some basic questions.

[elik]

Hi to all.

i have just started taking care of a 40,000 liter pool, with a SWG and pH controller.
after reading through the very helpfull pool school for a while, i still couldnt find an answer for these following questions.

first of all- the chlorine solid tablets, do they contain CYA?

Is it dangerous for the pH controller to be on when pepole are swimming in the pool?

I keep on adding salt, and the SWG keeps telling me to add some more, there are about 70 people swimming in the pool per day, and it is outdoors, i assume those details are connected, but how much approx KG salt would the SWG need? it is set to 100% which i couldn't realize exactly of what.

the pool has a sand filter, how often should it be backwashed?

Id really appreciate your help.

 

[linen]

Welcome to tfp, elik

first of all- the chlorine solid tablets, do they contain CYA?

Most likely yes...(there are few pucks made of calhypo, but that is rare). Look at the active ingredient...if it has something including "trichloro" in the name...they have cya.

Is it dangerous for the pH controller to be on when pepole are swimming in the pool?

I wouldn't think so, but I do not have one...so hopefully others will chime in.

I keep on adding salt, and the SWG keeps telling me to add some more, there are about 70 people swimming in the pool per day, and it is outdoors, i assume those details are connected, but how much approx KG salt would the SWG need? it is set to 100% which i couldn't realize exactly of what.

How much are you adding daily? Splashout (could be a lot in your high usage pool situation), leaks and overflow are the only things that cause salt levels to decrease....the salt is not "used up". 100% setting probably refers to the swg producing chlorine the whole time it is set for, verses say 50% where the swg is cycling on and off.

the pool has a sand filter, how often should it be backwashed?

Our recommendation is to backwash when the filter pressure goes up 25% from the clean filter pressure.

there are about 70 people swimming in the pool per day,

That is a very high usage pool. Are you having problems maintaining clear water?

 

[elik]

Why wouldn't the salt be used up the same way chlorine would? from what i understood all the SWG does is cause NaCl react to Na+ and Cl-...i have added about 3 Kg over the last five days.
The water definitely isn't clear, but i don't think that its possible to be clear in such a condition, as long as the results are normal i am satisfied...

Thank you so much for all this help!

 

[Richard320]

Why wouldn't the salt be used up the same way chlorine would? from what i understood all the SWG does is cause NaCl react to Na+ and Cl-...i have added about 3 Kg over the last five days.
The water definitely isn't clear, but i don't think that its possible to be clear in such a condition, as long as the results are normal i am satisfied...

Thank you so much for all this help!

http://www.troublefreepool.com/post4367.html#p4367

Scroll down a couple posts and chemgeek has the chemical equations and explanations for a SWG

 

[elik]

I read some of it and it was helpful, but i still have on unanswered question: hoe much salt would the SWG approx need? it is constantly telling me to add salt, ive added about 3Kg, and i am scared of adding to much, it is a 40,000 liter pool...

 

[Richard320]

I read some of it and it was helpful, but i still have on unanswered question: hoe much salt would the SWG approx need? it is constantly telling me to add salt, ive added about 3Kg, and i am scared of adding to much, it is a 40,000 liter pool...

Pool Calculator can do the math - there's even an option to use that fiendish metric system up at the top right. 3 Kg salt will only raise it by 75 ppm.

 

[elik]

Very cool...however, im i assume i am aiming at 3000ppm, or does it change from one SWG to the other?
also, i converted 1Kg to 33oz, is there any better way?

 

[Richard320]

Very cool...however, im i assume i am aiming at 3000ppm, or does it change from one SWG to the other?
also, i converted 1Kg to 33oz, is there any better way?

Where are you? You give the pool in liters, which leads me to believe you're not in the US. Why do you want ounces? http://www.poolcalculator.com/ will work in US or metric, just choose the units.

You should have a manual for that SWG which will give you a preferred range. If you don't have the manual, post what brand and model it is and maybe someone else can help.

Fill out location and equipment, please. Directions to do that are in pool-school/read_before_you_post

 

[elik]

As you can see i added some info to my signature and profile, and the SWG is Aquablue model 5, if anyone can give a ling for the manual it would be very helpful.

 

[Richard320]

Look at this manual and see if it looks like yours: http://solaxx.com/files/AquaBlue_Manual.pdf

If so, target salt is 3500