Vacation plan

[mike_jones]

Here's what I'm thinking:

We'll be out of town for 14 days.

I just emptied and re-filled my 16k gallon plaster pool (new pool owner). CYA currently just below 30, I'd guess 28 (using the Taylor K-2006C). Other measurements are: Ph: 7.8; Alk: 150; Calc: 320.

I'm in the southwest, plenty of sun out here. But my backyard set-up allows for relatively small direct sunlight. Seems I'm losing about 1.4 ppm FC each day. Will continue to test to verify this FC attrition. For the sake of this post, let's assume I actually do lose 1.5 ppm FC each day on average.

I'm thinking I'll bring FC up to 20 the morning we leave, AND add three 3" Trichlor tablets in the floaters. That will add an additional 10 ppm FC and 6ppm CYA. I'd set the floaters to the lowest water flow setting.

I'm not sure if when FC levels get high, the addition of tablets will have the same effect as when the FC is lower. Or, if my current low CYA levels will have an impact on FC longevity.

Recommendations to get a SWG installed, or to get that automatic chlorine pump, or to have neighbors/friends come check on the pool are not what I'm searching for. Specifically interested in the feasibility of my plan.

Thanks for the help!

 

[Texas Splash]

I think your plan in increase the FC and add some tabs is fine. Since your CYA is currently at only at about 30, the SLAM FC level is 12. Going higher than that (i.e. 20) is generally not advised, but with a plaster pool and plenty of shade it may not be a huge deal.

 

[mike_jones]

Here's what I'm thinking:

We'll be out of town for 14 days.

I just emptied and re-filled my 16k gallon plaster pool (new pool owner). CYA currently just below 30, I'd guess 28 (using the Taylor K-2006C). Other measurements are: Ph: 7.8; Alk: 150; Calc: 320.

I'm in the southwest, plenty of sun out here. But my backyard set-up allows for relatively small direct sunlight. Seems I'm losing about 1.4 ppm FC each day. Will continue to test to verify this FC attrition. For the sake of this post, let's assume I actually do lose 1.5 ppm FC each day on average.

I'm thinking I'll bring FC up to 20 the morning we leave, AND add three 3" Trichlor tablets in the floaters. That will add an additional 10 ppm FC and 6ppm CYA. I'd set the floaters to the lowest water flow setting.

I'm not sure if when FC levels get high, the addition of tablets will have the same effect as when the FC is lower. Or, if my current low CYA levels will have an impact on FC longevity.

Recommendations to get a SWG installed, or to get that automatic chlorine pump, or to have neighbors/friends come check on the pool are not what I'm searching for. Specifically interested in the feasibility of my plan.

Thanks for the help!

Thanks for the reply.

Still learning about the TFP school of thought... I get that SLAM raises FC, and you monitor the reduction in FC to see if organics are being gobbled up by the FC. But what's the downside of raising FC amounts above the SLAM level?

I'm sure there's reasons a person shouldn't be in the water with certain chlorine levels, but that's not applicable since we'll be out of town. Are there risks to my pool system/pump/filters/anything else? Sounds like the fact that it's plaster doesn't raise an alarm for you, interested in the reasoning behind that too.

Thanks for the help.

 

[Texas Splash]

But what's the downside of raising FC amounts above the SLAM level?

We caution owners who exceed the SLAM FC level not to swim. Pools with liners we try to avoid as well except for a brief 24-hr elevated FC level for Mustard Algae. Also, when the FC is above the SLAM level, the FC tends to fall much faster since there's not enough CYA to bind to, thereby making the additional chlorine a bit useless, especially in the sun. But in your case, with plaster and in the shade, if you exceed the SLAM level a bit with no swimmers it's not the worst thing.

 

[mgtfp]

Also keep in mind that your daily FC-loss is actually a percentage of the current FC-level. If for example (don't know your actual numbers) your current loss of 1.5ppm is based on an FC of let's say 5ppm. That means your loss is 30% per day.

Applying those 30% to an FC of 20ppm, your daily loss on day 1 will be 6ppm. Then you'll be down to 14ppm and you'll lose about 4ppm the day, bringing you down to 10ppm on day 2. And so on.

Your initial burst won't last long.

I use that method for vacations in winter (pool remains open, and even the SWG runs all year). In winter, I lose something like 2.5% of FC per day, pool is completely shaded for the two peak winter months. On a recent 4 week vacation (just after the southern winter solstice) I raised my FC to about 21ppm and turned everything off. When I came back, my FC was at 9ppm, pretty much were I expected it to be.

But in summer, when my daily loss is more like 20-30%, this doesn't work for longer periods, and I keep the SWG running, with some precautions that the pump doesn't run dry and ideally someone checking the skimmer.

It still makes sense to initially raise FC to SLAM, which also helps to kill off any remaining organics. But then you need a plan to regularly add some chlorine. That could be someone dropping by and adding agreed amounts of liquid chlorine, or having a few pucks floating if your CYA level can afford that.

 

[mike_jones]

Also keep in mind that your daily FC-loss is actually a percentage of the current FC-level. If for example (don't know your actual numbers) your current loss of 1.5ppm is based on an FC of let's say 5ppm. That means your loss is 30% per day.

Applying those 30% to an FC of 20ppm, your daily loss on day 1 will be 6ppm. Then you'll be down to 14ppm and you'll lose about 4ppm the day, bringing you down to 10ppm on day 2. And so on.

Your initial burst won't last long.

I use that method for vacations in winter (pool remains open, and even the SWG runs all year). In winter, I lose something like 2.5% of FC per day, pool is completely shaded for the two peak winter months. On a recent 4 week vacation (just after the southern winter solstice) I raised my FC to about 21ppm and turned everything off. When I came back, my FC was at 9ppm, pretty much were I expected it to be.

But in summer, when my daily loss is more like 20-30%, this doesn't work for longer periods, and I keep the SWG running, with some precautions that the pump doesn't run dry and ideally someone checking the skimmer.

It still makes sense to initially raise FC to SLAM, which also helps to kill off any remaining organics. But then you need a plan to regularly add some chlorine. That could be someone dropping by and adding agreed amounts of liquid chlorine, or having a few pucks floating if your CYA level can afford that.

Ahhh interesting! Make sense it's a % of total FC dissipating, not just a static number. Very helpful!!

 

[mike_jones]

Update: Gone for 15 days. Loaded up before I left with 2 gallons of 12.5% chlorine, and put four 8oz trichlor tablets in the floaters.

Friend came by halfway through, put an additional 4 trichlor tablets in the floaters. I instructed him to "put the gallon of pool shock in the pool", I guess he chickened out and only put a couple splashes in lol.

Pool is clear! Some leaves and stuff, but no algae!

CYA: 47 FC: 7.4

 

[Mdragger88]

Great
Side note*
I think it’s funny that so many people are ok with touching tabs (which will burn your skin) & inhaling the fumes/dust from solid chlorine products but are scared to pour a little bleach into thousands of gallons of water - something housewives have handled daily for 100+ years & no one batted an eye.