Quote Originally Posted by headshake
you don't usually need calmag+ for tap water. as rusty stated, calmag+ (and similar supplements) are for reverse osmosis water/distilled water. tap water usually has these things in it.


-shake
In RO and distilled it most definitely is a requirement.
I've always found though that for the rate which we force these plants through their cycles the demands are usually very similar when using tap water in a hydroponic or soilless medium. Some genetics will be able to push through without a cal-mag supplement but many won't, remember also just because you don't see the deficiency... doesn't mean it isn't happening!

Cocogro from Botanicare is pre rinsed with CalMag+
It's a great medium :hippy: