Getting higher TDS water than I put in the machine

Petre

It looks like the water I get from my machine has a higher measured tds than the one I put in, even after a good flush.

The machine is a dual boiler Silvia Pro, 1.5 y old. I use to run with Volvic then switched to custom water, BH#4 80gh 40kh for which my TDS meter reads 113ppm 🤷. I ran with this water for many months now.

Yesterday I switched to a different water recipe, the meter reads 90ppm.

I flushed with the new water about 2L through the machine only to read 100 ppm at minimum(water in the tank measures 90)

Today I flushed about 100ml, took a sample that measures 110ppm.

All the measurements were done with the water cooled off at room temp.

I just can’t make sense of this. Could it be that I have scale deposits into my boiler that contaminates the fresh water I put in?

Rob1

Petre did you get the water from the group or the hot water tap?

Cuprajake

Could do,

Put some really low tds water through for a week and see if it drops down

Petre

LMSC will try - got any recommendations?

Rob1 I got it from the group head, after some flushing.

Cuprajake I know - I was thinking even a descaling, I don’t mind taking the boiler apart, but was curious if I can understand what happens.

LMSC

Drop kit to measure GH and KH over a sample of at least 20 ml of water.

DavecUK

Petre I got it from the group head, after some flushing.

Group head is fed by a brass boiler isn’t it?

Petre

DavecUK indeed, this is how it looks like

Rob1

Likely water left over from the previous formulation that hasn’t been fully flushed out. With the brew boiler you’re only mixing the new water with the old water so it’s a process of dilution.

Volvic will have produced a bit of scale too, but very little of this will be dissolved back into the water as the solubility is very low. You’ll also probably get a very small increase in TDS from the boiler material.

LMSC

API GH & KH TEST KIT Freshwater Aquarium Water Test Kit 1-Count

https://amzn.eu/d/7cn5O86