a very different opinion.

this is the opposite of what I do, but a well meaning friend who I sometimes buy plants from wrote this today.

"I think you should put some aragonite in your filter and disconnect the CO2. You
need to increase the hardness and provide an alternative carbonate source. Do
that with the lighting you have and you won't believe the difference in plant
growth. CO2 is so misunderstood. It's a substitute for hardness more than
anything else, just a way to provide a carbonate source when it's not available in
the water. It's one of the main reasons I don't participate in any of those
discussion boards. Planted tanks have become techno junkie playthings. I think
most of the people who keep them any more are more into the gadgets than the
plants. Hard water, good lighting and plenty of iron fertiliser are all you need.
I'm getting off the soap box now!"

I somehow can't imagine my tonina's growing this way.. but I figured I'd let Tom chow down

 

why would some plants grow best in soft water? why can I grow all the tough toninas with a kh of less than 1? I know they suffer for lack of co2.. when mine went out they grew poorly and the fluviatiilus is only now recovering.

but don't they melt in a high kh tank?

ah or are you saying, that these are among the plants that would not make it in a kh run tank...

I am comfortable with co2 far more so than adding kh.. but it is what I know.