also massively snipped and mid-posted

I am having trouble locating chemicals of this nature.

I found 2 pounds of lab grade KNO3 on Ebay fairly cheap and I had no
problems recieving it via UPS...
I've been using "NO SALT" from the grocery store as a source of potassium...
And for phosphates I use Fleet enema also from the grocery store...
ymmv but these are working ok in my 75.

Well... actually, I was hoping to eventually avoid such massive water
changes. ;-) Is this possible once things get going?

Everything I have read indicates that the large water changes are nesasary
to maintain the balance and replenish some of the trace elements etc...

Thanks again for the advice.

Greg