HI GUYS I HAVE A 31IN , 14.5 GAL TANK WHICH I'VE HAD SET UP FOR JUST OVER A WEEK NOW, I PURCHASED SOME FISH FOR THE TANK ON FRIDAY AND SINCE THEN ONE OF THEM HAS DIED EVERYDAY INCLUDING ANOTHER ONE TODAY MAKING IT A TOTAL OF 3 OUT OF THE 18 GUPPIES THAT I PURCHASED. IN ADDITION TO THE GUPPIES I ALSO PURCHASED 2 DWARF FROGS AND 2 CLOWN LOACHES WHICH SEEM TO BE FINE. I HAVE A 8" AIR BLOCK WITH AN AIRVOLUTION 200 PUMP WHICH IS OXYGINATING THE TANK AND AN EHIM ECCO FILTER WHICH I HAD RUNNING IN THE TANK WITH PLANTS ONE WEEK BEFORE I BOUGHT MY FISH. I TESTED THE WATER YESTERDAY AND AMMONIA LEVELS WERE AT 0.25 (2ND FROM THE LOWEST) AND THE NO2 LEVELS WERE HIGH WITH THE NO3 LEVELS IN THE MIDDLE OF THE CHART. I SPOKE TO THE PEOPLE WHERE I BOUGHT MY FISH AND TANK AND THEY ADVISED ME TO CARRY OUT A WATER CHANGE TO HELP REDUCE THE LEVELS OF NO2 AND AMMONIA I DID A 10% WATER CHANGE YESTERDAY AND YET TODAY ANOTHER FISH DIED. I'M NOW UNSURE WHAT TO DO SHALL I CHANGE MORE OF THE WATER TODAY OR IS THERE SOMETHING ELSE I CAN DO ? 