Want to measure K+ and do not like the junky test kits? These are pretty good and have good usable accuracy( about 0.5ppm) over the entire range and more at lower ranges under 10ppm. Comes with 2 curvettes and caps, instructions, easy to use for aquarist with straight forward instructions.

Hanna HI 93750 Potassium ISM. No reagents are included.
Low use(maybe 100 samples read), small, comes with a 9 volt battery, built in timer for reading the sample after reaction time.

Run about 190$ ea
HANNA Ion Specific Meters - Ben Meadows Company

Reagents are not cheap, about 90 cents per test but you can use the standard methods to DIY those for cheap.



130$ includes shipping

Regards,
Tom Barr

Hi Tom,

Sold! I'll take it. Please PM me with payment instructions........I just sent you an e-mail.

BTW, I was looking at the nitrite and nitrate meters on this link. Thoughts? Have not found a cheap HACH Dr980 colorimeter lol

Thanks.

Sold to Gerry!