How often to replenish chlorine

[kawisser]

Those of you that manually chlorinate with liquid chlorine...

How do you decide how soon to replenish your chlorine? Let's say I'm targeting 7. Do you start at 9 and replenish when it gets to 5, averaging 7? There must be some degree of overshooting and undershooting or else you'd be replenishing a tiny bit every few hours and I doubt anyone does that. What's the method here?

 

[TheSteamingPile]

Don't let FC drop below the minimum level and it doesn't really matter how wildly it swings.

 

[an1vrsy]

Based upon accurate self testing, I had determined my pool lost 4 ppm FC every day. Then I’d add 4 ppm chlorine every day. When I did manually dose, it was after I got home from work, so late afternoon. What I added the day before got me to today. If targeting 7, I added to 11.

When I moved to Las Vegas and built my pool here, I made sure I included a SWG. So, now I set the SWG to add 4 ppm every day.

 

[PoolStored]

How do you decide how soon to replenish your chlorine? Let's say I'm targeting 7. Do you start at 9 and replenish when it gets to 5, averaging 7? There must be some degree of overshooting and undershooting or else you'd be replenishing a tiny bit every few hours and I doubt anyone does that. What's the method here?

Looking at your logs, your FC is very low for your CYA. Your CYA is 60 (round up). Your minimum is 5 and target range is 7-9. Get some chlorine in there POST HASTE. 2s and 3s is way too low.

In Indy, this time of year, you are likely using about 3-4FC daily. 2-3 if you have a solar cover. I am losing 3FC in northern Ohio without cover, 2FC with cover. I would target the top end of the range until you know what your pool uses. Target 9-10. What that means in practice....

Choose a time of day you are going to test and replace. Test. Add enough LC to get to 10. Wait a day and test again. That will give you your general FC loss. Keep your target high enough so that your loss does not get to 5. If your loss is 4, then target 10FC on replacement...then your FC will not get below 6. Make sense?

FC loss will vary by month/bi-weekly. I lose 1.5-2 in April/May, 3-4 in June/July, 2-3 in August, 1.5-2 in Sept/Oct. This certainly depends on your CYA level, but you will learn how much FC your pool loses with varying CYA.

 

[proavia]

How are you testing?
A good number of your results look like they came from pool store testing.
With a K-2005 test kit, it's not possible to get some of the results you posted.
You still need the FAS-DPD (K-1515) test kit to accurately test FC and CC.

Why are you using PhosFree?

 

[kawisser]

How are you testing?
A good number of your results look like they came from pool store testing.
With a K-2005 test kit, it's not possible to get some of the results you posted.
You still need the FAS-DPD (K-1515) test kit to accurately test FC and CC.

Why are you using PhosFree?

I have a K2005 kit but I added the FAS-DPD shortly after I bought the kit. I use the FAS-DPD for chlorine testing. I do still go to the pool store maybe once a week or so to validate my numbers and, as you mentioned, pick up Phosfree and other (free for now) chemicals like liquid chlorine. I'm still on the builder's dime and he wanted me to get my phosphates down. It started at 4500 and his goal was to get it below 500. I figured since he's paying for it still, it was a legit concern, no? I currently measure about 700 on phosphates.

 

[proavia]

Trying to "validate" your results by comparing to the pool store is a waste of time. Pool store results are rarely accurate or repeatable. Use your test kit and post only those results here. Believe in your testing.
Add the K-1515 to your signature.

PhosFree is a watered down phosphate remover and a high profit magic potion for pool stores.
If you properly chlorine your pool (FC/CYA Levels), phosphates are of no concern.
Any phosphates the PhosFree removes can clog your filter. Be prepated to clean the filter more frequently.

 

[kawisser]

Trying to "validate" your results by comparing to the pool store is a waste of time. Pool store results are rarely accurate or repeatable. Use your test kit and post only those results here. Believe in your testing.
Add the K-1515 to your signature.

PhosFree is a watered down phosphate remover and a high profit magic potion for pool stores.
If you properly chlorine your pool (FC/CYA Levels), phosphates are of no concern.
Any phosphates the PhosFree removes can clog your filter. Be prepated to clean the filter more frequently.

Thanks for calling that out. The pool builder gave me a set of "loaner" filters to use while using phosfree because he said it would get my good filters very dirty. So far I still have my good ones waiting to put them back in. I'll remember to NOT use phosfree anymore, and especially not after I put the good filters back.

 

[cledee]

Those of you that manually chlorinate with liquid chlorine...

How do you decide how soon to replenish your chlorine? Let's say I'm targeting 7. Do you start at 9 and replenish when it gets to 5, averaging 7? There must be some degree of overshooting and undershooting or else you'd be replenishing a tiny bit every few hours and I doubt anyone does that. What's the method here?

I target to get a little on the higher side so if I had CYA of 60 I would be adding enough to get back to 10 or a little higher than 10. Then once it drops to 7 or 6, I would add enough to get back to that 10+ range.

 

[kawisser]

I target to get a little on the higher side so if I had CYA of 60 I would be adding enough to get back to 10 or a little higher than 10. Then once it drops to 7 or 6, I would add enough to get back to that 10+ range.

I can already feel the backlash I'm about to get, but I need to ask anyways... 10 isn't too high? There are lots of websites online that say 10 isn't safe to swim in.

 

[PoolStored]

See first graph here...%HOCl based on FC and CYA. 10FC with a CYA of 30 is less harsh than .8FC with a CYA of 0.

Pool Water Chemistry

This thread presents my findings so far on pool water chemistry including the following: More Accurate Calcite Saturation Index (CSI) to replace Langelier Saturation Index (LSI) Calculation of ppm HOCl (disinfecting chlorine) at various levels of Total Free Chlorine (FC) and Cyanuric Acid (CYA)...

www.troublefreepool.com

 

[cledee]

I can already feel the backlash I'm about to get, but I need to ask anyways... 10 isn't too high? There are lots of websites online that say 10 isn't safe to swim in.

A lot of the websites don't take into consideration the relationship between CYA/Chlorine. 10 for a lot of those websites are what they call "Shock levels".

The more CYA you have in your pool, the more FC stays in reserve, that means that at a given time only around 1 to 2ppm of FC are available to sanitize and protect you, and the rest is bound and in reserve. As FC is used up, more is released from reserve. So, having 10 FC with a CYA of 60 is not as harsh as it sounds.

That's why CYA is important that you need at least 30ppm but not more than 60 for non-swg pool otherwise it would be hard to maintain if you got algae.