[QUOTE=Ray;920435
RO water tastes nasty, so those cartridges pass it over calcite.[/QUOTE]
I think that depends on what you're starting with... I have a little RO unit under the sink, I end up with a TDS of 15-20 PPM, nothing but the usual sediment and carbon filters, and the water tastes great... what comes out of the tap untreated tastes like chalk. So the "feedstock" is loaded with calcium carbonate, and Kvet has a similar composition - that's southern California. If the RO system takes the TDS closer to zero, maybe it's tasteless and flat. But starting with liquid rocks, I'd doubt that any more calcium needs to be added.

Tastes nasty? That's the first time I've read that, but value your opinion because of your reputation here. I don't trust all the "salesmen" RO websites that make it seem like RO is the solution to all of life's problems (I heard alcohol is, but, I don't drink).

In my last home, when I was quite into the coffee hobby, I used a calcite filter after the Mavea filter, in order to bring the pH back to neutral (the mavea results in water pH ~6.5). I did blind comparisons, and, surprisingly that pH had a discernible effect on the coffee taste. Nowadays I don't care, I've moved on. Would something like this work? Pentek GS-10CAL/RO-B Inline Filter - GAC/Calcite Sale $9.99

Would I use straight RO for coffee/tea, or after the calcite filter? Maybe I'll need to do taste tests again :roll:

Okay. Can the tank be wall/ceiling mounted? I'm happy to share pictures of the space if you/anyone is curious.

I can probably always retrofit the kit. I'm still a little leary of this, and, they recommend minimum 25ft distance for the re-injection. The water heater is in the basement, right next to where I will install the RO - so I guess I could tubing to either end of the room and make a long run maybe even a design to make it artsy fartsy.

Got it, thank you :)

---------- Post added at 02:15 PM ---------- Previous post was at 02:06 PM ----------

My tap water TDS is moderately high - 440ppm, and the mavea filter doesn't do much to reduce that. Fortunately, water in my area is super cheap here, and combined with the expired existing filter makes it an opportune time to do this. On the other hand, electricity here is 2-3 times the neighboring communities' :((

I always use the RO water for coffee and tea...don't want to scale up the coffee maker or tea kettle. Probably improves flavor too, but evaporation from hot water definitely leaves nasty deposits when using tap water.

The "nastiness" depends on the amount of air exposure.

Pure RO has no taste and has a pH of 7. Upon exposure to the air, carbon dioxide starts dissolving into it and dissociating, forming carbonic acid (H2CO3). It is a weak acid, but it makes the water taste sour...."nasty".