My Pool After 20 Day Vacation

[bobandsherry]

Almost 3 weeks on vacation and came back to pool that is clear. The pH was high at 9.0 but I expected that as my pH is always increasing.

The FC also dropped from 5.2 to 2.8 even though SWG was set to 55. I had expected it to hold steady or be slightly higher than when I left. The only difference in my usual maintenance was I dropped pump RPM down to 1250 and ran 24 hours while I was gone, I did this in case power went out and mechanical timer got out of sync with my regular pump hours. So perhaps the lower flow reduces the efficiency of the salt generation? Something I'll keep an eye on.

Otherwise just a little dirt due to storms that hit while away, so other than adding acid to drop the pH I just need to get my vacuum running to clean the bottom.

Results before/after vacation:
FC 5.2/2.6
CC 0.0/0.0
pH 7.6/9.0
TA 80/80
CH 350/350
CYA 70/70
Temp 78/78

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[Newton4mark]

That's a good vacation!



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[Richard320]

Who knows what blew in and used up the FC?

Sounds like you have our way of maintenance figured out.

 

[ping]

You might want to inspect the cell for scale.

I calculated the pool was getting 3.6ppm of chlorine a day with those settings if the cell was working as it should have been.

What were your settings before you left; pump time, RPM, and output%? I want to compare how much FC the SWG was making before you left.

In the last few weeks I have had to increase my pump run time and output% for my pool's FC to maintain the desired level.

 

[pooldv]

Nice job! And nice pool!

I agree with Ping's line of thinking that more sun and more heat is leading to higher FC usage as the days get warmer and longer. I have also had to increase percentage and run time for my SWG to keep up. And the trees aren't helping me that much at the moment either.

 

[bobandsherry]

You might want to inspect the cell for scale.

I calculated the pool was getting 3.6ppm of chlorine a day with those settings if the cell was working as it should have been.

What were your settings before you left; pump time, RPM, and output%? I want to compare how much FC the SWG was making before you left.

In the last few weeks I have had to increase my pump run time and output% for my pool's FC to maintain the desired level.

The cell was installed new last September. I inspected it a month ago and there was literally no scale build up. Prior to my vacation I had been running it at 45% (was holding in the 4-5 FC range). I increased to 55% as I figure better to be over than short while gone.

Prior to vacation pump was set to run 9AM-8PM, 1750 RPM for first 3 hours and then dropped to 1500 RPM for remainder of time. SWG was set to start 30 min after and 30 min prior to pump cycle. As suggestion from another here, I lowered RPM and set to run 24 hours just to be sure any power outage didn't occur and throw my SWG mechanical timer off from the pump timer.

While I was gone the temps did jump to over 90 for a week and was at nearly 100 for three of the days. However pool temp was still the same at 78 degrees as when I left, so unless it raised and lowered it was basically unchanged. Maybe it's just the change in the longer days now more sun and burn off and it's just time to increase the output %.

- - - Updated - - -

Who knows what blew in and used up the FC?

Sounds like you have our way of maintenance figured out.

Yeah, the suggestions I've picked up here made my extended trip painless upon return. I thought this highlight the benefit of using the TFP method, seems to work really well!

 

[Killer95Stang]

Looks good.... Im currently on my last day of a 3 week vacation to Japan and I can't wait to get back to the pool. Unlike you, I put the solar cover on before I left and lowered the swcg down from 35% to 25%, since the cover will cut down on fac usage. About 1-1/2 weeks into the trip, I had a neighbor come down to add some MA. My plan is to balance the water when I get home and probably throw the Discovery in for a coupke cycles... then jump in and enjoy the rest of the week before I go back to the grind.

 

[bobandsherry]

I found that upon my return I increased my SWG output to 100% for the past day, FC has climbed back to 5.0 in that day's time. That is an increase of 2.5ppm plus the offset of the burn off loss in one day. Does that indicate that cell is operating as it should?

 

[Killer95Stang]

You would have to look in the manual for the output per hour for your swg, then guestimate a little on daily usage to subtract from the stated output.

If you raised 5 to 6 ppm in a day, that sounds like it is humming along just fine.

 

[ping]

Before vacation the SWG was adding about 1.2ppm of FC each day which is very reasonable for the water temp and time of year. The SWG is producing chlorine as the level did increase with a longer run time. For peace of mind, I suggest running an OCLT to rule out organics. I have a feeling it is that time of year that the SWG needs more time to keep up with the demand from the sun.

 

[bobandsherry]

Before vacation the SWG was adding about 1.2ppm of FC each day which is very reasonable for the water temp and time of year. The SWG is producing chlorine as the level did increase with a longer run time. For peace of mind, I suggest running an OCLT to rule out organics. I have a feeling it is that time of year that the SWG needs more time to keep up with the demand from the sun.

Thanks ping for the response. I did a OCLT about 2 weeks before vacation just to have a peace of mind nothing was going to happen. There was no change from night test to morning test.

Pool was finished last July, and there were issues with the salt unit that PB installed (had an AutoPilot SWG unit that would randomly put itself into Boost mode), PB replaced with AquaRite in September. So this is first Spring with operating the pool and nothing to refer back to in Summer as to what the % output since I didn't have the AR unit then. So I'll just understand for now that I was under on my SWG output % need which resulted in the FC dropping while I was gone and that higher than normal heat in that time also contributed. Now that FC is back to higher normal level I've set the SWG to 60% and monitor how that runs for the rest of the year.

 

[bobandsherry]

You would have to look in the manual for the output per hour for your swg, then guestimate a little on daily usage to subtract from the stated output.

If you raised 5 to 6 ppm in a day, that sounds like it is humming along just fine.

Nothing in the manual on output, but search found a source that shows 0.965/lbs per day. Now what it doesn't indicate is what is a day. 24 hour run time or 8 hour run time. Will have to continue the search on that. Thanks

 

[ping]

A T-9 cell can output .7lbs. of chlorine in 24 hours of run time if the output is set to 100%.

That is 11.2 ounces of chlorine gas and if you use PoolMath and enter your gallons and ounces of chlorine gas in effects of adding chemicals at the bottom of the page you can get how many ppm of fc the SWG will produce in your pool.

 

[bobandsherry]

Ping - what did you reference for source of the T-9 output? I had looked on Hayward's site and didn't find any details but did find info on this site (they sell the T-9) and it shows as .965. Based on other sources the T-15 generated 1.4lbs around so .9lbs seems to be right (mathematically), the .7 would seem low as that would be half the T-15. If my math is right then the .965 would be 15.4 ounces of chlorine gas.

If you have Hayward link for reference that would be great so I can be sure what the output is. Depending on what the actual output is my cell is producing either 6.5 FC or 8.9 FC in 24 hour period. Using my 1 day change with cell at 100% (run time of 10 hours) my FC went from 2.6 to 5.0. So either my daily use is either 0.3 (2.6+2.7-5.0) or 1.3 (2.6+3.7-5.0). I hadn't looked into calculating the FC generated and the daily use so this has been helpful for my understanding and I can then back in to what my SWG output should be based on daily FC burn ratio.

Thanks

 

[ping]

I was using this site, Welcome to Discount Salt Pool - Saltwater Chlorine Generators - Chlorinators that has a brand comparison.

However, you are right with your numbers. Hayward's website does list the actual output of each cell and the total expected output for the life of the cell. If you compare the cells you will get the output numbers.

Thanks for pointing this out!

 

[bobandsherry]

Thanks ping, I had saw the capacity output but confused it with the capacity of the cell (lifetime) and that didn't make sense. I see now it's the expected yearly This was very helpful. I've created a spreadsheet that calculates the expected change (FC, pH and Salt) based on run time and output %. I guess a spreadsheet may already exist but it was useful as it helped me to understand the details to create it, not just the output.