K2SO4 and PMDD

Just got the chelated micronutrient mix today and I'm almost ready to mix 
up a batch of PMDD.  I'm only missing the ingredients that give the K.  Can 
KCl be substituted for K2SO4?  If so, what is the correct ratio?

Rochelle Williams
williaro at ftmcphsn-emh1_army.mil
Now where did I put that 2 liter coke bottle?