test results

[gregs]

Hi,
I took a water sample to the pool store yesterday because I wanted to check my CYA levels. I haven't mastered the disappearing black dot yet. My pool is 2 years old, full sun, approx 17,000 gals, plaster with a SWCG and haven't had any problems this year. Here are there results.

FC 3.0 PH 7.4 TA 55 CH 445 CYA 25 TDS 4900 92 degrees

I knew my CYA was going to be low after TS Debby dumped a lot of water on us and the pool overflows were running for a couple of days. It took one 40# bag of salt to get the level back up and operational for the SWCG.

My concern came from the high CH level as I thought this would have dropped after all the rainfall. Previously they had reported levels of 375 before the rain. I have a Lamotte test kit and double checked the CH myself and it appears to be closer to 350. So it made me question the other results so I ran my tests and these are the results:

FC 2.5 PH 7.5 TA ? my scale ends at 60 and it was less than that CH 350 CYA ? also less than the scale reads

Should I be concerned about the CH levels? I have checked the SWCG cell and don't see any scale or build up on the plates and the water line tile also looks fine.

Also my chlorine levels have been steady around the 2-3 range and I check adjust my pH at least weekly and add between a pint to a quart of acid once a week. The pool has been almost maintenance free this year other than brushing it and dosing it with acid. I did add a couple of gallons of bleach to it after the big rain figuring it would be best to keep the chlorine level up and not have to wait for the SWCG to do it.

Any concerns with the levels? Thanks

 

[Bama Rambler]

Yep, I'd be concerned with the CYA if it's really that low. You need to get it up to about 70. Everything else looks ok. I'd disregard the pool store tests.

You did good by manually adding bleach. I'm gonna give you and atta-boy for that!

 

[gregs]

Thanks for the atta-boy. Will raising the CYA levels back up cause a demand on the chlorine use? I understand what it does and all of last year I kept it in the 70-80 range. I was just amazed that I have been maintaing a FC range of 2-3 with a low CYA level for the past month.

 

[Bama Rambler]

Raising your CYA level should actually lower your demand which in turn should allow you to lower the run time or percentage of the swg.

 

[gregs]

That is where I am confused. I read in "pool school / chlorine/cya chart" about CYA and this is what I found "Generally, the more stabilizer, the more chlorine you need to maintain its effectiveness".

 

[RobbieH]

The more you need in the pool, not the more you need to use. But, that is not relevant to your SWG pool. You keep your SWG pool around 4ppm at all times. The water is sanitized when it goes through the cell where it is superchlorinated.

pool-school/water_balance_saltwater_generator

 

[gregs]

I got my CYA level back up to 70 and now I hold a steady 5.0 FC. I took the water sample to the pool store again to double check my CYA and to see if my CH stayed the same since my test results showed it lower. Again there test showed the exact same result (CH 445) and they told me all the evils of it being this high. Is this something I should be concerned about? My test shows it closer to 350. Also my TA is still on the low side at 60 but my PH has been very steady for the last 6 months only needing about a quart of acid a week to drop it from 7.8 to 7.6.