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Old 15-06-2017, 10:37 PM   #106
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Join Date: Jun 2001
Posts: 56,181
Ramster is correct. Water with very low TDS is not really good for you and your kids over the very long term. That is esp if your diet is sucky to begin with with insufficient calcium/magnesium mainly (there are other things like bicarbonates in the water.....just google it up). We do not have many nanofiltration devices in the market (only saw some Haier stuff using that) but RO is not uncommon, some pax i guess could even be using distillers. The WHO article he posted says it all.

Ultrafiltration is fine, that's the 0.01 microns stuff. Their pore size cannot remove ions in the water. Basically just filters your bacteria and most viruses, which would be handled by boiling. Anyway they are not a big concern with PUB water.

Anyway, it's mentioned that we have desalinated and Newater (RO water basically) here in SG, which has close to zero TDS. But don't worry, PUB mixes it with our regular treated reservoir water before pumping to our homes, usually we get like 40-80 ppm TDS in our homes.

4) Filtration ability for the lifetime of the filter. If they claim 3000 litres, I would want to know the quality of my water after 3000 litres. When used beyond the recommended range, some filters start to dirty your water by releasing the contaminants in the filter back into your water, making it worse than without a filter. I like to be safe from the 1st to the last drop. If a company is good, they should dare publish the results after 3000 litres not just when the filter is brand new.
This is a good question. In case anyone is wondering, if it's NSF-53 certified for say lead, mercury etc @ 99% for 100 gallons, you can be sure that it does that. Coz NSF-53 have a very good buffer margin to allow for many factors like manufacturing variances.
The USA NSF certification is legit, really not "anyhow" one. And it costs the companies quite a fair bit of $$$ to test, so usually the smaller companies serving smaller markets usually do not try to attain that NSF certification.
And their big brands can do just that, coz the USA water filter/treatment market is worth well over USD 10 billion annually now.

2. When NSF rates capacity – how many gallons the filter is “good” for – it means that after the rated number of gallons the filter is still able to remove 200% (twice as much) of all the claimed contaminants. That doesn’t mean that the filter is only good for that amount of water. It means that according to NSF testing protocol, after the stated number of gallons passes though the filter, it begins to lose its capacity to take out twice as much as claimed of that one contaminant that presents the greatest challenge.

3. Just because a contaminant isn’t NSF-certified for reduction does not mean that the contaminant is not taken out. Manufacturers know, for example, that the same filtration media used to reduce VOCs works for THMs. VOC reduction is actually harder to achieve, so a company may elect to pay NSF only for the tougher VOC certification on the valid assumption that the product is just as effective (if not more so) against THMs.

The public generally doesn’t know this, of course. So in New York City, for instance, where the water supply almost always has THMs but never VOCs, a filter listed for NSF-certified VOC (but not THM) reduction really means that you are getting both.

4. Why do we use the word “reduction” instead of “removal”? Because NSF doesn’t like “remove” – they use “reduce”. We want to comply with their terms. And technically, they are right. Taking contaminants out of water is always about probabilities, percentages. Nothing can be assured 100%. Whether it says “removes 99.99%” or “reduces by 99.99%” doesn’t matter. Both mean the same thing.
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