FC Level for My Saltwater pool

[Newbiepoolowner11]

Hi all,
I’m pretty new to owning a pool. As I was reading this forum (a lof of useful information), one thing I don’t understand is the FC for salt water. I’ve seen some post above suggesting to leave FC at 6 or 8. I thought it’s not safe to swim at level higher than 5? Please excuse my lack of understanding.

 

[mknauss]

Welcome to the forum!
FC level is dependent on your CYA level in the pool water. See FC/CYA Levels
You can safely swim in a pool as long as the FC is above the minimum and at or below SLAM level based on your CYA. You must also be able to see the bottom of the pool in the deep end of the pool.
Read Free Chlorine - Further Reading
I suggest you read ABC's of Pool Water Chemistry.

 

[Newdude]

Welcome NPO !! You need your own threads for separate questions. There are many sub forums to get targeted answers from the pros who hang around their specialties.

Safe chlorine levels for both sanitizing and people fluctuate based on the CYA level of the pool. As the CYA increases, the level of chlorine needed does as well. SeeFC/CYA Levels. It is not well understood in the industry, or, *** most likely or***, they purposely ignore it to throw the pools out of whack to make the store more money.

 

[Newbiepoolowner11]

Thank you for the response and please excuse my ignorance. But my thought is why increase cya to 70-80 level and in return have to increase FC to high level to keep it effective. Why not do nothing with CYA or keep it low, mine is currently 30. I measured FC through out the day and I’m able to maintain at least 2.5 FC on a hot 100 degree day. Will it be sufficient?

 

[jimbethesda]

It’s a one time bump up of FC. Then your daily FC loss should be lower.

 

[Newbiepoolowner11]

Thanks Jim. Nice looking pool you got there. I guess if the SWG is able to keep up, won’t the preference be to not add any additional chemicals if you don’t have to.

Just trying to have a “clear” understanding, it’s a little “cloudy” at the moment.

 

[jimbethesda]

You can absolutely keep your CYA at 30. Your SWG is rated for a certain lifetime hours of producing chlorine. (50% for 8 hours = 4 hours producing). A higher CYA allows you to turn down the %, which in turn extends the life of the cell.

 

[tucsontico]

Welcome to TFP!

While every pool is different, if you look carefully at the FC/CYA chart, you'll note there are separate recommendations for an SWG pool and a non-SWG pool. The primary reason to maintain a higher CYA level in an SWG sanitized pool is to prevent the chlorine "burning off" from sunlight. SWG pools can have lower relative FC levels due to the higher concentration of chlorine in the SWG.

To get the longest life out of your SWG you shouldn't have to run it at 100% 24/7. Having a bit more CYA in the pool will allow the FC to remain available for sanitization while not "stressing" the SWG. I've run my SWG at 60% (on average) about 6-8 hours each day for the last 7 years. Even though my SWG is near the end of it's life cycle, my pool has never had an algae issue and I can maintain 3-4 ppm FC with CYA at 70. BTW, my pool gets 12+ hours of full sun here in AZ.

 

[Newbiepoolowner11]

Thanks! It’s good to see what another pool owner is doing. Previously I’m able to maintain 3-4 FC with SWG running at 30% and pump running 8 hours a day. Recently I have family over with 7 kids swimming every day so I bump it to 75%. It seems to be able to keep up for now. However I do have the pump running 24/7 just for same measure while they are staying for the week.

The only challenge seems to be having to put in 10 Fl Muratic Acid every day or every other day. Seems like a bit much?

 

[Timujin]

If there was only a way to have a MA generator.

 

[Donldson]

The only challenge seems to be having to put in 10 Fl Muratic Acid every day or every other day. Seems like a bit much?

What is your TA level?

 

[Newbiepoolowner11]

Hi Donldson,

my TA is currently at 80 and CH at 230.

 

[Donldson]

Let that drop down to 60 and see if that helps. SWG pools usually need a lower TA to help keep the pH more stable.

 

[Newbiepoolowner11]

Awesome thanks for the tip. It was at 60 previously but pool store got me to spend $20 on 5lb of baking soda. That was before I knew any better.

 

[mguzzy]

Hi NBPO...
As you play with the chem levels for your pool you will find a happy medium. For me a CYA of 60-70 and a FC of 7ish seems good, the pH hovers around 7.8 and I really don't worry too much about my TA, since it acts a buffer for the whole system.. it finds its own equilibrium with the pH. If you experiment with your CYA levels I think you will find there is a point where there is much better FC retention and a particular CYA.. it varies with each pool.. these guidelines are a rough idea to get you in the right range, and you can fine tune it from there.
Happy Splashing!