dutchy101 If you are steaming 3 times a week, but drawing a cup of water for tea daily, you should be ok. As Rob said, you can keep an eye on GH and KH by drawing water from the service.
I test every month and steam on an average 1.25 - 1.5 times a day; these are my 8 months average of steaming 330 ml of milk each time. My average hardness reading is 11 mg/l to 16mg/l with an alkalinity reading of 40 mg/l to 50mg/l using the water drawn from the service boiler after steaming.
My routine after each steaming are :
- Immediately switch off the machine after steaming so the pump doesn’t kick in.
- Draw a cup after each steaming
- Switch the machine on so that the pump runs. Switch off the service boiler.
- We flush out the water from service boiler once a month.
Ours is also a Minima boiler. But, on the first 2 or 3 batches of Evo, the same minima boiler is set up a little differently. So, we can never flush out the water 100%. There will always be a third of the old water left in the service boiler. So, we have fitted a drain valve under the service boiler recently. I did see some traces of scales when I fitted the drain valve in Feb.
Since, I am drawing a cup after every steam, we believe the scaling potential is very much under control. There will be traces. Since Feb, we don’t add any bicarb. I just fill the remineralised RO.
@DavecUK did advise me that since we draw a cup of water after every steam, there is no need to flush the water out every month. He suggested may be once in 3 months as it is the remineralised RO.
Once our Osmio is returned from the workshop, as per Dave’s advice, we are going to pull out the Re-mineralisation catridge just for 4-6 weeks and feed the machine with pure RO to naturally get rid of any scales, which may have formed. Perhaps, we will do this every 6 months, pending an anniversary inspection.