unheard

What do you mean by "lock up"? Do you have a link? You can read more about chlorine and CYA in the Richard Falk's white paper: https://cdn2.hubspot.net/hubfs/3831534/Chlorine-CYA.pdf "This is why 3 ppm FC with 30 ppm CYA is the same as 6 ppm FC with 60 ppm CYA is the same as 10 ppm FC with 100 ppm CYA. As the CYA level climbs, the FC must also be increased proportionately in order for the hypochlorous acid concentration to remain constant."

actually the levels of chlorine in drinking water can also be as high as 5 ppm, according to this infographic:

Over 50 ppm, like what.... 120 ppm? 60, 70, 80 and even 90 ppm are all within an acceptable range for the hot and sunny climate, as long as you keep your free chlorine levels at 6 or 7. And no, 6 ppm of chlorine is not a "horribly high" level to have in your pool. For a comparison, some drinking water contains as high as 4 ppm (high limit).

Yes, the higher levels of CYA, the lesser the ability of free chlorine to oxidize "things", thus the need for increased chlorine levels in order to keep the water always properly sanitized. But that's not the point. The point being is that in the Thailand's hot and sunny (especially in dry season) climate there's no way to keep chlorine in the water unless there's significant level of CYA present. Sunlight is super efficient at destroying chlorine in the water, virtually instantly if there's no CYA added. The reason for the recommended 60 ppm of CYA or more is to allow free chlorine to stay in the water long enough to do its job. My understanding is that in Europe and the UK in particular, there's simply no need for the higher CYA levels due to sunlight being not nearly as strong as in the tropics (UV content), plus the cloudy weather is much more prevalent throughout the year. In addition, it doesn't make sense to discuss CYA levels without taking into the consideration other factors, like indoor vs outdoor. There's no need for higher CYA levels in the indoor poos, or even outdoor pools that are sufficiently shaded from sunlight.

Very much surprised to hear about such a low CYA number, especially considering the Australian climate (big sections having it hot and sunny). It's super difficult to keep sufficient levels of chlorine in the water with readings below 50 ppm of CYA (quickly destroyed by sunlight).

Here are tables from the U.S. based TFP forums. They always stress out the importance of testing your pool water chemistry. Since you can only determine the needed free chlorine levels based on your specific water chemistry and the installed chlorine delivery system. e.g. for a Salt Water Generator equipped pool:

I've never been to Lake Tahoe!! It's always been on my short list of places to visit but then Covid hit. Oh, well. ???? Regarding the water quality in streams and lakes. You might want to look into science behind "Natural Swimming Pools", based on the same principle of self-cleaning properties as in natural lakes or mountain streams.

REDUCES CHLORINE CHEMICAL USE Powerful oxidation reduces the amount of chlorine needed to maintain a safe residual in the pool, saving you time & money whilst protecting the environment. Still works in conjunction with chlorination?

I've asked you to please share some info on those "modern systems". And the following question would be, then why in the world anyone continue to use the "clumsy, hard-to-manage chlorination" if those new systems can do everything better and "save effort and money"? I've mentioned a few newer technologies that are well known and readily available for purchase, yet somehow just about every private pool owner everywhere in the world continues to use chlorine as a main disinfectant.

Can you please elaborate on those? I'm not aware of any new tech that can safely and economically displace chlorine as the main disinfectant besides UV, Ozone and Oxygen that might sound cool and sexy but the underlying problem is that neither provides an easily controlled and/or economical disinfectant solution , comparable to chlorine in convenience and cost.

I think you're mixing two different things. Do you lick your door knobs at every opportunity? Do you eat your meat/fish dishes raw? Do you prefer to drink untreated/unfiltered water? You might get away with practicing such a diet for a while... Until it hits you. Here's a much more relevant question: what is your precise pool water chemistry readings? You won't know unless you test it with a high quality pool water testing kit, on the regular bases. And if you don't know for sure, what else, beside you, is swimming in your pool, then the only solution is to maintain an appropriate level of free chlorine. You might say: why to worry, I'm the only user.. How do you know who or what might invite itself for a little swim into your pool in the middle of the night?... Some day...

I'm sorry, but the only duties the car manufacturers serve are to their shareholders. I, as anyone else, do respect and actually admire the honest and competent work of any, not just a pool, professional that takes pride of his/her work. Unfortunately the world is full of the fly-by pros, especially in the pool maintenance business!!! And you, as an honest Pro (I suspect), are surely aware of many such examples. Otherwise there would not be no need for a huge online forum (U.S. based) which is full of testimonies of many, many pool owners (new members are still sighing up and then sharing their stories)whose pools have been systematically neglected by the small and BIG U.S. based thus government regulated pool maintenance companies. Check out for yourself: https://www.troublefreepool.com/forums/

What would be your response to Bagwain's claims that the Zelbrite media retains biofilms, as opposed to the glass media?

Can you provide any proof other than your own claims? And no, sale brochures or producer's ads can not be considered as a proof!

Thanks for the info! It's really hard to navigate through all the marketing noise.

Can you elaborate more on Zelbrite and why it's better? There's no much of the real world usage feedback to be found.

"I want to replace my pool sand filter with AFM Glass Filter." Do you have access to AFM in Thailand?? AFM is indeed an amazing water filtering media. https://www.drydenaqua.com/files/pools/resources/pdf/test_results/IFTS_Report_E_Print.pdf And quality sand is still not far behind at water filtration - sand beats every other glass media except AFM.

And you obviously failed to understand or just chose to ignore the results of the test. AFM is the only glass media, out of five others, that was capable to best sand. The other five were shown to be inferior. Besides, can you tell us where in Thailand you can buy AFM, what is its cost and how many customers of yours have been benefiting from it? AFM is a completely different beast and has nothing to do with the heavily promoted by you EcoClear. And it's not being advertised as such (similaraty to AFM) in your sale brochures. EcoClear is just a "normal" glass media very similar to other 5 inferior glass medias presented in the test.

Most of the glass media is shown to be inferior compared to quality sand in both filtering and backwashing tests (test date: 2014) https://www.drydenaqua.com/files/pools/resources/pdf/test_results/IFTS_Report_E_Print.pdf

Astral doesn't seem to be anything special as glass media. And according to the test below doesn't filter as good as sand (filtration velocity: 20m/h)

Commercial and domestic work on the same principles but in vastly different configuration setups, with different priorities. Private and commercial pools can not be easily compared.

Backwashing is related to the process of removal of trapped solid or semi-solid particles suspended in the filtering media. Backwashing requires a generally much higher water flow/pressure condition allowing the media to raise and expand, as to allow the suspended particles to dislodge from the filtering media. But the angular media won't allow to achieve the same rates of the media raise/expansion as compared to a more rounded media due to the shape of the particles, thus preventing full flushing. Glass media companies usually claim that they provide better filtration, and bio-film build-up resistance. Are there any tests to prove that (better filtration in particular)? I've seen one such test that shows otherwise - glass media providing worse than sand filtration properties.

??? I don't think I get your point. I have specifically mentioned back washing since the angular media doesn't allow the proper implementation of the process.

"What is the best sand media for a Emaux filtration unit please?" The following looks like a reasonably priced quality silica sand: https://www.winwinpoolshop.com/en/product/15004-11286/silica-sand-25-kgbag As for the best filtration media? The following product seems to be clicking all the right boxes, at least judging by the provided info. Don't know anything about its price or availability. https://www.waterco.com.au/pool-spa/filter-media/glass-pearls

And what's your experience with backwashing? Even the linked brochure mentions the ecoglass' media high angularity which would be a huge impediment to proper backwashing - the angular properties of the glass don't allow the media to be lifted by the flow of the water which leads to reduced media expansion which in turn prevents proper cleaning. The sand particles don't have that problem (being well rounded in comparison).