This is Red Seatest kit I have.
Please do tell about low and high range testing. I did not know it was possible with this kit if it is.
Is there another kit I can get Nitrates further dialed in?
I have the master kit, but I believe they are all same. For low range, you use 16ml of water. For high range, 1 ml of tank water and 15ml of RODI water. Reading is multiplied by 16. so if you get 1ppm on low range, it's 16 on high range.