i tryed one a few months back. i tought it might be cool to be able to look at the little thing and know everything was n check. after 1 week i threw it out. it was saying my tank was a 6.8 when i was at 8.2(Ph pen i got free from work) it was made for SW, not the FW version so i thought it would work. cost me $25.00 w/shipping. glad i didnt buy the whole kit. it came with:
Nh3
Ph
No2
No3
thought it would be nice but not for $100.00 and its not even accurate. imo stay away from them. for FW they work great. my GF's lil bro uses them and they are dead on the money