what is ideal sulfate levels for planted aquaria?

I've recently eliminated adding nitrate to my aquarium since my fish are
growing bigger and there is enough supplied naturally. For my macros I used
to add potassium nitrate, potassium sulfate, and phosphate. Now I'm only
adding potassium sulfate in double the quantity that I used to in order make
up for the loss of added potassium that I was getting from the KNO3. Since
I'm doubling that dose (to get approx. 20ppm potassium) I'm realizing that
the amount of sulfate added is also doubling. Would this pose a problem? I
don't know how much sulfate is required or neccessary in a planted aquaria
and didn't see it listed in Chuck Gadd's pmdd calculator.

Thanx for any help!!

Dave Picklyk.