NEED HELP STAT!

Hi ,
I am up to purchase New Phosphate (PO4) and Nitrate (NO3) test kit.

I got three kind of product on line:

Hanna:
Hanna Pocket Photometer Phosphate
Hanna Phosphate Photometer Low Range
Hanna Checker Nitrite Ultra Low Range

Elso:
Elos Phosphate Kit.
Elos Nitrate (NO3) Kit.

LaMotte:
LaMotte Low Range Nitrate Test Kit
LaMotte Phosphate Test Kit.

Which one do you recommend me to buy ...