Welcome to TFP NanaMarie!
If I understand correctly: you had a sand filter last year, you replaced it with another and you transferred the sand from the old to the new?
Before you head to the pool store, put on your skepticism hat. If you don't have one, a few thousand of us here on TFP could you lend one! Also guard your wallet. What often happens is your water is tested in a haphazard manner and the results are used to sell you a bunch of un-necessary and overpriced products.
Our approach is to do our own quality testing at home using one or two recommended kits and add only what our pools actually need. The kits we recommend are the Taylor K2006C and the TF-100. I'm also a big fan of the SpeedStir, which makes testing the water easier and frankly more fun.