Hi everyone. I have had my pool for several years now but just bought a new TF-100 test kit. My signature shows the test results. Obviously, the CYA level is way too high. I have been using Trichlor tablets since I installed the pool. What do I do to lower the CYA level? Do I need to partially drain the pool or can I just start using bleach instead of the tablets. Water is clear and do not have an algae problem.
New Test Kit
- Thread starter Fredo
- Start date
Welcome to TFP!
There are a couple of problems here which require fairly drastic actions. Before doing the things I describe below, you should probably confirm that your test results are accurate. For the TA test, try doing the test again while wiping the tip of the dropper bottle with a damp tissue ever few drops. For the CYA test, make sure you are doing the test in direct sunlight with the view tube shaded by your body and that the black dot disappears completely, with no sign that it was ever there even after you stare at it for several seconds.
I recommend that you replace water to bring down the CYA level. You may be able to go for some time with CYA at that level, but once you do have a problem, it will be very difficult to recover from as long as CYA remains that high.
Your PH, TA, and CH levels are also high, especially TA. That puts you at serious risk for calcium scaling. Water replacement is likely to help with that as well. In any case, you should lower PH to around 7.0 to 7.2 right away.
There are a couple of problems here which require fairly drastic actions. Before doing the things I describe below, you should probably confirm that your test results are accurate. For the TA test, try doing the test again while wiping the tip of the dropper bottle with a damp tissue ever few drops. For the CYA test, make sure you are doing the test in direct sunlight with the view tube shaded by your body and that the black dot disappears completely, with no sign that it was ever there even after you stare at it for several seconds.
I recommend that you replace water to bring down the CYA level. You may be able to go for some time with CYA at that level, but once you do have a problem, it will be very difficult to recover from as long as CYA remains that high.
Your PH, TA, and CH levels are also high, especially TA. That puts you at serious risk for calcium scaling. Water replacement is likely to help with that as well. In any case, you should lower PH to around 7.0 to 7.2 right away.
Thanks Jason for the tips. I retested CYA and the results were the same, around 100ppm. I retested the TA, wiping the tip of the dropper bottle this time, and got a reading of 200.
How much of the pool water should I replace? 1/3, 1/4? I should lower the PH to around 7 using acid? Thanks agian for the help.
FC 3.5
CC 0.0
pH 7.8
TA 200
CH 440
CYA 100
How much of the pool water should I replace? 1/3, 1/4? I should lower the PH to around 7 using acid? Thanks agian for the help.
FC 3.5
CC 0.0
pH 7.8
TA 200
CH 440
CYA 100
Yes, lower the PH with acid. You don't have to hit a specific number, just get the PH down significantly, but still 7.0 or higher.
I suggest replacing about 1/3 of the water.
I suggest replacing about 1/3 of the water.
You don't want to swim when PH is below 7.2, but otherwise it won't cause any problems down to 7.0. Your TA is very high. Lowering PH will case the TA to come down, and the high TA level will cause the PH to come back up fairly quickly on it's own. It will probably be back to 7.2 quite quickly. Lowering the PH a lot right now is important because you are well into the range where calcium scaling is likely and it is important to get the PH down fairly quickly in order to prevent that.
You don't really need to hit any specific PH number, anything from 7.0 to 7.4 will do, though the lower end of that range improves the odds of avoiding calcium scaling a little.
You don't really need to hit any specific PH number, anything from 7.0 to 7.4 will do, though the lower end of that range improves the odds of avoiding calcium scaling a little.
Jason, after replacing about 1/3 of the pool water, adding acid and liquid chlorine, my signature shows the new test readings. TA still looks high and CYA is still high. What would you suggest? Reduce the pH for a while agian? Replace more of the pool water?
FC 5.5
CC 0.0
TC 5.0
pH 7.5
TA 160
CH 340
CYA 90
FC 5.5
CC 0.0
TC 5.0
pH 7.5
TA 160
CH 340
CYA 90
Hey Fredo, can I make a suggestion? Take the test results out of your signature and just post them in the posts. What happens, is that when we read the posts and look at your test results we don't see where you've come from, all we see is the latest tests. For example, It makes it confusing when you're talking about very high TA and all we see is that your TA is 160.
I recommend replacing more water. Although CYA at 90 is livable, it is still annoying.
On TA, your TA level is getting much more reasonable. At this point, I suggest lowering PH to 7.2 any time it gets up to 7.8 until TA is below 100. That will take a while, but you are no longer in any rush about this.
Remember that the normal day to day FC range with CYA at 90 is between 7 and 10, so your FC level is currently too low.
On TA, your TA level is getting much more reasonable. At this point, I suggest lowering PH to 7.2 any time it gets up to 7.8 until TA is below 100. That will take a while, but you are no longer in any rush about this.
Remember that the normal day to day FC range with CYA at 90 is between 7 and 10, so your FC level is currently too low.
Ok. I added bleach. Here are the latest test results. I have not yet replaced water as Jason suggested. I will replace 1/3 of the water in my pool this coming weekend.
Isnt the Fill water T/A abnormally high?
FC 10.5
CC 0
TC 5
pH 7.8
T/A 160
CH 290
CYA 90
T/A (Fill water) 210
CH (Fill water) 130
Isnt the Fill water T/A abnormally high?
FC 10.5
CC 0
TC 5
pH 7.8
T/A 160
CH 290
CYA 90
T/A (Fill water) 210
CH (Fill water) 130
High, but not unusual 
For reference, my fill water TA is around 300 and CH is in the 350 area
What it means, is that you'll likely be a user of muratic acid to lower TA and manage PH, but is certainly manageable
For reference, my fill water TA is around 300 and CH is in the 350 area
What it means, is that you'll likely be a user of muratic acid to lower TA and manage PH, but is certainly manageable
So, now, I need to add muratic acid to lower the pH. I will lower it to around 7.2 and do this everytime the pH gets up to 7.8. This should lower the T/A over time. In addition, I will replace about 1/3 of the pool water agian to lower the CYA and CH levels. Also, as the CYA value goes down, likewise, I will lower the FC level which corresponds to the values on the "CYA / Target FC chart". Is my logic correct?
I would like to add Borax to my pool. I calculated around 16 Boxes of Borax. Can I add the 16 boxes over time, say 4 boxes, and another 4 boxes in a couple of weeks and so on. All the while adjusting the pH to the proper levels?
FC 5
CC 0
TC 5
pH 7.2
TA 100
CH 290
CYA 60
FC 5
CC 0
TC 5
pH 7.2
TA 100
CH 290
CYA 60
If you want to add borates in stages, you can. It is a little more work that way, and low borate levels won't be particularly effective at doing any of the things borates do, but you can spread it out if you want to.
The pool calculator suggests that I add Chlorine, which is understandable. The calculator also suggests that I raise the TA a bit by adding baking soda. But then it also shows that I need to add washing soda or borax to raise the pH. Which should I do? Can I add Boraxo since I was going to do that some day anyway to raise the pH and will this raise the TA also?
FC 3.5
CC 0
pH 7.2
TA 70
CH 280
CYA 80
Temp 88
FC 3.5
CC 0
pH 7.2
TA 70
CH 280
CYA 80
Temp 88
Hey, Fredo,
You're making good progress and understanding everything pretty well. That said, I would like for you to hold off on the borates until you get your pool water balanced a little better. You can always come back and add it later and it is an option, anyway....I have never done it and my water sparkles.
In this order, I would suggest the following....
1. drain about 20-25% more of your pool water to get down to around 60...almost perfect for a manually chlorinated pool.
2. Then, start keeping your FC between 5-7ppm.
3. Leave your pH alone and let it rise on up to around 7.4 - 7.6 or so and keep it there. Leave your TA alone for now.
4. Hold those levels for a few days or a week and then decide if you want to add borates.
You're making good progress and understanding everything pretty well. That said, I would like for you to hold off on the borates until you get your pool water balanced a little better. You can always come back and add it later and it is an option, anyway....I have never done it and my water sparkles.
In this order, I would suggest the following....
1. drain about 20-25% more of your pool water to get down to around 60...almost perfect for a manually chlorinated pool.
2. Then, start keeping your FC between 5-7ppm.
3. Leave your pH alone and let it rise on up to around 7.4 - 7.6 or so and keep it there. Leave your TA alone for now.
4. Hold those levels for a few days or a week and then decide if you want to add borates.
A test kit question I was wondering about:
I bought a Speedstir and a TF-100 test kit. In the test kit, there is a graduated cylinder for Chlorine test only and a separate cylinder for all other tests. I use the cylinder that came with the Speedstir for all tests including Chlorine. Is this a conflict?
I bought a Speedstir and a TF-100 test kit. In the test kit, there is a graduated cylinder for Chlorine test only and a separate cylinder for all other tests. I use the cylinder that came with the Speedstir for all tests including Chlorine. Is this a conflict?
We prefer to use the separate labeled Chlorine cylinder for chlorine because it tends to get black marks inside it, primarily above the 10 ml mark that is use for this test. That interferes with reading the tests that use 25 ml.
I too have the speedstir and use the single cylinder that came with it for all tests. I am pretty sure the tf-100 cylinders do not fit the speedstir correctly. Just make sure you rinse it numerous times between tests. Mine has not gotten a black line as anon mentioned, but if it did, I would probably not worry about it. I love the speedstir!
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