As someone who has been maintaining a pool for several years, you really hope you don't have to cycle the full amount of water once a year. You're really doing something wrong or incredibly unlucky if that's the case. That's at least true for the climate I live in. If I lived in a different climate, I'd probably forego having a pool.
It was incredibly painful when I had to drain the pool for deep maintenance a few years ago, and I'm not looking forward to having to do it again in a little while.
Also, most residential pool owners don't have half olympic pools in their yard. They're usually much smaller than that.
> Also, most residential pool owners don't have half olympic pools in their yard. They're usually much smaller than that.
Hence my caveat at the end. When talking about swimming pools, tiny residential pools is certainly not what springs to mind for me.
Most pools near me are in fitness centres etc. and are 25m pools.
And I certainly wouldn't go swimming in one of those if the water wasn't cycled regularly. Thankfully the data suggest they are.
If we're talking tiny little residential pools, then using a swimming pool worth of water isn't very shocking. Unless I'm way off, a 10-15m shower every day would use a similar amount of water in that case.
> I certainly wouldn't go swimming in one of the water wasn't cycled regularly
Once again speaking as someone who has maintained pools for a while, if the water was properly monitored and maintained I probably wouldn't mind. I'd absolutely take a pool that's actively properly maintained but hasn't had a full replacement in a few years over one that's poorly maintained but was fully drained and refilled a couple of months ago.
From experience while my son was swimming competitively, they had to drain most of the pools he swam in completely more than once a year because of various contamination, in addition to the ongoing cycling...
I can't imagine the state they'd be in after a year.
Once again, if its monitored and maintained properly, sure why not? Partial cycling when things that can't be filtered get too high (like TDS or CYA for an outdoor pool) but otherwise make sure sanitization is happening properly, pH and other metrics stay balanced, and good filtering is happening, I don't see a problem.
> more than once a year because of various contamination
Sounds like that falls into the "unlucky" category.
If its that you don't like thinking about tons of other bodies have touched that water you're swimming in, remember that dinosaurs pooped in much of the water you're drinking today.
> Partial cycling when things that can't be filtered get too high (like TDS or CYA for an outdoor pool)
Partial cycling in a high traffic environment seems like it is clearly ending up being a lot of water when every number I can find suggests it is generally expected to add up to several times the total pool volume per year.
> Sounds like that falls into the "unlucky" category.
To me it feels like it falls in the "expected" category somewhere that is dealing with hundreds of swimmers including small children every day.
Keeping in mind this was across dozens of pools - he swam competitively, not a one-off or rare occurrence in a pool or two.
It seems like we're mixing up terms here and miscommunicating. I thought we were talking about actually replacing the water here (as in, down the drain, fresh water from the tap), not just filtering as in recycling water through filtration systems. The total volume of the water should go through filters every few hours. I'm 100% not for the idea of only "partial filtering".
> To me it feels like it falls in the "expected" category somewhere that is dealing with hundreds of swimmers including small children every day.
Nah, that is definitely not normal to have to completely replace the water multiple times in a year because of water contamination events happening. The water can usually be sanitized. It might require a day's worth of hyperchloronation, but not often an entire drain and fill. That will happen often, probably several times a year. Usually only if your CYA is too high will it require you to actually drain a significant volume of water, which I agreed was one of the reasons to at least do a partial drain and really only applies to outdoor pools. Doing a hyperchloronation will likely increase your TDS, which won't go down until you drain those contaminates. But usually you can get those numbers back in an acceptable range without having to drain and fill the whole pool.
If the pool was properly maintained, what state do you expect the water to be in after a year without a total drain and fill? Do you have experience actually maintaining a pool?
> It seems like we're mixing up terms here and miscommunicating. I thought we were talking about actually replacing the water here (as in, down the drain, fresh water from the tap)
We are. I changed it while you were writing.
Everything I'm seeing suggests typical loss to backwash of the filters for a short course pool is in the 5k - 10k liters of water a day range, possibly less if you invest in expensive additional filters. 5k a day is ~1.8 million liters a year.
To get below a full replacement every year for a small short-course pool, you need to lose less than 1370 liters a day, or ~1.4 m^3
You're shifting things from normally needing to fully drain and fill the pool multiple times a year from specific contamination events to now talking about routine backwashing events, which I agree do happen as a part of normal routine maintenance (a part of the "partial drain" and "good filtering" I was talking about before).
I agree you'd probably use something like 5-10k liters of water for a backflush for filters that size, but that wouldn't normally be a daily thing. The amounts needed here would be highly variable depending on a wide range of factors.
I still stand by if you're having to actually fully drain and refill your pool multiple times a year (as in, an actual drain and fill, not slow partial replacement from weekly/every other week filter flushes) you're either very unlucky or you don't know what you're doing maintaining the pool.
It was incredibly painful when I had to drain the pool for deep maintenance a few years ago, and I'm not looking forward to having to do it again in a little while.
Also, most residential pool owners don't have half olympic pools in their yard. They're usually much smaller than that.