Well It does sound like it is a good idea and price for the convenience. I wish I had a store that did that around were i live. But I do have to say it is much cheaper buying your own salts and miking it your self. I can make up 200 gallons of Tropic Marine Salts for less then $60.00 and I always have it on hand and to my specifications of salinity and add buffers if I want.