Cyanuric Acid

SteelBlue

Active member
Jul 4, 2019
40
Scottsdale, AZ
So I'm into my second month after having pool resurfaced. I'm doing my own chemicals now, using the info I've gained here. I have a 50 pound bucket of TriClor and rather than add CYA to the recommended amount, I'm wanting to use these tabs up and let the CYA build up gradually, or at least until the bucket is empty. I've been able to maintain reasonable FC levels using them and testing daily. My plan would be to switch to liquid chlorine once these are gone, and then add any more CYA as necessary. Is there anything wrong or detrimental to this approach?
 

mguzzy

Well-known member
Jul 8, 2015
649
OV, CA
Can you tell us what your CYA level is? If you use the pool math app you can see how many pucks it will take to raise your CYA level to where you want it.. Sounds like it might take awhile. But I'm guessing without knowing what your numbers are.
 

SteelBlue

Active member
Jul 4, 2019
40
Scottsdale, AZ
Using the Taylor kit where you watch the black dot slowly disappear in a cloudy solution, I would estimate my CYA levels are around 15. The kit only measures to a low of 20, but the dot is close to gone at the 20 mark, so I'd say 15. The Pool Math app allows you to select either dry or liquid CYA, so I'm not sure how to calculate the amount of pucks. Bottom line is I want to get rid of the pucks to maintain proper FC levels, and then calculate the amount of CYA I need to add when I switch to liquid chlorine.
 
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mguzzy

Well-known member
Jul 8, 2015
649
OV, CA
Actually the rule of thumb is you round up.. there really is no difference between 15 and 20. What kind of equipment do you have? I'm guessing you don't have a SWG if you are going to switch to liquid CL. You want to follow this chart, FC/CYA Chart .. If you follow the Math app it will tell you how many tablets it will take to get you there. I would tend to suggest you switch to liquid chlorine now and save your pucks for when you need to let the pool self chlorinate when you are away.
 

SteelBlue

Active member
Jul 4, 2019
40
Scottsdale, AZ
Tested my CYA level today and it was 50, so it looks like I've reached my goal and then some with pucks. I removed my floaters. FC was 5 and I added 1 qt.10% bleach to bring my FC up slightly from the existing level of 5. CYA/FC chart says the FC should be 6-8.
 

mguzzy

Well-known member
Jul 8, 2015
649
OV, CA
Sounds like you got it dialed in.. CYA does slowly breakdown over time so test it every now and then to see what the rate of decrease is in your pool. Happy swimming.
 

SteelBlue

Active member
Jul 4, 2019
40
Scottsdale, AZ
So I've had two days of using liquid bleach (10%) with adequate CYA levels, and if these two days represent what the future will be like, I'm needing to add bleach daily to keep the FC in range (6-8). Does that sound typical or normal to you guys? I'm not complaining because it's easy to do, I just thought perhaps the CYA would stabilize the FC for more than a day at a time.
 

IceShadow

Gold Supporter
Jun 8, 2019
1,061
Milwaukee, WI
With CYA at proper levels for your clime it’s standard to lose 2-4ppm FC per day to the sun. Daily addition is standard for TFP care.