CO2 test kit recommendations

George Booth wrote:

>If you use a good CO2 test kit, accuracy is around 1-3 ppm.  If you
>measure pH and KH and use a table, the accuracy depends on the
>accuracy of the two test kits and the granularity of the table. 

George makes a good argument for the limited accuracy of estimating
CO2 concentrations by interpolating from KH/pH tables.  So I suppose I 
will have to invest in *another* test kit.  What kits are recommended? 
Joanne (I think) mentioned the LaMotte kit. Is there any consensus about