The test strips are age and heat sensitive, so make sure your test strips are not out of date or stored in a hot area. You should only take the coolant, to be tested, from the radiator, using the petcock, at the bottom.
Dip the strip in the coolant for 1 second.
Shake briskly to remove excess liquid.
Wait 45 seconds before reading results and no longer then 75 seconds.
I have some bottles of the SCA additive. I check my coolant before changing the filter, so far it has read in the normal range so I order the 4 unit filter. This still keeps it in the normal range. If I were to get a low reading, in between filter changes, I would add one of the 4oz. bottles of SCA and recheck once I drove the MH.
All the instructions and the color chart should be with your test strips.
Tom, Pat and Buster (the Boston terrier)
2004 DSDP 3807, 370HP Spartan