Total chlorine and Combined chlorine are not the same thing. TC is the sum of the FC plus the CC. FC is the chlorine that is available to sanitize the water. CC is the chlorine that has already been "used up" sanitizing something in the water. TC is the total chlorine. You want CC to be 0, BTW and therefore, you want your FC to be equal to your TC. (That is kind of a simplified version of each.)

Kind of funny that that online pool store ran out of kits. (Not funny if you are someone waiting for yours, however. ) What do you bet that Pool Forum had something to do with that lack of available kits! Somebody should tell them they have us to thank for their good business and how about a donation to PF!