The truth about test strips is that as soon as they come into contact with air ie. pop the seal they degrade. I always use salifert test kits for trace elements and doc wells or tetra for Nitrates, nitrites ans Am. So yes they are completely inaccurate.
I hate say it but I go to petsmart for doc wells. As for the sulifert about 18.99 to 27.99 can't rember having a bad case of crs tonight I will check for you tommarow.
i test with strips every week but test with the good tests every other week. the strips are easier and faster IMO, but if they show that somthing is off i retest with the other. basicly i use both to double check
because i am cheap and won't order test strips online so i have to drive two hours to get to where i buy them. plus alot of time i just want some reasurance that everything is okay before i go to bed/school/work/out and don't have alot of time