Ok so I set up a new 5 gallon tank about 2 weeks ago for my betta. I started the tank using Tetra Safe Start. I think its time for a water change. I have a gravel vacume and 2 gallons of distilled water. Whats the best way to do a water change? Should i dechlorinate the water first and wait for 2r hours and add more safe start? Can i leave the fish in the tank? Please help me. I ordered a test kit and it should be here in a few days. Do i need to wait?