New to Forum CYA question

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akaistha

Member
Aug 4, 2014
12
Coppell, TX
Hello,
I wanted to start by thanking folks who have put so much useful information for novices on this website. This sit might have helped me keep my sanity too. 3 weeks ago I had algae in the pool with zero ability to raise Cl using shock or the tabs. However some elbow grease (repeated cleaning of the cartridges) and following BBB including shocking with bleach I seem to have a very clean pool.

I have a question regarding the water chemistry. Measurement done using Taylor K2006 test kits.

FC: 5ppm
CC <0.5ppm.
ph: 7.4 (lower than 7.6)
CYA: 120 using dilution method. Thanks pool stores !!!
TA: 90 (<100).
Location: Dallas, TX
Pool Pressure OK (cleaned it 5 days ago).
Scrub pool every day.
Pool Volume @18000 gallons. I will do the testing for others chemicals tomorrow.

The pool looks very clean. I have no algae or cloudiness-the concern I have is with the CYA so high and both FC and CC holding up-do I need to worry about water sanitation? I add 2 cups of bleach in the morning and evening to maintain the Cl levels. I am little concerned about raising the Cl higher as I have young boys who are learning to swim and may/do ingest little water.

I recently switched to BBB-promised to myself that I will never go to Leslie's pool.

Thanks in advance for your inputs.

Amit
 
Welcome to TFP!

You need to maintain a higher FC level due to the CYA level to keep the pool safe. You should be keeping it above 8ppm at all times ... it is perfectly safe and lower active chlorine levels than you would find in an unstabilized public pool.

Remember the pH test reads higher than reality when the FC is greater than 10ppm. This is one problem with keeping the CYA too high.
 
Thanks Jason. Will do so.

Per the pool calculator- I need to add 96 oz of 8.25% bleach to increase the FC from 5ppm to target of 8ppm (minimum). I will then do the FC loss test during the course of the day and also overnight. Hopefully this will provide me with the correct amount of chlorine to add everyday.

BTW do I need to shock my pool again if I am able to maintain FC to 8ppm MIN?





jblizzle said:
Welcome to TFP!

You need to maintain a higher FC level due to the CYA level to keep the pool safe. You should be keeping it above 8ppm at all times ... it is perfectly safe and lower active chlorine levels than you would find in an unstabilized public pool.

Remember the pH test reads higher than reality when the FC is greater than 10ppm. This is one problem with keeping the CYA too high.
Click to expand...
 
akaistha said:
Thanks Jason. Will do so.

Per the pool calculator- I need to add 96 oz of 8.25% bleach to increase the FC from 5ppm to target of 8ppm (minimum). I will then do the FC loss test during the course of the day and also overnight. Hopefully this will provide me with the correct amount of chlorine to add everyday.

BTW do I need to shock my pool again if I am able to maintain FC to 8ppm MIN?
Click to expand...
If you pass the overnight loss test, you don't need to SLAM again. Poolmath says your target should be about 12, and the minimum FC is 9. So if you raise it to 12 and retest it at roughly the same time tomorrow and it's above 9 , 12 is your target. If it comes up at 8 or 8.5, target 13. You'll know soon enough what the pool's appetite is.

One caution: when FC is above 10, the pH test starts reading strange and you can't trust it. If you have the ability - water rationing or whatever - you would do well to lower the CYA. You won't really use more or less bleach every day either way, but it's really nice to be able to trust the pH readings. It doesn't have to be all at once; you can drain out a few inches at a time to water the lawn. If you close the pool for the winter and drain down, just deal with it then.
 
Richard320 said:
If you pass the overnight loss test, you don't need to SLAM again. Poolmath says your target should be about 12, and the minimum FC is 9. So if you raise it to 12 and retest it at roughly the same time tomorrow and it's above 9 , 12 is your target. If it comes up at 8 or 8.5, target 13. You'll know soon enough what the pool's appetite is.

One caution: when FC is above 10, the pH test starts reading strange and you can't trust it. If you have the ability - water rationing or whatever - you would do well to lower the CYA. You won't really use more or less bleach every day either way, but it's really nice to be able to trust the pH readings. It doesn't have to be all at once; you can drain out a few inches at a time to water the lawn. If you close the pool for the winter and drain down, just deal with it then.
Click to expand...

Thanks Richard- overnight FC drop was about 2.5ppm. I had tested at 5ppm at about 7:00 PM and retested to 2.5ppm today AM. I have added more bleach to increase the FC to 7 ppm and will see how much FC is lost during the day.
 
jblizzle said:
You failed the OCLT. Are you gong to start the SLAM process? Your FC is much too low.
Click to expand...

Yes Jason. Tonight I will start the SLAM process. Based on the numbers from pool calculator and the CYA/FC relationship I will add 850oz to get to 39ppm shock value assuming a start FC of 7ppm. I will let it run overnight and then do the OCLT test. I will then maintain the FC to 12-13ppm range. I understand that the best way forward will be to get CYA down via pool drain but I am planning to do that during the winters (will also convert the pool to salt water...). I will post the results here.
 
Given you need to replace a little less than 9000 gallons of water, I highly suggest you do this first. If you can get in the 70-80 range, you will be a lot better off for the SLAM process, and it will put you in the proper range for your salt system.
 
Sounds like you're planning to end your slam prematurely. To end the slam you need to pass all three criteria.
1. Pass the OCLT < 1ppm fc loss overnight.
2. Less than .5ppm CC test
3. clear water with no visible algae
If you don't, you must I keep your FC up to shock level.
 

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