Dosing KCI

Question two:

I worked my way into the EI method of dosing by first knowing what my water had in it naturally. My fish food and feeding habits kept ample N and P in my water, but I had no known source of K. I first used KNO3 and KH2PO4 when I got the plants going well, but my measured level of PO4 went way up, like to 10ppm or higher. So I ordered up some KCI potash at the recommendation of other net denizens and have been dosing with that and KNO3 in various levels depending on my tank plant health.

Is there any other effect on my tank water from KCI that I need to monitor or watch out for?

thanks,
steve