3 weeks away - how to keep levels up?

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Poiks

Poiks

Bronze Supporter
Jun 22, 2019
67
McKinney, TX
I normally use liquid bleach and muriatic acid routinely to maintain my pH and chlorine levels. I'm going to be away for three weeks, and I'm wondering if there's some way I can keep my water chemistry in an acceptable range without trying to find someone to test it for me.

On a typical day this time of year, I add 8 oz muriatic acid and about 28 oz of bleach to the pool. I keep a couple of chlorine tablets in the feeder shown, open only slightly, primarily to keep my CYA up above the recommended minimum. Each tablet lasts over a week at the current consumption rate.

I'm thinking of loading up the tablet feeder and hoping for the best while I'm away. If anyone has thoughts on a better approach--I'm not going to ask my neighbors to add chemicals--I'd appreciate any advice in terms of pH and chlorine management during time away. Thanks!IMG_0510.jpeg
 
Initially raising fc with liquid chlorine & also employing The feeder may get you by for a week or so but 3 weeks is a stretch.
And what about the skimmers? Someone will need to check those. Maybe that someone could pour a little bleach in too?
Do you have a cover of any kind?
 
Poiks said:
I'm going to be away for three weeks, and I'm wondering if there's some way I can keep my water chemistry in an acceptable range without trying to find someone to test it for me.

On a typical day this time of year, I add 8 oz muriatic acid and about 28 oz of bleach to the pool. I keep a couple of chlorine tablets in the feeder shown, open only slightly, primarily to keep my CYA up above the recommended minimum. Each tablet lasts over a week at the current consumption rate.
Click to expand...

In your 14000-gallon pool, 28 fluid ounces of 10% bleach raises FC by 1.6ppm. So that's how much you're losing each day.

An 8-ounce Trichlor tablet raises FC by 3.9ppm. But you say tablets take over a week to dissolve -- let's say 10 days -- which means that each tablet adds 0.39 ppm FC per day on average. Rounding that to 0.4ppm, you'll need four tablets in the feeder to keep up with your 1.6ppm/day FC usage.

It's unclear from your PoolMath logs exactly what your CYA level is, but I'm guessing it's around 50ppm. Each of those four tablets will add 2.4ppm CYA, so by the time they're dissolved your CYA will be 60ppm.

Minimum FC for 60ppm CYA is 5ppm (target is 7-9ppm), and SLAM level is 24ppm.

So if you can't get someone to come in and add chlorine even once while you're away, you might be able to get by (barely) if you raise your FC to 24ppm just before you leave, and put 4 tablets in the feeder.

The tablets will dissolve over 10 days, maintaining FC at 24ppm for that entire period.

Then, over the next 11 days until you return, the pool will lose 1.6ppm FC per day: 17.6ppm total. That will leave your FC at 24 - 17.6 = 6.4ppm, just barely above the minimum level of 5. As soon as you get back, test FC and pour in a couple quarts of chlorine to raise it to the high end of the target range.

This all assumes that your FC loss really is 1.6ppm/day, and that your CYA concentration really is 50ppm. If FC loss is higher -- even just 2ppm/day -- you'll lose too much over the 11 days that the feeder is empty. So the best strategy is to dissolve more tablets more slowly: If you can fit 8 (or 10) tablets in the feeder instead of 4, and lower the water flow through the feeder to make them last 20 days instead of 10, you'll come back to a pool that's still close to SLAM level.
 
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Note that the acidic water from the tablets in the feeder will eventually murder your heater.

Better to use Trichlor tablets in a floater so it is not near any pool equipment.
 
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1.6 ppm/day fc loss seems very low for texas in july. I see you have went below minimum a few times that you recorded your fc tests. That is a risky game, riding the fence. Best to aim for high target so if life happens things don’t go downhill fast.
FC/CYA Levels
I also see lots of baking soda & acid additions that don’t really jive with the ph & ta logs.
It can seem like an extra step but try to log your results first then your additions.
It makes the logs much more useful if you need to look back .

Have you considered a swcg to feed your pool whether you are home or not?
 
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Mdragger88 said:
Initially raising fc with liquid chlorine & also employing The feeder may get you by for a week or so but 3 weeks is a stretch.
And what about the skimmers? Someone will need to check those. Maybe that someone could pour a little bleach in too?
Do you have a cover of any kind?
Click to expand...
Good point about the skimmers--I'll have to ask a neighbor to check those for me. I suppose I could ask him to dump a gallon of bleach in a couple of times, too. No cover at all, and the pool is in bright sun most of the day.
 
ajw22 said:
Note that the acidic water from the tablets in the feeder will eventually murder your heater.

Better to use Trichlor tablets in a floater so it is not near any pool equipment.
Click to expand...
Thanks--I'm not familiar with Trichlor tablets, having always used liquid bleach--and Amazon search isn't very helpful. How are they different than the 3" tablets for the feeder?
 
Mdragger88 said:
1.6 ppm/day fc loss seems very low for texas in july. I see you have went below minimum a few times that you recorded your fc tests. That is a risky game, riding the fence. Best to aim for high target so if life happens things don’t go downhill fast.
FC/CYA Levels
I also see lots of baking soda & acid additions that don’t really jive with the ph & ta logs.
It can seem like an extra step but try to log your results first then your additions.
It makes the logs much more useful if you need to look back .

Have you considered a swcg to feed your pool whether you are home or not?
Click to expand...
You're right about my going below the minimum fairly routinely. Because I've never seen any algae, I've gotten a bit lax about it. I'll adjust my routine accordingly.

The baking soda thing lately is weird. As you've seen, I've had several instances where the total alkalinity dropped and I needed baking soda to boost it. I have no idea what could be causing that or what I should do about it.
Also--because I have felt like things are humming along, I'm only testing on weekends, and adjusting my daily "dosing" of bleach and acid based on how it looks like things are going when I do my weekend tests. In past seasons I've needed to add about 32 oz of bleach daily during summer--not sure if that is in the normal range.

I know nothing about swcg's at all--are they a big deal to retrofit?
 
Poiks said:
You're right about my going below the minimum fairly routinely. Because I've never seen any algae, I've gotten a bit lax about it. I'll adjust my routine accordingly.

The baking soda thing lately is weird. As you've seen, I've had several instances where the total alkalinity dropped and I needed baking soda to boost it. I have no idea what could be causing that or what I should do about it.
Click to expand...
Acid additions are the only way to lower ta- like via trichlor tablets
Poiks said:
Also--because I have felt like things are humming along, I'm only testing on weekends, and adjusting my daily "dosing" of bleach and acid based on how it looks like things are going when I do my weekend tests. In past seasons I've needed to add about 32 oz of bleach daily during summer--not sure if that is in the normal range.
Click to expand...
No need to micromanage ph with daily additions- as mentioned the tabs are also acidic so you’re inadvertently double dosing with your blind acid additions.
Here’s what each dissolved tab will do to your water
IMG_6784.jpeg
Poiks said:
I know nothing about swcg's at all--are they a big deal to retrofit?
Click to expand...
Generally it goes Remove tab feeder, install swcg. You want a unit rated for at least 2x’s your pool’s volume. Then test your current salt level & add how much you need to reach the target for your particular swcg.
www.troublefreepool.com

Salt Water Chlorine Generators

Salt Water Generators are designed to produce small amounts of chlorine continuously. This is perfect for day to day use and reduces work for the homeowner.
www.troublefreepool.com www.troublefreepool.com
 
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Mdragger88 said:
1.6 ppm/day fc loss seems very low for texas in july. I see you have went below minimum a few times that you recorded your fc tests. That is a risky game, riding the fence. Best to aim for high target so if life happens things don’t go downhill fast.
Click to expand...

I thought that too. In Nj since we’ve had an upper 80 degree week and lots of sun I’ve lost about 2-2.5 FC daily. My pool is only 10k gal and there are some parts of the day it’s half shaded or more if there are clouds.
 
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Mdragger88 said:
Acid additions are the only way to lower ta- like via trichlor tablets

No need to micromanage ph with daily additions- as mentioned the tabs are also acidic so you’re inadvertently double dosing with your blind acid additions.
Here’s what each dissolved tab will do to your water
View attachment 511527

Generally it goes Remove tab feeder, install swcg. You want a unit rated for at least 2x’s your pool’s volume. Then test your current salt level & add how much you need to reach the target for your particular swcg.
www.troublefreepool.com

Salt Water Chlorine Generators

Salt Water Generators are designed to produce small amounts of chlorine continuously. This is perfect for day to day use and reduces work for the homeowner.
www.troublefreepool.com www.troublefreepool.com
Click to expand...
OK-- thank you for the advice on not adding acid daily. That 8 oz was based on daily testing in the past, but I'll see how it goes. This morning my TA was down to 50 and required 5 POUNDS of baking soda. This has never happened before and I have no clue why it's happening.
 
Poiks said:
OK-- thank you for the advice on not adding acid daily. That 8 oz was based on daily testing in the past, but I'll see how it goes. This morning my TA was down to 50 and required 5 POUNDS of baking soda. This has never happened before and I have no clue why it's happening.
Click to expand...
50 is fine if you’re manually chlorinating with liquid chlorine - let it be. Then see what the ph does. It will probably hang out a while in the high 7’s.
The lower the ta the slower the ph rise.
If you’re going to continue to use tabs you will need to keep ta a bit higher since they are acidic & you will stay on this merry go round.
 
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Mdragger88 said:
50 is fine if you’re manually chlorinating with liquid chlorine - let it be. Then see what the ph does. It will probably hang out a while in the high 7’s.
The lower the ta the slower the ph rise.
If you’re going to continue to use tabs you will need to keep ta a bit higher since they are acidic & you will stay on this merry go round.
Click to expand...
Thank you--I finally broke down and asked a neighbor who has a pool to take care of it for me. He also does his chemicals himself, so I trust him to deal with it. If he doesn't volunteer to actually test the water, I'll just ask him to add a gallon of bleach every 4 days while we're gone. Any thoughts on whether the pH and TA can be ignored for 3 weeks?
 
If you’re using the tabs that will keep ph in check & may lower ta some so you may want to keep ta around 70 or so until you return & can get your pool back on the full liquid diet.
 
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Hi all, now that I'm back thought I'd update the status of the pool, for anyone interested.
Before I left, I did the following:
  • Increased the tablets in my chlorine tablet feeder to 3
  • Increased flow rate on the feeder from my normal 0.5 (almost no flow) to about 2 or 2.5
  • Arranged a neighbor to add 1 gallon of 10% bleach to my pool every 4 days (most recently July 30)
Returned after three weeks to find the following:
  • Free chlorine: 0
  • Tablet feeder empty
  • pH: off the charts (after adding 12 oz muriatic acid, still off the charts)
  • Total Alkalinity: 95
  • Thankfully, no visible algae
I've added a gallon of bleach and will recheck in a bit. I'll also keep checking pH until I get it down to 7.0-7.2 as recommended in the app for high TA, and the only thing I can think of to aerate the pool is to keep running the blower in the spa.

I guess I feel pretty lucky all things considered.

Any other advice appreciated, thanks for any thoughts and for the previous feedback.
 

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