I have a 5 gal tank for my single betta fish and I cant get test strips and kits out where I live because of import duty and things and I havent found anyone carrying the local brand ones. People are telling me to do a 50 percent every week and this boggles me. One single fish in this much water and I need to be doing 50 percent a week? Just wanted a second opinion. ask questions if u need more clarity and I will answer them! thanks!