Pool Math Analysis and Vacation Question

[luma7]

Hi All,
We've been using TFP methods with our pool since it was opened 9/2020 and have always had wonderful water quality, thank you!

With short notice, we've decided to go on a two week vacation and we're thinking about how to handle the pool while we're gone. No one in our area has a pool and we are not comfortable asking those without chemical knowledge to handle acids for us so we have to figure out how to leave it and hope for the best. Three questions for any experts out there on Pool Math, PH, and unattended chemistry levels...

With a SWG, the chlorine often self manages (other than when the cell stopped working recently). My spouse adds (everything but most frequently) CYA & MA when needed based on Pool Math. We tried doing some analysis with the data out of the app; however, we did not see how to export the logs for when he added chemicals in order to do a regression analysis to calculate reliable projections for the water quality at any given time based on the numbers the day we leave.
Question 1: Does anyone know how to export both the logs and the maintenance at the same time?

Based on some simple averaging, it appears our PH goes up .1 per day without us adjusting anything. If we take it down to 7 the morning we leave, then by the time we get back (15 days) it should be ~8.5. As long as the FC is maintained by the SWG, and is protected somewhat by CYA at the upper limit the day we leave, then I think we are fine with that and plan to add chemicals the day we return. I noticed several threads where there was a suggestion to slam the pool before leaving; however, we're uncertain about doing that when our PH requires management to bring it down. Turning up the aquapure or adding liquid chlorine always raises the ph so we'd have to put far more acid in to do that. Question 2: Is it really necessary to slam the pool before a trip?

Finally, we have a Catch a Kid Net we put over the pool when not in use. Several threads indicated that covering the pool while we're gone might help with chemistry. Is it worth going through the trouble of finding something on short notice that will go under the CAK? Question 3: find a cover or leave open?

Here are random items in case they help with answers:

• We are in a location where the pool is very hot and in full sun this time of year (water temps up to 93 if we don't manage it and we won't be here to do that)
• No fountains or bubblers are running (they've been on ~4 days this year). It is used by a splashy kid several days a week; however, no splashing will occur while we're gone
• Since we're entering the time when there is more sun on the pool and more use of the pool, we've turned up the aquapure which drives up our PH (even more than our plaster brings it up). Right now, we're adding .25-.5 gallon 31.45% MA every ~10 days.
• Our pool is set for auto-fill on city water that has been tested at PH 7-8.7, TA 27.4, Chlorine .86-1.48 ppm (should not get much fill during this two weeks)

Several charts below, if any of this data is helpful. Thank you in advance for the help. Really appreciate the community here.

All the best,
Darla

Manually created table of MA added this year:

Date	Volume	Measurement
4-May	0.5	gallon
24-Apr	0.25	gallon
21-Apr	0.5	gallon
4-Apr	0.5	gallon
13-Mar	16	oz
16-Jan	32	oz

Recent Pool Logs
==========================================
Snoopy
------------------------------------------
Build Type: Plaster
Volume: 19500 gallons
------------------------------------------
Latest Test Result Summary:
FC: 8.0 (an hour ago)
CC: 0.5 (an hour ago)
pH: 7.5 (an hour ago)
TA: 60 (an hour ago)
CH: 475 (an hour ago)
CYA: 80 (an hour ago)
SALT: 3600 (an hour ago)
TEMPERATURE: 86° (3 days ago)
CSI: -0.35 (an hour ago)
==========================================
------------------------------------------
Test Results 05-08-2022 @ 10:09 AM
------------------------------------------
Free Chlorine: 8.0
Combined Chlorine: 0.5
pH: 7.5
Total Alkalinity: 60
Calcium Hardness: 475
CYA: 80
Salt: 3600
CSI: -0.35

------------------------------------------
Chemical Addition 05-05-2022 @ 02:03 PM
------------------------------------------
+ 6 Pounds of CalciumChloride

------------------------------------------
Test Results 05-05-2022 @ 01:48 PM
------------------------------------------
Calcium Hardness: 400
CSI: -0.47

------------------------------------------
Test Results 05-05-2022 @ 01:44 PM
------------------------------------------
Free Chlorine: 6.5
CSI: -0.59

------------------------------------------
Test Results 05-05-2022 @ 01:42 PM
------------------------------------------
pH: 7.2
CSI: -0.59

------------------------------------------
Test Results 05-05-2022 @ 01:41 PM
------------------------------------------
Salt: 3600
CSI: -0.02

------------------------------------------
Chemical Addition 05-05-2022 @ 01:36 PM
------------------------------------------
+ 4.5 Pounds of DryStabilizer

------------------------------------------
Test Results 05-05-2022 @ 11:00 AM
------------------------------------------
Temperature: 86°F
CSI: -0.44

------------------------------------------
Chemical Addition 05-04-2022 @ 01:00 PM
------------------------------------------
+ 40 Pounds of Salt

------------------------------------------
Chemical Addition 05-04-2022 @ 12:59 PM
------------------------------------------
+ 0.5 Gallons of Baume31

------------------------------------------
Test Results 05-03-2022 @ 11:44 AM
------------------------------------------
Free Chlorine: 5.5
Combined Chlorine: 0.5
pH: 7.8
CYA: 50
CSI: -0.01

Chart of FC & PH over the last year. Dip to 0 in April of this year was when aquapure stopped working properly for about a month.

 

[ajw22]

Set your SWG to a good generation % and go on vacation. Let your FC rise while on vacation. With CYA 80 your pool is safe to swim until FC of 32. When you get back you can let the FC drift back down.

Your pH will climb while you are away and no damage will happen from a pH in the 8's for 2 weeks or so. The pH will reach an equilibrium with your TA somewhere in the 8's and sit there until you get back.

You have an autofill to handle evaporation while you are away.

So your risks with your pool are no greater then a major problem with your house.

Enjoy your trip.

 

[mgtfp]

What Allen said.

Just one question: How do you measure pH? There are quite a few surprisingly high values in your log. Like pH 9.0. With a TA around 70 and CYA at 80, this is very unusual. I wouldn't expect your pH to rise much above 8. Maybe 8.1 or 8.2, but not 9.0.

 

[luma7]

Set your SWG to a good generation % and go on vacation. Let your FC rise while on vacation. With CYA 80 your pool is safe to swim until FC of 32. When you get back you can let the FC drift back down.

Your pH will climb while you are away and no damage will happen from a pH in the 8's for 2 weeks or so. The pH will reach an equilibrium with your TA somewhere in the 8's and sit there until you get back.

You have an autofill to handle evaporation while you are away.

So your risks with your pool are no greater then a major problem with your house.

Enjoy your trip.

Thanks, Allen, this is great news. Appreciate the quick reply. It is a load off our minds.

 

[luma7]

What Allen said.

Just one question: How do you measure pH? There are quite a few surprisingly high values in your log. Like pH 9.0. With a TA around 70 and CYA at 80, this is very unusual. I wouldn't expect your pH to rise much above 8. Maybe 8.1 or 8.2, but not 9.0.

We're using the TF 100 test kit. You're right about high values. I thought plaster was supposed to settle after a year or so but ours has not yet. It constantly drifts to 8ish and if we happen to add chlorine or bump up the Aquapure around that time it spikes up. I'm not sure the scale actually goes to 9 but the color was so dark we estimated it at that.

 

[ajw22]

We're using the TF 100 test kit. You're right about high values. I thought plaster was supposed to settle after a year or so but ours has not yet. It constantly drifts to 8ish and if we happen to add chlorine or bump up the Aquapure around that time it spikes up. I'm not sure the scale actually goes to 9 but the color was so dark we estimated it at that.

When you get back from your trip let’s discuss that more and try and get your pH under control.

 

[mgtfp]

Hadn't thought about the pool still being relatively new, there might still be a pH drift from the plaster. But as Allen said, enjoy your trip and don't worry about the pool, it can look after itself easily for two weeks with a SWG