As Greech said, at this point, it is no big issue. Personally, I would wait until I got the sump you mentioned you were getting because it will add more water to total volume. drain everything, don;t worry abot the sand, and premix salt water to fill tank and sump. Tap water will be okay for initial fill since after cycling you will be draining most of it out prior to adding livestock. read the sticky on cycling. I personally am a fan of a raw shrimp in a nylon method. The longest it has taken me to cycle using this method is 10 days.