Confused if my water is hard or soft. is someone able to help me clear up my confusion?

Got a Profitec Pro 600 and trying to minimize or all together avoid descaling.

Pictures of KH/GH test from water from my dispenser, kettle after 14 months use, water dispenser filters


The pics in the link are from the inside of my Fellow Stagg. I've used it pretty close to daily for 14 months now without ever being cleaned out. I did the API KG & GH test on water from my filtered dispenser and being conservative the KH changed after 4 drop so (4x17.9) +-~71.6ppm and GH a whopping 7 drops (7x17.9) +-~125.3ppm. According to the results I feel like I should have seen scale build up on my kettle by now? is 71.6ppm KH not considered hard?

I'm trying to figure out if my water is fine, or if i should do a 50/50 with RO water.

Results (did the '(+-)~' cause i think read its not exactly n# drops)
my 3 stage including a nano filter
KH - 4 drops to yellow (4x17.9) = (+-)~71.6ppm KH
GH - 7 drops to green (7x17.9) = (+-)~125.3ppm GH

Just RO from my parents dispenser resulted in
KH - 1 drops to yellow (1x17.9) = (+-)~17.9ppm KH
GH - 1 drops to green (1x17.9) =(+-)~17.9ppm GH

50/50 with my dispenser and my parents RO dispenser resulted in
KH - 2 drops to yellow (2x17.9) = (+-)~35.8ppm KH
GH - 4 drops to green (4x17.9) = (+-)~71.6ppm GH

Tacobae wrote:According to the results I feel like I should have seen scale build up on my kettle by now? is 71.6ppm KH not considered hard?

I think you meant to say 76.1 ppm GH. That's not very hard .


Geeking out and doing a rough LSI calculation at 76 ppm calcium hardness and 36 ppm alkalinity (as CaCO3), and at 100 ℃ (sea level boiling point) and pHeq of 6.8, you get a negative LSI of -0.04. Some of your hardness is probably magnesium so it's probably lower. A negative LSI tells you that limescale is more likely to dissolve than deposit.

P.S.
To learn about LSI clculations: Jim Schulman's Insanely Long Water FAQ.

homeburrero wrote:I think you meant to say 76.1 ppm GH. That's not very hard .

Wait, the water I've been using is not the 50/50. That's what I planned to use. For my kettle I've been using

my 3 stage including a nano filter
KH - 4 drops to yellow (4x17.9) = (+-)~71.6ppm KH
GH - 7 drops to green (7x17.9) = (+-)~125.3ppm GH

Maybe my Calc is wrong...

homeburrero wrote: Geeking out and doing a rough LSI calculation at 76 ppm calcium hardness and 36 ppm alkalinity (as CaCO3), and at 100 ℃ (sea level boiling point) and pHeq of 6.8, you get a negative LSI of -0.04. Some of your hardness is probably magnesium so it's probably lower. A negative LSI tells you that limescale is more likely to dissolve than deposit.

Well sounds attractive to mix my filter water with RO then...

May be worth explaining a little about GH and KH here.

The GH kit gives you a measure of general hardness or total hardness. Total hardness is the sum of the calcium hardness and the magnesium hardness.

KH in these kits is a measure of alkalinity. In most natural water, where the GH is greater than the alkalinity, the alkalinity is the same as the carbonate hardness.

The likelihood of limescale deposits is dependent on both the calcium hardness and the alkalinity, and is especially dependent on the water temperature. Water that doesn't scale in a kettle may be scale prone in the higher temperature of an espresso boiler.

That would make it non-scaling, But for kettles, you don't need to worry much about limescale because it's so easy to see if you have scale and easy to descale them if/when needed.

homeburrero wrote:
The likelihood of limescale deposits is dependent on both the calcium hardness and the alkalinity, and is especially dependent on the water temperature. Water that doesn't scale in a kettle may be scale prone in the higher temperature of an espresso Boiler.

That would make it non-scaling, But for kettles, you don't need to worry much about limescale because it's so easy to see if you have scale and easy to descale them if/when needed.

First off Homeburrero you are an honorable person! Thanks for the detailed explanations.

To sum up, would you say I should avoid my water dispenser water and go with the 50/50 mix with my water and RO? If I want to avoid scaling and the need to descale?

After rereading your initial post I got it get clear in my head that you have a Stagg, but are worried about scale in a Profitec 600.

The fact that you get no scale in the Stagg even with dispenser water is good, but it still may scale in your Profitec. With the 50/50 RO water, scale risk in the Profitec would be much lower, and right about what is typically recommended for espresso machine use, although not guaranteed to be non-scaling.

One fairly easy way to get non-corrosive and non-scaling water for use in your espresso machine would be to just spike your RO with some bicarbonate. No worries about limescale, or other undesirables (like chloride) that may be in your tap water. See Easiest way to make rpavlis water?

homeburrero wrote: One fairly easy way to get non-corrosive and non-scaling water for use in your espresso machine would be to just spike your RO with some bicarbonate. No worries about limescale, or other undesirables (like chloride) that may be in your tap water. See Easiest way to make rpavlis water?

Think I'll just go rpvalis at this point. Seems easy enough. 10g potassium bicarbonate per 1L of RO

I think I go brain dead at night... It's 0.1g potassium bicarbonate per 1L of water.... Right?

Tacobae wrote:It's 0.1g potassium bicarbonate per 1L of water.... Right?

Yes