High Free Chlorine (FC): Over 30

[water0125]

I've been maintaining my pool for about 3 months. Just came out from a leak situation and am now trying to get everything balanced.

I've tested my FC a few times and keep getting over 12.

What do I need to do?? Thanks!

 

[Rancho Cost-a-Lotta]

What's your CYA level?

What test kit are you using?

 

[mknauss]

Your Poolmath shows a 40 ppm CYA. A bit low for a SWCG. If you wish to have the FC come down some, lower the generation of chlorine by the SWCG.

 

[Rancho Cost-a-Lotta]

What's your CYA level?

What test kit are you using?

My bad. Forgot to check your logs.

 

[water0125]

Using the tfp test kit. The fanciest one. lol

I’ve looked at my SWCG previously. All of the lights were lit up. Not all the time though.

When I pressed the buttons that were supposed to adjust the output, none of the lights changed.

Is this something that I would adjust from the panel instead? Thank you!

 

[water0125]

For the cya, I’m in DFW. My pool is 75% shaded all day. What would be the preferred CYA?

 

[jark87]

Here’s a link that will give you the recommended levels.

The Free Chlorine and Cyanuric Acid Relationship

Managing your cyanuric acid and Free Chlorine levels is key to stabilizing your pool. Learn how these two items affect each other.

www.troublefreepool.com

I’m also in DFW and keep FC in the 8-10 range, with CYA at 80ish. (I can never tell for sure what the CYA level is. )

 

[Texas Splash]

What would be the preferred CYA?

We recommend 70 in our TX summer. Since you seem to receive a lot of shade on the water, I would at least take the CYA up to 60 and go from there.

 

[water0125]

Since there is another Texan on this thread, I’d love your input on calcium hardness. The Pool Math calculator shows target of 450, but in the threads I am seeing suggestions of 250. What should I aim for?

Ps: maybe this test is not affected by location. If that’s the case, please correct me.

 

[reggiehammond]

Enable CSI tracking in PoolMath and let it guide you to proper pH and CH levels. You need to watch CSI to avoid scaling in your SWCG; you want to be 0 to -.6 as much as possible.

My pool is full sun; I have to have CYA 70-80 or my FC can't keep up. Your pool is different.
From your logs, it appears you're getting some bad pool store / pool guy advice. Avoid that...

 

[water0125]

Thanks for the tip on enabling CSI. I hadn’t seen those options. My CSI is -0.45.

The app says to avoid a value of less than -0.3 for extended periods, so I think that I need to bring it up, right?

 

[water0125]

I also just went out to my pool. Full sun covers about 75% of the pool for a few hours. I’ll start watching that more closely.

 

[reggiehammond]

Thanks for the tip on enabling CSI. I hadn’t seen those options. My CSI is -0.45.

The app says to avoid a value of less than -0.3 for extended periods, so I think that I need to bring it up, right?

No - I'd stay right you are as you're still in the ok range. Any fill water you add will increase your TA slightly, which will raise pH and CSI.

What % is your IC40 producing? One benefit to increasing CYA is increased FC durability. This would allow your SWCG to run less, lengthening its useful life.

 

[water0125]

Ok! Won’t add any more calcium hardness then.

Scrolled through my panel and found the intellichlor. It showed 50% for pool and 0% for spa. Since my FC was high, I reduced to 45%. Not sure how much I should reduce to get my FC in the right range. Reducing by 5% seemed like a small change, but I also didn’t want to swing the other way.

 

[water0125]

Added 2lbs of powdered CYA. I've only used the liquid so far, so this is my first time using powder. Bought it at Leslies and put it in a filter sock and hung it in the skimmer. Backwashed my DE filter, before I did it, since it was about time. Gonna check my FC later today to see if reducing the Intellichlor percent on my panel made any difference. Fingers crossed!

 

[water0125]

Gah! My FC is crazy high at 15!!! I’ve lowered the intellichlor from 45% to 35% now. Could increasing the CYA make the FC higher? Or appear higher because it’s not being consumed as quickly now?

 

[reggiehammond]

Yes - higher CYA provides more protection for the FC (which is desirable!)
But higher CYA requires a higher FC level, so you don't want to adjust too much.

FC 15 is not an issue. Not something to worry about or think that it's "high" or dangerous. Lowering the SWCG slowly and watching results is important; you don't want to over-react and then end up with algae due to lack of FC.

 

[water0125]

Good to know! I was feeling nervous. I wasn’t sure if it being high could be problematic. Pool math suggests 3-10ppm. What do you think would be a good level with a CYA of 70?

 

[proavia]

Good to know! I was feeling nervous. I wasn’t sure if it being high could be problematic. Pool math suggests 3-10ppm. What do you think would be a good level with a CYA of 70?

At CYA 70, probably 6 or 7 to 10.
This will allow for normal daily FC loss.
The minimum of 3 is just that minimum. Never fall below at the lowest FC of the day.
For a medium to large swim event, I'd dose to 15 prior to the party, possibly check/dose FC half way thu and dose again after the party.
The pool is safe to swim in as long as FC is between minimum and SLAM level- and you can see the entire bottom of the pool. For CYA 70, the SLAM Process FC level is 28.

 

[water0125]

Mind blowing info! I'm still wrapping my head around what levels can be high or lower than optimal and in what situations. There is so much to know!

Thanks for confirming that the FC can be higher. I wanted to swim yesterday and was scared, thinking that a high FC might be unsafe. Sounds like a LOW FC is a problem. But, FC can go higher than optimal -- up to a point -- depending on CYA.

Just reviewed the forum for discussions about parties and dosing up the FC. We've had this pool for 9 years and I never heard about dosing up the FC prior to a party.

Looks like I can use pool math to determine the amount of bleach or liquid chlorine to add before a party to help with FC. Or increase my SWCG. And, should maybe keep my pump running overnight. Yay for starting to synthesize all the info in my brain!!