I'm goading Vaughn into a nice article like synopsis

That way we can arrive at some consensus about what to do.

Two vendors on both sides of the pond will sell the KH reference solution diluted down etc perhaps.

Using Bromothymol blue is the best alternative and the vendors should be able to get this in large amoutns as well as small 1 oz sizing as well.

You add 3 drops to 6mls of KH reference solution basically.

Regards,
Tom Barr