Water tests while using medication

[Aquarium Girl]

I used Promethyasul for the first time 10 days ago and fish are looking healthy and happy. I changed about 70% of the water 3 days ago but it's still tinged green.

I'm about to do another 50% PWC and put carbon into the filter.

Just wondering if it's worth testing the water? Are water tests still accurate with medication in the water?

 

[aqua_chem]

What's the primary ingredients in that med? I don't think that there are any medications that will interfere with the test itself, but depending on the shading you might not be able to read it well. It all comes down to how dyed the water is and how good your eyeballs are.

 

[Aquarium Girl]

It's a malachite green base but most of the med has been removed from the water. Was just wondering if it would change the chemical reaction and give false readings so thanks