Pool Parties drinking up my Chlorine

[harleysilo]

This year we've started having parties with 20+ people/kids. I've had the cl level at 4-6ppm and by the end of several hours (4-5) you can visually tell the water is dull, and upon testing chlorine is at 0-.5. I need to remedy this for tonight's pool party.

Tonight we will have again have 20-22 people.

Chlorine level is 4.5 with no CC's
PH 7.5
water temp 94
CYA 0

If i plan for 4 hours of swimming it would be nice to know what type of chlorine loss I should experience.

Taking a WAG i'd say i should start with doubling it to 10PPM which is shock level for my pool with no CYA.

I realize having no CYA is the issue, and it is zero because i have a auto pool cover which is always on unless swiming , for the first year i ran 70 CYA and chlorine would stay high forever cause of no sunlight and no debris other than what swimmer's deposited. So i'm dealing with overuse for water conditions with these parties.

If i don't raise CYA, do i just have to raise it before and possibly due an addition of bleach mid party? I don't want to do that in the pool where people will see LOL. I could dilute in 5 gallon bucket and poor in pump hidden from view (with it off as it is higher than pool). Could stick hose in there as well, then in min or two turn pool pump back on.

What do ya'll think?

 

[toofast]

Experts will join in ,but with no CYA be careful how high you run your Chlorine...CYA also acts as a buffer, making a HIGHER Chlorine content SAFE.

I would at least run at a 30 CYA - and keep your Chlorine in the upper range if not even close to shock before the parties.

 

[JasonLion]

You really really want to have some CYA in the water, even if only up to 20. FC at 4.5 with NO CYA will (slowly) damage hair and swimsuits. CYA will also dramatically cut down on the production of the more dangerous forms of CC, and help your chlorine levels survive the occasional periods when the cover is open. We recommend CYA at 20 for indoor pools.

 

[bridgman]

One more vote for getting a bit of CYA in there -- my hot tub is covered except when in use, so I run CYA between 20 and 30 ppm.

There are some rules of thumb for the amount of chlorine required per bather-hour in a hot tub, and you could probably figure out something similar for your pool just by looking at how much the FC drops during a party (seems like 4-5 ppm).

Since your CYA is likely to be at zero for this party I would figure out how much bleach I need to add for 2-3 ppm FC, then add a quarter of that every hour diluted in a bucket or two of water and poured in front of the return, keeping people away from the return for a few minutes while it mixes. Once you have CYA in you may be able to raise the FC level enough before the party that you don't need to add anything during.

When I have people using the hot tub for a while I add some diluted bleach midway through and just make a joke of it. After a while people will start reminding you that it's time for "a dose".

 

[loop_pea]

With no CYA in your water, your chlorine would be gone in 4-5 hours even if nobody swam.

I have an opaque pool cover too and when the pool cover is on, the chlorine stays in the water. I recently refilled my pool, and so started with no CYA again. Shocked to 10ppm, cover on and floats under it to clean them... Left it a few days and the chlorine was still in the water. Took the cover off and poof my chlorine was gone in a few hours.

I like to get at least 10ppm of CYA in the water before allowing anyone in because otherwise the chlorine feels so strong that I don't even want to put my arm in there to take a water sample!

I had 125 kids in my pool yesterday (not all at once). The total chlorine consumption is only about 7ppm for the whole day or or roughly 1ppm every two hours while the pool was in use, and some of that is probably being used up by sunlight as my CYA is still pretty low at the moment at 15. Swimmers don't use up as much chlorine as you think.

 

[duraleigh]

The sun is eating up your chlorine......the pool parties only add to the issue....but you know that.

0 CYA is not a good idea in an outdoor pool for any reason I can think of.....even with a cover you should have at least 30 if not more.