Flexibility in ratio?

Actually I think the 20 is the lowest you can go in the series. The ratio is 1:1 on all mixes and to get to 30 or 40 you would use 50 and 20 to bring it down to those two numbers but I haven't seen where you can go lower than 20. To get it softer than 20, you would have to experiment and I'm not sure how that would come out as I haven't tried that myself.

There isn't a softener for the Flex series, only for the Alumisol but I don't think that will work on the Flex.If you've done experiments with other products and they worked, I'd try some with the Flex too and let us know if they work on the Flex.