I have a sick betta in a 2.5 gallon. Not quite sure what's wrong, but I'm trying Jungle Fungus Cure powder packets. Each packet treats 10 gallons, so I did my best to divide it into 4 for 2.5 gallons. I want to lower the water level down and put just 1 gallon of water in the tank. Can I premix the Jungle and do the 2nd dose after 48 hours? Or should I just do 1 gallons worth and throw out the rest? I don't want to waste it but also don't think I can accurately split powder into 10 groups.