I can't remember what my kh is, but it is pretty high since I live in N. Florida and use well water. I have had problems with stunting if i don't dose enough as well as the algae. I am especially having troubles in my 55g with crypts where I don't dose ferts or co2, but rather put in fert tabs. The bba is coming back but not too bad as long as I do WC. I have pressurized co2 for my 10g and 20g, and I still have bba popping up even though in the 10g it seems to be dying and growing at the same time. I can grow Ludwigia repens, but that is common in Florida. I am growing Rotala mini type 2 very well as well as indica. I haven't tried growing anything too difficult yet. I have noticed that aqua soil amazonia softens the water, but I tried amazonia 1 and it is leaching tannins into the water, while amazonia 2 does nothing to the water color. Then again the ada site says thats what amazonia 2 is for hard water, but it disintegrates too easily.
These problems probably have to deal with the excess Ca in our water and not enough other nutrients to allow the plants to uptake the excess Ca.
These problems probably have to deal with the excess Ca in our water and not enough other nutrients to allow the plants to uptake the excess Ca.