Isn't it a bugger when you get something on your mind that keeps you awake at night. However that's sometimes just what I need. I have given much thought to the problem in my sleep and I think I have something of an answer to it.
I know that a cup of coffee leaves calcium residue in my cup, the rim of the fishtanks has a line of calcium from the evaporation, and the kettle has loads on the heater elements.
Given that, I wondered if boiling the water would reduce the readings for hardness etc.
I have now got out of bed and used the water still in the kettle from last night and tested it. WOW.......
What a difference. The pH is much the same but KH has dropped from 19 to 8 and the GH has gone from 20 to 10.
Can someone else carry out the same tests to see if they get similar results please.
Next thing I'm doing is buying bottled water and testing that to compare.
RO would be ideal however I don't want any unit plumbed in so that all the household water is filtered. So much waste with that. I have an external tap on the kitchen wall that I would be able to adapt for a unit if needed but I'll see what the boiled water solution is like first.
And, yes the Chilli Rasboras will probably be the answer as I know them from the past. I already have CPD's in a single species tank, also with the hard water so I'm going to change over to boiled water for them too. It looks like a larger water boiler might be better than a RO unit.
Oh, and another thing. Boiling the water takes out all the chlorine I believe.
And yet another thing. Bugger me, I'm wide awake now and my head is buzzing with ideas based on the boiled water tests. If these can be verified, and I'm about to do another test after my last kettleful of water has cooled, then even a water boiler may not be needed. I have a couple of 56ltr plastic tubs spare that I could perhaps get a freestanding electric boiling element to use in one of them, if anyone knows of such a creature.