Safe to swim FC levels...

[lsbarkley]

Hi...just shocked my pool last evening to finally rid myself of algae (mustard?). Was at 24 FC and now at 19FC this morning. What level will it be safe to go back in the water. Thanks. Tried to search on this forum but couldnt find this info.

Ls

 

[JasonLion]

Assuming you have any plausible amount of CYA in the water, all outdoor pools should, then yes it is safe to swim. At higher FC levels I recommend a shower after getting out.

 

[lsbarkley]

Thanks for the quick reply. I will keep close track of it and let you know how its going. Thanks for your help immensely.

Ls

 

[mbar]

If your free chlorine dropped 6 ppms overnight, then you need to keep the chlorine at 25ppms till it holds. If you let it drop now, you will probably see the algae come back - especially mustard algae. You didn't post your cya, check out Chem geek's best guess table, and it gives you numbers for dealing with mustard algae.

 

[The Mermaid Queen]

Ls,

Shocking the pool is not a one-time deal... You need to test frequently (2-3 times a day if possible) and boost the FC back up to shock level (I assume 25 per your numbers given) until three things occur:

1. the FC holds steady overnight
2. you have no cc's
3. the water is sparkling

Many people are misled by the pool stores who tell them to "shock once a week." Personally, I think this method makes everybody feel good, but in reality does little or nothing for the sanitation of your water!!

 

[Guest]

i always shock thursday evening, are you saying i should shock more or less, or what should i change

 

[MikeInTN]

i always shock thursday evening, are you saying i should shock more or less, or what should i change

You should only shock when your CC gets to or above 0.5 ppm and doesn't drop, if you notice your FC dropping drastically or dropping overnight, or if you suspect you're getting algae (water looks dull, getting a green tinge, liner feels slimy, etc). Shocking once a week "just to shock" doesn't really accomplish much, I don't think. For example, I only shock my pool when I meet the criteria above, and have had to shock the pool maybe twice the entire season.

 

[mbar]

And shocking goes hand in hand with your cya level - if you mean you use one bag of shock per week, then you are only taking it up about 6ppms per 10,000 gallons of water. So one of the ost important numbers to know is your cya. You also hae to watch your calcium levels if you use the calhypo shock.

 

[lsbarkley]

Okay...I think I am going to shock again. Last night I raised the FC to 24. This morning FC was 19. I left the pump to run all day with the SWG being off since before shocking last night. At 7pm tonight FC was 6.5. So based on that I believe I need to shock again.

So tomorrow morning I am looking for the FC to be right at or around 24 correct? If it does hold how long does it take to come down to "normal" levels? Am I correct to leave the SWG off so I can tell how my shock is affected?

Thanks for the continued support!

Ls

 

[lsbarkley]

oh forgot to put my numbers down.

FC 6.5
CC 0
TC 6.5

ph 7.2
Alk 110
Cya 40

 

[mbar]

Yes, I would turn off the swg, and shock it back up to 25. If you lost that much chlorine in one day, you are still battling the algae Test in the morning, and if you use up more than 2ppms of chlorine, you will have to take the chlorine up to 25 again. The more you take the pool back up to shock, the faster the algae will all be dead 8) Then you can let the chlorine drop down to 5ppms. With a cya of 40, your target chlorine level is 5

 

[lsbarkley]

Okay thanks. Just poured in the bleach. Generally how long does it take to go down to 5? A day or two? What would you consider a FC level to be that would be okay to go back in the water (assuming no sharks!)?

 

[The Mermaid Queen]

I would not hesitate to get into a pool with 15 or even higher FC, with a CYA of 40, as long as the water is clear and no cc's, and FC holding overnight. Wear an old suit and rinse off when you get out, and don't drink the water!! (I would not let small children swim in a high-FC pool since they have a tendancy to drink the pool no matter what you tell them!!)

 

[Guest]

when i shocked i used 4 bags, put in a bucket full of pool water and one bag at a time, but thanks for the tip i will know that from now, should also save me some money.

 

[lsbarkley]

Update.....this morning my FC is now 19.5 .... I guess that means I need to reshock back up to 24.....to HE#L with that stinking mustard algae!

Water has been clear from top but only way to know is to jump in and see with goggles. It has definately cleared up 90% as of last night. I can see the drain and light from the shallow end pretty clearly...before I had to get about 6 feet away to see the small bottom drain. Its getting there. Thanks.

Ls

 

[mbar]

Yes, make sure you shock back up to 25. The ore consistant you are with keep the chlorine high, the faster the algae will all be killed. 8)

Just a note - I have gone swimming in my pool at levels of 25ppms, and my cya at 40. I didn't even get any fading of swimming suits . The only thing I did notice is that my skin got a little dry .