A few question about RO

[Billsid]

Hello everybody ,

I have a few questions about RO systems in general ...

1) mineral or calcite filters : which one is better as post treatment ? Or should i use both ? I've seen various mineral post cartidges containing small rocks etc and some calcite filters containing calcite from Imerys company (which is NSF certified product - standard 60 , i think).These post filters should be placed after the RO membrane or after the collecting tank ?

2) Are there any chemicals to sanitize both the RO system and the RO membrane ? I 've seen a method to sanitize the system by using household bleach but this procedure doesn't cover the RO membrane itself.Let's say i am going on vacations for a month ...what should i do when i get back home , in regards to RO System sanitation due to this prolonged period of inactivity ?

Many thanks ,
Bill

[Andy CWS]

What is your objective in applying post cartridges (not filters btw) after the RO?

All those ROCK drinking water systems do extremely little. I visited a house that had a three gallon tank in the kitchen half filled with stones and the homeowner said their salesman told them that this wilol put minerals back in the water. Cost them about $350.00!!! Yicks! I tested the pH before and after....not a trace of difference.

Calcite mineral cartridges can raise pH slightly but other conditions must be present in order for it to work. But my question is what is your goal in doing this? If these work, your water will taste similar to hard water with a slight chalky after-taste.

Always put the cartridge on the line leading to your water dispensers.

Andy Christensen

[Billsid]

Hello and many thanks for your reply ,

My feed water has a TDS value of 140 ppm , therefore the RO water is around 3-4 ppm . I would like to raise it a bit (let's say around 20-25 ppm) , thus improving the taste (now it is quite flat).

A friend suggested that i should use a ''mixing valve'' but i am not sure what this is exactly (is this used to blend RO water with pre-filtered tap water in order to achieve the desired TDS value ?) Are these valves sold as accessories and can they be retrofitted to my unit ? (i have a standard 5 stage RO system with booster pump - Filmtec inside)

A salesman suggested that it would be better to use a nanofiltration element instead RO ...there is this GE Osmonics nanofiltration membrane that fits inside standard 1812 RO housings and it only reduces the TDS by 50% (so in my case , i would get a TDS value around 70 ppm , which is the ''ideal water'' (that's the salesman claim )

Finally , any ideas in regards to the sanitation procedure would be highly appreciated

Thanks ,
Bill