Check your test expiration dates.

[Sk8r]

Well to mark these in heavy black marker when you get a test. You can go some really bad places if you start chasing results from an expired test kit.

And after 2020 and the pressures of 2021, don't let old kits be your problem.

 

[boxfishpooalot]

Yes salifert potassium test expired 2018 was 370ppm and a new one 420ppm. Dont trust expired kits.

 

[Sk8r]

chasing a bad test result in the belief it's the one Truth and everything else is lying to you can kill a tank. No kidding.

 

[Timfish]

I would also add store reagents properly as heat can age them and to test new test kits or reagents against old kits or reagents.

 

[mhurley]

chasing a bad test result in the belief it's the one Truth and everything else is lying to you can kill a tank. No kidding.

I almost did this in the last couple months. Was chasing alkalinity from a Salifert kit that was not expired, but was close. Long story short, test said it was 7dkh and dropped to 5 over a weeks time, as I was boosting soda ash input.
Got the Hanna digital one and whoops, alk was now 12.