Im currently in the proccess of setting up my tank and of course i need to buy some test kits. I decided to check out a local website similar to Facebook marketplace and found a guy selling a slightly used API MASTER saltwater test kit (ph, ammonia, nitrite, nitrate) for a quarter of the original price. I am tempted to buy it but i am afraid that the test kits have expired. He bought them a year ago and used them a few times only. On the box, it says the expiry date is in 2022. Should I go ahead and buy it? Or would it be expired and give me wrong results? Thanks.