How often should I change my pool's water?

[ti_chris]

Hi,

I'm in California and trying to be water-wise and figure out what's the rate at which we should be changing the pool's water. I'm not talking about replacing the water. I'm talking about pumping it out of the pool and replacing it with 'fresh' water. Naturally I know it'll depend on what you throw into the pool and at which point the chemicals get unbalanced. Here's my current thoughts about this:

• 3" puck (~1ppm CYA PER PUCK)
  • Needs to be emptied once per season due to the high levels of CYA
• Cal hypo (~0.8ppm Calcium per pound)
  • Also once per Season.
• Liquid Chlorine (17ppm of salt per gallon)
  • For me that comes up to roughly 1'200 ppm/year. With copper pipes, I wouldn't generally want it to get too high. So I'm guessing maybe every 3 years would be worth replacing the water? Not sure on this one
• SWG
  • I could be wrong, but I'm not sure that an SWG adds much to the pool in terms of "forever" additives. Thoughts?
• Evaporation refill
  • My city claims that the water has a Calcium level of 25ppm. 132ppm for CaCO3 (Not sure if that factors or not). Assuming I want a range between 200-400ppm, I'd have to half of the water inside my pool every 8year to bring the calcium back to 200.

So it looks to me like going with an SWG would have me use the least amount of water. Did I miss anything here?

 

[Texas Splash]

An SWG is a very popular method of chlorinating the water. With he exception of the initial salt loaded to the water to help it generate free chlorine, nothing is added. But you may wish to bounce some of your numbers above with our PoolMath APP - the "Effects of Adding" section. For example, one chlorine tablet adds more than just 1 ppm of CYA. But that APP can give you much better numbers overall for planning purposes.

 

[Bperry]

There would be no reason to ever replace the water using a SWCG. Unless it got so contaminated with algae that it was cheaper to replace the water than use the chlorine needed to sanitize it. SWCG adds nothing to the water, though you need to add enough salt at the initial startup and may need to add small amounts over time. The amount of salt needed is nowhere near “salt water” that is found in the ocean.

If you’ve been using pool store advice to maintain your pool, following the TFP method should cure you of ever having to totally replace your water.

 

[Jimrahbe]

Chris,

The only two reasons to drain and replace any water in your pool is if your CYA or CH get too high.

I have three saltwater pools, and since I had them replastered, they all have the same water. One of them has had the same water for over 11 years, one over 9 years and one for about 8 years.

The idea that you need to routinely replace your water is just a silly myth.

Thanks,

Jim R.

 

[ti_chris]

An SWG is a very popular method of chlorinating the water. With he exception of the initial salt loaded to the water to help it generate free chlorine, nothing is added. But you may wish to bounce some of your numbers above with our PoolMath APP - the "Effects of Adding" section. For example, one chlorine tablet adds more than just 1 ppm of CYA. But that APP can give you much better numbers overall for planning purposes.

Oh that's awesome. I used the app, but didn't notice that it had the option to calculate all of the side-effects. Very cool. Thanks for the heads up.

There would be no reason to ever replace the water using a SWCG. Unless it got so contaminated with algae that it was cheaper to replace the water than use the chlorine needed to sanitize it. SWCG adds nothing to the water, though you need to add enough salt at the initial startup and may need to add small amounts over time. The amount of salt needed is nowhere near “salt water” that is found in the ocean.

If you’ve been using pool store advice to maintain your pool, following the TFP method should cure you of ever having to totally replace your water.

I'm already using TFP, but yes I see int he app now that SWG doesn't actually affect chemistry outside of what it's supposed to.

Chris,

The only two reasons to drain and replace any water in your pool is if your CYA or CH get too high.

I have three saltwater pools, and since I had them replastered, they all have the same water. One of them has had the same water for over 11 years, one over 9 years and one for about 8 years.

The idea that you need to routinely replace your water is just a silly myth.

Thanks,

Jim R.

My concern is for my copper pipes against the salt. If I don't drain, it'll constantly increase and will get ever more toxic & corrode the pipe. I'm currently using a Stenner pump with liquid chlorine, but my salt is closing in on 3k. At the current rate & if I never empty it, it'll reach ocean levels in less than ~25years. If I had abs pipes then perhaps that wouldn't be as much of an issue, but sooner or later, the salt will reach a highly corrosif level if left completely unchecked.

I wonder what liquid chlorine people do when they have copper pipes.

 

[Bperry]

Oh that's awesome. I used the app, but didn't notice that it had the option to calculate all of the side-effects. Very cool. Thanks for the heads up.


I'm already using TFP, but yes I see int he app now that SWG doesn't actually affect chemistry outside of what it's supposed to.


My concern is for my copper pipes against the salt. If I don't drain, it'll constantly increase and will get ever more toxic & corrode the pipe. I'm currently using a Stenner pump with liquid chlorine, but my salt is closing in on 3k. At the current rate & if I never empty it, it'll reach ocean levels in less than ~25years. If I had abs pipes then perhaps that wouldn't be as much of an issue, but sooner or later, the salt will reach a highly corrosif level if left completely unchecked.

I wonder what liquid chlorine people do when they have copper pipes.

The salt is increasing from the liquid chlorine stenner pump. Once you stop adding salt, no more salt will be added.

And 3000ppm of salt is about right for a SWCG.

 

[Oly]

I faced this issue buying my old pool, draining / refilling then using liquid chlorine after four years. Planning an install of my SWCG required a partial drain / refill to lower my salt level from 4500 to 3500ppm. No problem.