High Chlorine Usage in small pool

[Danylukburton]

Hi All,
I have a small intex easy set 10ft round which is 1,000 gallons. My 3 kids LOVE it and spend at least 2 hours each day in it. Temps have also been hot (mid 90s) and it's in sun for around 8-10 hours a day. Our Chlorine usage is high. I am now using liquid chlorine (12.5%) and have a CYA 50-60. I add about 12oz LQ per day based on testing. Water is beautiful and clear, so why am I using seemingly so much chlorine?
I came across an old post where an expert gave an a average chlorine usage formula:
One person-hour in a 20,000 gallon pool requires (1 person-hour)*(4 g/person-hour)*(1000 mg/g)/(75708 liters) = 0.053 ppm FC to oxidize the bather waste

So using this formula for my 1000 gallon pool ( 3785 liters) = 1 * 4 * 1000/3785 = 1.056ppm FC per hour per bather. So if I have 3 bathers in for 2 hrs I'm over 6ppm just to oxidize their load.

Does this sound right? Do small pools have a much higher chlorine usage rate?

Thanks for any help or advice!!

 

[magiteck]

Does this sound right? Do small pools have a much higher chlorine usage rate?

I’m not an expert, but it would make sense to me that they do. Each bather is theoretically going to introduce a fixed amount of organics regardless of the size of the pool. In less water, less dilution would occur so the water overall would get more contaminated on a volume basis. Combine that with high temps and sun and it doesn’t seem like an unreasonable amount to me.

I use about 36-48oz per day in a 13,000 gallon pool under similar conditions, minus the temp- more like 80 degrees here.

 

[Danylukburton]

I’m not an expert, but it would make sense to me that they do. Each bather is theoretically going to introduce a fixed amount of organics regardless of the size of the pool. In less water, less dilution would occur so the water overall would get more contaminated on a volume basis. Combine that with high temps and sun and it doesn’t seem like an unreasonable amount to me.

I use about 36-48oz per day in a 13,000 gallon pool under similar conditions, minus the temp- more like 80 degrees here.

Thanks for the confirmation. I will carry on!

 

[Danylukburton]

Merged threads - TFP Mod
Pool store told me my phosphate level is 2700 and sold me phosphate remover and told me to put it in every 6 hours because it was so high (??!!)

Well, I haven't done any of that yet, and read it can turn the pool cloudy. Pool is beautiful and clear, but I do use an excessive amount of liquid chlorine to stay at minimum levels for my cya.

Expert opinion needed! Should I use the phosphate remover (at the labeled dosage) ? Will this help with chlorine usage?

 

[Flying Tivo]

Return it, no need!

 

[Richard320]

What is an "excessive amount of liquid chlorine"?

If your pool is in full sun all day and you have a lot of swimmers, 4 FC loss per day would be fairly normal. Are you using more than that? And are you sure your liquid chlorine is fresh and full-strength? When you add X amount, does it bring things up to where it should?

If you think you have algae, run the FC level up a little after dinner, leave things to mix well, and run the Overnight Chlorine Loss Test. If you pass, nothing's growing. If you fail, you've already gotten a head start on the SLAM Process.

You especially don't want to use phosphate remover if you have live algae in the pool. Phos-free instructions even say so, but the pool store clerks seem to ignore that part. Read it for yourself --- right about the print button.

Important: Algae must be treated prior to testing and lowering phosphates. Chlorine must be under 5ppm before testing phosphates.

Phosfree® - NaturalChemistry

naturalchemistry.com

If there's no algae, then phos-free won't help the chlorine consumption. But if you're a belt-and-suspenders kind of guy, or if you get lazy about adding chlorine, try it. It won;t hurt anything but your wallet. Just don't do it a week or less before your kid's birthday party, because we have seen many,many, many threads about milky water after phosphate remover.

 

[Danylukburton]

4 FC loss per day would be fairly normal. Are you using more than that? And are you sure your liquid chlorine is fresh and full-strength? When you add X amount, does it bring things up to where it should?

Thanks for the great info. My pool is small (1,000 gals) I have 3 kids that use it 2+ hours each day. I found this formula for FC usage when searching old posts on this site:

One person-hour in a 20,000 gallon pool requires (1 person-hour)*(4 g/person-hour)*(1000 mg/g)/(75708 liters) = 0.053 ppm FC to oxidize the bather waste

So using this formula for my 1000 gallon pool ( 3785 liters) = 1 * 4 * 1000/3785 = 1.056ppm FC per hour per bather. Which means if I have 3 bathers in for 2 hrs I'm over 6ppm just to oxidize their load.

But I am adding 12oz (12.5%) each evening to stay at or above 5ppm (CYA is 50-60). I am still a novice, but this seems like a lot to me. According to pool math 1oz =1ppm using 12.5% in a 1,000 gallon pool.

I got the Chlorine from inside a Leslie's store on 7/17 and the date on the bottle is 063020. I store it inside so I think it should be pretty potent, but I have never actually checked right after I add it. This is a great idea. Would I give it a half an hour to circulate after adding?

I don't see any signs of algae in the pool at all. Before I switched from pucks (~2.5 weeks ago) the water was getting cloudy, but now it's very clear. It is well water - if that makes a difference?

Thanks again for the advice!

 

[PoolNewb2020]

You said your pool was cloudy when you used pucks, did you SLAM it after converting to liquid chlorine?
I would perform an OCLT just to be sure.

 

[Deb04]

Since you’re in MA, good chance you have an Ocean State Job Lot near by. Their 12.5% liquid chlorine is $2,99 for a full gallon.