questions about TC, CC, CYA range,

Kegman

Member
Jul 5, 2015
14
Central NJ
So last year I had, (still have but am refusing to use it this year) the frog mineral system. This will be my second year with the pool and I had nothing but problems with my pool chlorine levels last year. My FC and TC were a constant battle at zero too many times and had constant algae blooms.

I did read your pool school and I have a few questions. If I go to the household bleach route, this will not fade my liner faster because liquid bleach is nothing but chlorine anyway right?

I opened the pool today and have last year's test strips. (i read about your recommended tester, I know, i'm getting it) Last year's test strips use the terms free chlorine and total Chlorine. I read here that TC = CC + FC. I threw in 4 bags of shock into the pool and the FC spiked, but the CC remained in the zero area. Im not sure if that's good.

I can't grasp the concept of the FC and CC as your pool school describes. So the fact that the FC is high while the TC remained unchanged makes no sense to me, there should have been some kind of increase to the TC because there was an increase to FC. My test strips say anything below a 1 in TC is low and not "ok" which I assume you disagree with? Do you have a recommendation to a TC level?

My other levels were at the test strips recommendations of PH 7.2 and TA at 80. CYA was in the 30-50 range according to the strip. Your school and tips for beginners says that a xtreme amounts of direct sunlight on the pool means I should raise my CYA. I live in NJ and get full sun all day. Where should my CYA be to make adding chlorine affordable but not burn it off all day? Last year my CYA was measured at 50 and held there all season long. Leslies recommended I keep it at 50. I'll be going there tomorrow for a water test.

Can you explain what non chlorine shock does? when should I use it?

Thank you for your patience, I'm sure these answers are littered throughout the forums, but I'd rather not spend hours looking through them all.
 

ff702

Bronze Supporter
May 11, 2016
98
Las Vegas, NV
It is not surprising that if you are only adding chlorine to your pool once a week that you would be at zero the next weekend. Chlorine is constantly being consumed as it works to sanitize your water of all the particulates and other materials that enter the pool. Some pools consume multiple ppm of FC each day depending on a number of factors. Because of this, while you are getting familiar with your pool's needs, it is recommended that you test both the FC and Ph daily and add the required chemicals to reach the target. FC targets are 100% based upon your CYA level. If your CYA is, in fact 50, you should be maintaining a FC of 6-8ppm through daily chlorine additions. If you raise your CYA level beyond the 50 the daily target for your FC will also raise.

FC is the number with which you need to be concerned. CC of greater than 1ppm is an indication that your pool has some type of sanitation issue. Therefore, a CC of 0 is indeed good, while a TC number of less than 1 would not be good because that number includes the FC that you need to sanitize. That said, TC is the sum total of both FC & CC.

Test strips will not be able to provide you with accurate information in order to take control of your water chemistry. Pool store tests are not reliable, lead to costly sales pitches for items you don't need in most cases, and are quite frankly way less convenient that having your own good test kit.

You mentioned that you will be getting one of the test kits recommended on this forum. I highly suggest the TF-100. Regardless of which you purchase, I wouldn't go without the addition of a SpeedStir.

I hope I hit all of your questions and was able to aid in your understanding.
 

Jezza

LifeTime Supporter
TFP Guide
Jan 18, 2015
990
Bunbury, WA, Australia
ff702 has got you heading in the right direction. Test strips are useless and will just have you getting frustrated with inconsistent readings.

Yes- liquid chlorine and bleach are both sodium hypochlorite. Liquid chlorine is usually sold as 12.5% and bleach 6-8%- you just need more bleach to have the same effect. It really comes down to whatever is cheaper or more accessible.

Essentially your FC is the chlorine that is available to breakdown organics and the CC is the used portion of chlorine which then is broken down further.

We don't necessarily suggest a one time shocking of the pool rather a process of SLAMming which is about maintaining a high level of chlorine for a sustained period of time.

It is worth reading the the ABC's of Pool Water Chemistry.