Drinking water filters - when to change element?

[Andrew Mawson]

She who must be obeyed decreed that we had to have a drinking water filter tap by the main one - that was 8 months ago.

When I bought it I also bought a spare cartridge ("Spun wound polypropylene over activated carbon core"). Advice plastered all over the bumph that came with it demands it be changed at 6 monthly intervals and this is backed up by several letters and phone calls from the supplier pestering to sell another cartridge.

Now the flow through the filter appears to me to be just as it was when first installed - and there are no complaints about the taste / smell / colour of the water - and presumeably given that the capacity of the element is finite it's life will greatly depend on volume of water and concentration of contaminates which must widely vary from any 'norm'.

Surely end of life of these elements will be indicated by a reduced flow rate through the filter or a lack of ability to remove smells etc- or am I missing something here ?

If the chlorine smell came back or everyone was complaining of the taste I'd pop the spare element in straight away but at the moment I'm feeling that perhaps the endpoint is more determined by the suppliers cash flow issues than the actual element !

Anyone got any experience of the longevity of these filters?

Andrew Mawson

[John Rumm]

That is true - or more to the point that would probably indicate that the filter is past the end of its life. You really need to change it just before then! ;-)

Some of the filters include a metering capability that alerts you after a preset amount of water has been passed through it - that makes it pretty easy. If yours does not then I suppose you could try and monitor the water useage through it for a few days to work out an average usage per day. Then (if the manufacturer gives a quantity of water that each filter can handle) calculate a number of months it will take you to use that much....

[Martin]

polypropylene

The problem is the carbon, it has a habit of "load dumping" what it has absorbed when it can't take no more.

[The Natural Philosopher]

Used to use Brita filters. Changed em about every 18 months or when the thing they went in went green from algae.

Surprisngly effective.

[Grunff]

I don't think that can happen. In order to desorb stuff off the carbon, you'd have to change the conditions which initially led to the stuff being a_d_sorbed in the first place.

All that will happen is that the carbon will no longer have the capacity to adsorb your chlorine/other crap, and will be ineffective.

[usenet]

If you do a 'blind' test can anyone actually tell the difference between fitered and unfiltered water?

I suspect it may well be more placebo effect than filter! :-)

[Ronald]

Hi, I live in Scotland and do not use a filter and drink the water straight from the tap but when I visit my son in Newbury his water tastes terrible straight from the tap so I bought a filter jug and it does make a difference. I'm trying to persuade him to fit a filter for his water but he drinks bottled water(comes in brown bottles or cans) and since he lives alone he does not think the expense is justified. Ron

[Velvet]

Nope, not where I am. I can tell from the smell and the taste straight away if it's filtered water or not. Non-filtered water is disgusting here (north downs hills, surrey). Equally hard (if not harder) water in cambridge tastes fine straight out the tap.

I've done a 'blind' test (with help) and nailed the unfiltered straight away. Disgusting stuff.

Velvet

[Andrew Gabriel]

One issue is growth of bacteria in the cartridges, in the material they have filtered out. Commonly, silver in some form is used to limit this, and I believe that is the component which wears out, resulting in increased bacteria levels. Having said that, I always use my Brita cartidges for at least 3 months, 3 times longer than you're supposed to, and these have the same issue. The water softener and whatever removes the chlorine "swimming pool" smell from our tap water in them has never worn out on me, and I'm in a hard water area. My Brita filter is always kept in the fridge though, which may also help with limiting bacteria.

[Christian McArdle]

I'd remove the filter if it did.

Can you get fluoride dosing devices, like the phosphate ones? Presumably they could be dangerous if faulty and no-one wants the liability risk...

Christian.

[Christian McArdle]

It may also be the main help with the taste, rather than the filtering. Few people can detect the difference between filtered and unfiltered water after it is refrigerated, so you may not notice even if the filter has totally expired.

Christian.

[Andrew Gabriel]

Well where I am in North Hampshire, the difference is very obvious as the tap water has so much chlorine in it that it smells like a swimming bath, and that doesn't go by standing it in the fridge to cool (done that by accident when forgetting to but a new filter in the jug on a couple of occasions, and no one could miss it). Nowhere else I've lived had so much chlorine in the water -- this is the first place I've bothered to use a water filter.

The water softner part has certainly never worn out either -- no deposits form in the kettle which is always filled from the filter, and I'm in a hard water area.

[The Natural Philosopher]

Yes, definitely if you are in a high chalk high chlorine area. I am not sure they don't put in ion exchange resin pre-loded with sodium as well, otherwise I don't see how they get the chalk out - or teh chlorine.

Whether the small difference in taste is worth it tho, is another matter. I don't bother anymore.

I always got green slime before I got 'didn't do anything' on the Britas. They honestly lasted a year or so just filling the kettle, but every summer algal bloom got them, and so I used to drain, wash out with bleach, and refit new cartridges.

[BillR]

Too much flouride can cause unsightly marks on growing teeth.

[BillR]

This is what dissuaded swmbo from having a fixed tap cartridge system years ago. There was some info about germs building up in the cartridges and that idea went straight out the window...

[BillR]

I'm in the same area and I don't know why they have the cheek to charge for the water around here. It more like dilute limewash than water. Neighbours without water softener have had to replace HW cylinders twice in

20 years.

[Malcolm Stewart]

I'd prefer to be the judge of that, and I think I'm now old enough to know what's good for me.

[Adrian Sims]

No. Fluoride is highly toxic. I don't want it in my water and I NEVER use toothpaste containing fluoride. My dentist doesn't use it either. It causes inumerable problems. See fluoride.org.uk and many other references on the net.

I believe that there may be some chance of appealling to the European Court if the government force fluoride upon us forced "medication" is seen as a breech of human rights.

A.

[Grunff]

Nonsense.

Everything is toxic at the right dose. Oxygen is pretty toxic at high concentrations. Water will kill you if you drink enough of it.

As with anything, there are risks and benefits. If the benefits outweigh the risks, we do it. If not, we don't.

I'm not going to go into the detail here, because I can't be bothered - google will tell you all you need to know. The site you name above is the biggest pile of crap I've read this week (I read a lot of crap).

Yes. Make sure that foil hat is on tight.

[The Natural Philosopher]

Mmm. I don't see the connection, frankly. Unles you have spent a few years drinking both sorts of water, and one made you ill, and one did not, how can you tell?

Or its it the opposite of IMM 'its scientific sounding, so it must be right' but in youir case 'its scienctific fact, so it must be wrong'

Bear in mind that chlorine was intrioduced to water, without consulting anyone, to eliminate cholera from the poor, because mainly, it didn't stop there.

Let's say that drinking fluoride is a requirement of NHS dental treatment then.

You want choice, we can give you choice...