How do you handle consistent high bather loads?

[jareckik4]

I will be teaching swim lessons in my 10,000 gallon above ground pool. Over the course of 3-hours there will be 15-20 different individuals in the pool. This is true 4 consecutive days each week. I'm the only individual who will be in the pool for more than 10-20 minutes, if that changes bather load calculations.

I am brand new to pool ownership and I am trying to determine how to handle this situation. The pool store's suggestion of 1lb bag of shock each time there is a high bather load sounds like a fast track to wildly out of wack pool chemistry. I also don't like the idea of just throwing stuff in the pool without testing as there will be children in there. I've seen suggestions here to raise FC prior to a high bather load, but not seen exactly how much to raise it or for how long? Also, do I need to wait a certain amount of time after the pool is empty before testing and re-balancing? Should I test twice a day, before and after the high bather load?

I have ordered the TF-100 Test Kit and would love someone to explain this to me as if I am 5.

 

[Texas Splash]

I have ordered the TF-100 Test Kit

^^^ That right there! You hit the nail on the head. Just hang tight and stay tuned with us for more feedback. The pool store will not help with any of this unless you just want to empty your wallet. Once you get the test kit, post a full set of numbers for us. We'll coach you through the next steps. Once your water is balanced correctly, the focus for large groups is primarily to maintain a decent FC level. We do that "accurately" with the TF-100. The FC/CYA Levels and chart below will will help keep you straight. Also be sure to bookmark our Pool Care Basics for lots of great info. Welcome to TFP!

 

[Texas Splash]

In the meantime, be sure to update your signature details. See my signature as an example. If you are on a portable device, you may need to turn it sideways to see signatures at the bottom of each post. The article below should also help.

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[Newdude]

Bather load varies with the bather. Somebody sweaty or lathered up in sunscreen adds more residuals than someone who isn't. Kids add their own giant question mark with less than stellar bathroom breaks.

Swimming is safe between min and slam for your CYA. You'll have to road test it to see that you usually lose X FC per hour or group. Then make sure you stay free and clear away from min at the FC low point.




Did you notify your homeowners of a commercial pool ? It will change things drastically. One trip to the ER for a minor head bump will trigger health insurance dominos that can't be undone.

Say, Blue Cross goes after State Farm behind the scenes to cover the ER visit, but State Farm says you aren't covered as a commercial facility.

Regardless of how well everybody gets along or looks out for one another, if a health insurer or homeowners company gets involved, you could end up in court. And they have way better lawyers than you wish to pay for.

The town needs to be involved also to ensure public pool codes are followed. They likely won't align with TFPC.

 

[DrewLG]

I've seen suggestions here to raise FC prior to a high bather load, but not seen exactly how much to raise it or for how long? Also, do I need to wait a certain amount of time after the pool is empty before testing and re-balancing? Should I test twice a day, before and after the high bather load?

For a pool, a rule of thumb is one ounce of 12.5% bleach per bather-hour. (For a 100F hot tub, it's two ounces.) That's assuming that no one pees in the pool; a cup of urine can drop FC by 1ppm.

Remember that "high" FC isn't uncomfortable or dangerous so long as the FC concentration is below 40% of the CYA concentration -- so if you typically keep your FC at around 10% of your CYA, you could easily double the FC level with no negative consequences.

Testing before and after is a good idea. You'll quickly learn what's actually needed for your situation.

Before you test, you should wait at least 15 minutes after adding chemicals, and probably an hour or two after the last bather leaves the pool.

 

[jareckik4]

per bather-hour

Could you please let me know how to calculate bather-hours? If in 1 hour, I am in the pool the whole hour and there are 6 other people in the pool for 10 minutes each. Is that 7 bather-hours or 2 bather-hours or something in between?

 

[reggiehammond]

Did you notify your homeowners of a commercial pool ? It will change things drastically. One trip to the ER for a minor head bump will trigger health insurance dominos that can't be undone.

Say, Blue Cross goes after State Farm behind the scenes to cover the ER visit, but State Farm says you aren't covered as a commercial facility.

Regardless of how well everybody gets along or looks out for one another, if a health insurer or homeowners company gets involved, you could end up in court. And they have way better lawyers than you wish to pay for.

The town needs to be involved also to ensure public pool codes are followed. They likely won't align with TFPC.

Sage advice both from the local codes perspective, but also on insurance.

 

[DrewLG]

Could you please let me know how to calculate bather-hours? If in 1 hour, I am in the pool the whole hour and there are 6 other people in the pool for 10 minutes each. Is that 7 bather-hours or 2 bather-hours or something in between?

Mathematically it's exactly 2, but for this purpose I'd treat it as more, because your FC will be oxidizing the initial layer of contaminants from seven people.

But it doesn't really matter, because you don't have to be precise if you have a reasonable level of CYA in the pool. Even if you added a full quart of 12.5% liquid chlorine -- as though you were compensating for 30+ bather-hours -- you'd only raise the FC concentration by 3ppm. And that won't affect the swimmers or equipment in any negative way.