hanna

hello, i just got a new TDS-3 meter, it was factory calibrated to a NaCl 342 ppm... I bought a Hanna instruments 1500 ppm TDS solution So my meter only shows 3 digit numbers, how do I read my water levels if its 4 digits? do i just multiply by 2 or what? This is pretty confusing, plus how...

Anyone used these?