process. Once started do not stop until you have exchanged the amount of water you wish.

 

[melinbaja]

Thank you for this detailed explanation.

Unfortunately I cannot refill through a hose from our community well/storage tank, which is how I top off my pool. It's against the rules to use that volume of water in one day. I must use trucked water. Which makes the exchange idea difficult, I think. They can adjust the pressure some, but it will be a hard flow compared to a hose.

I'm very nervous about doing this right. I really appreciate your experienced ideas!

 

[melinbaja]

Update: Today we used a powerful external pump to quickly remove 6,800 gallons of my 16,000 gallons and immediately replaced it with trucked water. The water level ended up below the skimmer, stairs and both returns. We had closed all the valves near the pump and filter, and the pump started beautifully.

Using the AquaChek 7 strips the new water was
TH -- 250
TC - 0
FC - 0
pH - 7.6
TA 180
CYA - 0

It's been filtering the combined water 2 hours and the test strips show
TH 1000
TC 0
FC 0
pH 8
TA 240
CYA 150

The Taylor FAS-DPD test shows the TC to be 1.6 and FC 1.2

I'll know more when the FT100 kit arrives in a week. Looking at PoolMath, I think I should add 4 cups acid today and 1 gallon of Clorox tonight.

I also have some lithium shock left. Non-chlorine shock is on the way, maybe 2 weeks out. I don't want to use the dichlor shock as that adds CYA, correct?

Any thoughts you'd care to share would be very much appreciated!

THANK YOU ALL!

 

[mknauss]

Really no comment from me as you are using strips. IF your CYA and CH are that high, you need a 50% plus water exchange again.

And if you are going to use non-chlorine shock (MPS) in this pool you need a different test kit for that. MPS messes up the FC/CC test.

 

[melinbaja]

Really no comment from me as you are using strips. IF your CYA and CH are that high, you need a 50% plus water exchange again.

And if you are going to use non-chlorine shock (MPS) in this pool you need a different test kit for that. MPS messes up the FC/CC test.

I'm anxiously waiting for the arrival of the TF100 kit and CYA test kit. Another week probably.

I was thinking the lithium shock without stabilizer was a good option. I have about 3 treatments left of that.

And what test kit would you recommend I get if I then use MPS?

I did add 4 cups of acid Thursday and 1.5 gallons of Clorox Thursday night. One more gallon of Clorox last night. Total Clorox since replacing 26,000 liters of water: 2.5 gallons.

Strip readings this morning:

TC 4
FC 3
pH 8
TA 240
CYA 200

I know, but they are all I have until the kits arrive.

Thanks again for your thoughts!

 

[justinc]

I don't know if Clorox in Mexico has the "Cloromax" additives, but be careful with that. If you have just a basic bleach at your local store it would probably be best to stick with that. No low splash, no scents, nothing but basic bleach. In the United States, Clorox has added some additional chemicals to their bleach which is not good for pools. Do you have access to a pool store locally that can sell you a drop based test kit? That would give us some starting points to work with until you get your TF-100. It's too risky to add anything other than bleach really until you get your kit or some form of drop based kit. You said you replaced the water but the test strips show a CYA of 200. Surely you did not add 200 CYA. That shows you how off the strips are. Again, too risky to dose based off of strips. Need results from a drop based test kit or the TF-100. As far as using MPS based shock, I just don't see the advantage to using that. It will mess up your results and you have access to bleach which will do the same thing...

 

[mknauss]

How to test MPS with TF100

I use the TF100 for my testing. I have the Nature 2 and use MPS. I have used test strips for the MPS, but would like to start using the TF100. I believe I have seen posts on how to do this, but haven't been able to find them. Can someone tell me how to test MPS with the TF100 or link me to a...

www.troublefreepool.com

Lithium shock should be OK. Just crazy expensive. And I believe getting very hard to find in the USA.

 

[melinbaja]

How to test MPS with TF100

I use the TF100 for my testing. I have the Nature 2 and use MPS. I have used test strips for the MPS, but would like to start using the TF100. I believe I have seen posts on how to do this, but haven't been able to find them. Can someone tell me how to test MPS with the TF100 or link me to a...

www.troublefreepool.com

Lithium shock should be OK. Just crazy expensive. And I believe getting very hard to find in the USA.

Yes it is. I have not found it anywhere. Shopping online, but sites say no longer in production due to lithium being used in batteries, etc.

Do you think I should just keep using Clorox until I get my TF100 kit and can really know my numbers?

If anyone knows where I can order lithium shock, please share!

Thanks.

 

[melinbaja]

And thank you for the MPS testing info!

 

[mknauss]

Keep using bleach/liquid chlorine.

Are there no cleaning supply stores in your area? Feed stores, etc? Sometimes you can find plain bleach in odd places.

 

[melinbaja]

Keep using bleach/liquid chlorine.

Are there no cleaning supply stores in your area? Feed stores, etc? Sometimes you can find plain bleach in odd places.

Good thought. I'll try those.

 

[melinbaja]

Update: my CYA test kit finally arrived. I could use some guidance on what counts as "you can no longer see the black dot in the bottom of the tube." The dot disappears at about 150 CYA but there is a shadow still visible to about 108 CYA when there is NO shadow that can be seen. Is my reading then 108? It's pretty subjective, looking down inside the tube. But two of us agreed.
Thank you!

 

[mknauss]

Once you have your solution ready, back to the sun, etc. Fill the vial to a line, say 80, lower the vial to your waist level and glance for the dot, you see it, add solution to the 70 line, glance, see it, repeat until you no longer see it with a glance. Then use the CYA value one step above the line you read. So if you stopped at 50, use 60 ppm CYA.

The vial is in logarithmic scale. So it is not viable to interpolate between the lines. Just use the whole numbers, such as 50, 40, 30, ....

If your CYA is at 90 or above, then do a diluted test. See Step 8 in CYA - Cyanuric Acid Test - Trouble Free Pool

 

[melinbaja]

Hello.

We spent the day in Cabo San Lucas looking for liquid chlorine (besides Clorox) and found none. The pool stores and services all use tablets or granular triclor.
We did find at Home Depot a line of products from Aqua Pool. All have stabilizer in them except this one, Hit OK, superchlorinator. No where on the label is the word stabilized or stabilizer nor cyanuric acid. I have tried to get a message with my question about the contents of this product to them via their website but it bounces back, undeliverable. I also tried to contact Home Depot but one person said it has it and one person said no.
Does anyone know anything about this product? Before I use it in my pool I would like to know the contents.

Because our CYA is still over 100 using the TF Test kit, we plan to swap out another 26,000 liters of water on Tuesday for trucked water. Then we will do the full TF100 testing.

Does this sound like a good plan? We are leaving for the summer and our caretaker is good but not an expert on pool water. I really want to have things stable before we go.

 

[ajw22]

Aqua Pool Hit OK has to have either CYA or Calcium in it to bind the chlorine to.

Once you get your TF-100 mix up a bit of Aqua Pool with house water. Test the mixed water for CYA. If the mixing bottle gets cloudy at all it shows you have CYA in the Aqua Pool. CYA does not naturally occur in water.

If no CYA then test your house water for CH using your TF-100. Then test the mixed water for CH. You should see higher CH in the mixed water.

If it has CH then it will introduce a different set of problems. High CH can cause scaling to occur.

 

[melinbaja]

Aqua Pool Hit OK has to have either CYA or Calcium in it to bind the chlorine to.

Once you get your TF-100 mix up a bit of Aqua Pool with house water. Test the mixed water for CYA. If the mixing bottle gets cloudy at all it shows you have CYA in the Aqua Pool. CYA does not naturally occur in water.

If no CYA then test your house water for CH using your TF-100. Then test the mixed water for CH. You should see higher CH in the mixed water.

If it has CH then it will introduce a different set of problems. High CH can cause scaling to occur.

I've tested CYA and calcium as described above and AquaPol Hit OK does have CYA. I have replaced about 13,000 gallons of my 16,000 gallon pool water over the past 2 weeks. I am leaving for the summer and wonder if I should shock before I go. I don't want to use the granulated products I have as they will raise the CYA. Can I shock with Clorox (no liquid chlorine available anywhere around here) ? If so, how much would I need to do the job? Or will sing the Aqua Pool Hit OK to shock cause a problem with the CYA?

Tonight my readings are:
Total Hardness: 600
Total Chlorine: 2
Free Chlorine: 1
pH: 7.8
TA: 200
CYA: 120

I plan to add a gallon of Clorox to get the FC up a bit. I will retest tomorrow.

Thank you!
Melanie