Switching from Frog to SWCG

[P00LNerd]

Also, the higher ppm of chlorine won't give off an odor unless it's reacting with organics in the pool. So if you have the pool clear of algae then you shouldn't smell the chlorine.

I keep a solar cover on the pool most of the time, and I only ever smell chlorine when first removing that, at the lower FC targets I was running. I suspect what we mostly smell is CC, and that probably builds up under the solar cover.

 

[P00LNerd]

But in essence, a range IS good enough. The CYA/FC balance means you don't have to be managing your FC to 0.1ppm resolution...

PH/TA/CYA will remain fairly stable. PH/TA is going to vary based on the type of pool, your fill water, whether it rained last night, how much aeration is occurring, etc etc - the bottom line is that they are not going to SIGNIFICANTLY impact your water quality unless you are in a Plaster/Gunite pool, and you're way out of range. As long as they are balanced, your plaster pool won't scale or erode. Likewise with your SWG plates - as long as they are within reason, you'll be fine.

CYA is also fairly stable, and you can aim for a specific value - but the test is fairly subjective, so +/- 10ppm is about a good as you get. As this drives the FC number, having some 'wiggle room' on the FC makes sense.
Depending on the time of day, the specific location in the pool, and other variables, your FC number could fluctuate significantly - so providing a target range reduces the panic-induced lobbing in of chemicals to solve a perceived problem that doesn't exist.

If your PH/TA/CYA/FC are within the ranges suggested, you'll have no problems. Trying to aim for a specific number just means you'll be chasing the needle all the time...not 'Trouble Free'

Yeah, I know FC will always need a range, it's up and down every day. I really meant pH, TA, and CYA. If working up from below with fresh water, my simple math on corrective measures always nails the target, at least to within my ability to measure it.

So, if TA = 110 is better than TA = 80, don't tell me 80 - 120 when I can just as easily hit 110. Same with CYA (when not using dichlor) and even pH... all very easy to nail down to within measurement accuracy, doing some very simple math. It doesn't seem any of these factors drift fast enough to vastly affect my time spent on maintenance, but I'll admit I'm newer to this than all of you guys.

 

[P00LNerd]

Turn CSI off, it doesn't matter in a Vinyl pool.

Also, take note that I'm an engineer. Give me a measurement tool, and you're going to have to peel it out of my dead cold fingers. Turning it off goes against every fiber of my being.

 

[PoolStored]

My normal fill water is around TH = 260 ppm, but I have an option to use softened water, if I want to go to the trouble to drag a few hundred feet of hose from my garage to the pool.

Presently, I'm running around CH = 110 ppm. I'll make some time to test the fill water for CH later today.

Softened water removes CH, doesn't remove TA

 

[SJPoe]

So, if TA = 110 is better than TA = 80, don't tell me 80 - 120 when I can just as easily hit 110. Same with CYA (when not using dichlor) and even pH... all very easy to nail down to within measurement accuracy, doing some very simple math. It doesn't seem any of these factors drift fast enough to vastly affect my time spent on maintenance, but I'll admit I'm newer to this than all of you guys.

You're overthinking it.

As an engineer, think of it as a tolerance.

The TA number should be 70ppm +/- 20ppm
CYA should be 60 +/- 20ppm
FC should be 5% of your CYA minimum.
PH should be 7.6 +/- 0.4ppm

 

[P00LNerd]

Softened water removes CH, doesn't remove TA

Yep. Sorry, we may be crossing acronyms. My TH = 260 ppm is "total hardness", as that's what's typically measured on potable water. I haven't measured the CH of my water supply yet.

TH ~ CH + MH

 

[P00LNerd]

Okay TFP Experts. My first few days on the TFP / Pool Math method, and my chlorine loss seems to be much higher than I expected. Maybe this is normal?

I added 111 oz. of 10% yesterday (per Pool Math), getting up to 7 ppm, but 24 hours later I'm back down to FC = 3.6 ppm and it's calling for another 65 oz. of 10%. The solar cover was on all day, except roughly 3pm - 7 pm. There were roughly 6 man-hours spent in the pool, namely me with two kids for 1 hour, then three teens for 1 hour.

I'm used to losing only 1 ppm per day, maintaining FC = 2.5 - 3.0 per Frog / pool co. I was told to expect FC loss to stay the same at the higher level, but my loss today was 3x higher than usual. With cover installed almost the whole day, I'd have expected FC loss to be pretty low.

Possible complicating factors are that my TA and water temperature are both high. Everything is logged to my profile.

Any ideas?

 

[PoolStored]

There were roughly 6 man-hours spent in the pool, namely me with two kids for 1 hour, then three teens for 1 hour.

Yeah, that is a load. Not surprised at the loss.

 

[P00LNerd]

Yeah, that is a load. Not surprised at the loss.

Okay, I guess I understand your comments before about half-slamming the pool before a party, a little better now.

Sunday, I think there will be 5 teens in the pool for probably 3+ hours. I'm at CYA = 60. Where should I set FC before they come?

I'm not sure if my "man hours" is a good metric, but 5 teens x 3.5 hours = 17.5 hours.

 

[PoolStored]

12.

You can even test and add during the day. Pour it in, 5 minutes, good to go.

 

[P00LNerd]

12.

You can even test and add during the day. Pour it in, 5 minutes, good to go.

Wow. Still gotta get used to these numbers.

I had a party with 10+ people in the pool last year, and we kept the Frog dialed to FC = 1.0 ppm. I shocked with Oxy-Out the next day, just because, but no issues.

 

[P00LNerd]

12.

What's the guideline or basis for these numbers? I'd like to understand so I can adjust for future events of various size.

 

[PoolStored]

You went from 7 to 3.5. That is 3.5. I rounded to 4, gave it one more for protection, so 5.

Bottom of the range for your CYA is 7. Add the 5 and I came up with 12.

That way, at the end of the day, you should stay in range.

 

[SJPoe]

My pool loses (on average) 3-5ppm a day at 80ppm CYA and just the wife and I swimming for an hour or two. It gets full sun from about 9am through 6:30pm - on overcast days, its maybe 2-3ppm tops, on really hot sunny days, maybe 6-7ppm. I set my SWG to 40% and run 24x7. Based on the 'official' numbers for my RJ-60+, that should be 6ppm - I figure its closer to 5, and that seems to be born out with the levels in the pool. Its why I tend to run my pool at the high end (#TeamRunHot !!)

Overnight loss is less than 1ppm - heck, I lost less than 7ppm from October 27th through March 30th - thats a serious OCLT

Once you have your SWG dialed in, you can probably raise your CYA a little, to counteract the UV-induced losses - as long as you stay in range with your FC, its all good.

 

[P00LNerd]

Once you have your SWG dialed in, you can probably raise your CYA a little, to counteract the UV-induced losses - as long as you stay in range with your FC, its all good.

My CYA is presently at 60 ppm, and pool math is telling me to get it down to 45'ish.

With the 4" of rain we got last weekend, and then a bit more last night, the pool is within an inch of the top of the skimmer opening. But we have a week of "hot and dry" in the forecast, so maybe not the best time to drain a lot off, as I have to refill it from treated well water.

Oh, two more updates:

1. I got my salt test reagents today, from Amazon. Expiration dates were late 2025 and mid-2026, so no issues there.

2. My Salt test came in at just 600 ppm. I need to look up ideal for the RJ-45+, but I'm betting closer to 3k.

 

[PoolStored]

60 is a fine CYA for the Summer months.

Ideal for RJ is 3-4000. I keep it at 3500.

 

[P00LNerd]

60 is a fine CYA for the Summer months.

Ideal for RJ is 3-4000. I keep it at 3500.

Thanks!

I usually drain down about 3500 gallons in winter, as that gets the water below my skimmer, lights, and returns. It's also the size of the water truck that can back up my driveway, without much trouble. By my math, 3750 gallons will get me from 60 ppm to 45ppm on a 15k gallon pool, so I should land there next spring, either way.

Only question is, am I okay leaving it at CYA = 60 over the winter?

 

[PoolStored]

Yes, it will degrade and I will be surprised if it is above 20.

 

[P00LNerd]

Excellent!

So, I guess I need about 360 lb. of salt to get up to 3500 ppm. Should I just start adding it now, maybe a bag or two per day, until I'm up to target? Debating on best method of adding, such as dissolving in a separate bucket before pouring in, versus just dumping whole bags of rock into the pool.

 

[PoolStored]

You can. Do you have the SWCG? Dump it in the shallow end and brush until dissolved. I tend to do 4-5 bags at a time and depending on water temp, takes 5-10 minutes.

Many of us swear by "diamond crystal solar salt."