Water calculator: Scaling potential and Remineralisation

dfk41

MediumRoastSteam I looked at Zero Water recently when I was having problems and one of the main differences I could see between the old and new products was the insistence of changing the filters every 30 days. I dislike this sort of advice as you may go on a 28 day holiday so why change the filter?

I bought a bloody expensive Phillips Sonic toothbrush. I had it replaced 3 times because after charging the orange light was flashing. I spoke at length with customer services who were very helpful. Eventually it turned out, that the toothbrush heads have a chip in that does this every 3 months, whether you have used the toothbrush or not.

I have had 2 RO machines. An Osmio and a Waterdop. I am a simple soul. I want to put tap water in and press a button and get RO water out. I do not care about anything else. Waterdrop do dynamic pricing meaning the unit price jumps all over the place. With a bit of care I bought a K19 unit for £243 delivered. It is a single filter machine. it is fast and quite efficient to me. The replacement cartridge is around £70 and if your TDS is ok you can reset the warning light.

I find having unlimited RO water on tap because the methodology is so easy, I drink a lot more water. I do not re-mineralise (but that is not to say I should not). My Evo leva had RO water for 4 years and showed no signs of problems with the internals. I cannot really understand why folksplay around with water jugs but as always, each to his or her own.

Legendofthejive

dfk41 Are you happy with the K19 unit? How often do you find you need to change the filter and what is your water hardness like? How much water do you tend to get through on a weekly basis with it? I will be using the zero water jug until the 12 filters run out but I think I will be looking at other options if the zero water filters stay as they are price wise at Lakeland. I am also considering some of the RO countertop options that include heated water. We got rid of our kettle some time ago and have a hot water dispenser, but with water hardness in the 300’s it loves to scale!

MWJB

dfk41 I looked at Zero Water recently when I was having problems and one of the main differences I could see between the old and new products was the insistence of changing the filters every 30 days. I dislike this sort of advice as you may go on a 28 day holiday so why change the filter?

I think there is a European standard dictating that jug filter cartridges be changed every month, it is up to you whether you feel the need to comply - with regular use, I was using the same Zero filter for up to 3 months as long as reading less than 006TDS, bearing in mind that the water was always going to be sterilised by heating before use (never drunk cold).

Many filters/systems do not recommend using filters that have been left dormant for 2 weeks, or more. As, once used, bacteria can build up internally. Filters are consumables.

dfk41

Legendofthejive My tap water has a TDS of around 110, so pretty low. Once through the machine, it is around 10. I reckon I fill the water reservoir at least once a day, sometimes twice. The Elizabeth egst at least 750 mls a day. My cartridges do not have to work very hard. I think the first machine I had I delayed the change over to 15 months as the TDS was fine but Dave said what about stuff living in the filter so I changed it. As I said, at 68 I am not remotely bothered about consumption of microplastics. If the world was really that bothered about them they would ban them but I cannot see that happening somehow.

It does produce hot water. If you stick a probe into the waterflow after a few seconds it is around 85. I know tea is supposed to be made with boiling water but how many make their cuppa then immediately start to drink it? I have amde tea from the hot water but on the whole I still use the kettle as it has a one cup option

Legendofthejive

dfk41 Thanks. Our water hardness is a fair bit higher. It will be interesting to see how the zero water filters do once I start to use them later this month. If I can replace the hot water dispenser with an RO that produces water hot enough for our tastes then there will be room for the K19 or similar. We aren’t massive tea drinkers so hopefully it may do.

MediumRoastSteam

dfk41 My tap water has a TDS of around 110, so pretty low.

If I measure my tap water TDS (not hardness) then it’s 180ppm. Hardness is 310ppm. In my brain it doesn’t make any sense why the TDS is lower than the actual hardness - but I just accept it’s true as I cross-checked with multiple sources.

Inspector

When i changed my osmios filters last time they were over 2 years old and a bit :)

MWJB

MediumRoastSteam This is very unusual, though TDS and total hardness can be equal.

One reason (most likely) could be because there are 3 different TDS ppm scales based on which conductivity correlation your TDS meter uses. Your water supplier is very unlikely to provide a TDS mg/L, or ppm (same thing) value and more likely to provide conductivity in microsiemens per cm.

Another factor could be the total hardness is not described as ‘mg/L as ion’, like it would be on a bottle of water. ‘Total hardness’ is expressed ‘as CaCO3’, this is the industry standard.

So, you multiply the calcium as ion by 2.5

You multiply the magnesium as ion by 4.1

…then add them together. If your calcium was 82mg/L and your magnesium 25mg/L as ion, you’d have a total hardness of 310ppm. But, I’d expect a higher TDS than 180ppm here.

Lastly if you live by the sea, there might be seawater ingress into the aquifer, this pushes the bicarbonate content very high, compared to the hardness.

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