I got a new tetratec ex1200 4 days ago. i've put it in with one of my established internal filters, even put some old filter floss and bio balls in the new filter, washed the new pads in tank water etc. the last 3 days ive had to do 2 massive 90% water changes as i had an ammonia reading of 0.50ppm and then today it was between 0.25ppm and 0.50ppm. so i'm sat here soaking wet with the floor flooded after filling and emptying about 20 buckets and i had to net 2 dead fish out of the tank 
i honestly don't know what i did wrong, my water was perfect before the new filter. i was runnning 2 internals and left one in to run with the ex1200.
i honestly don't know what i did wrong, my water was perfect before the new filter. i was runnning 2 internals and left one in to run with the ex1200.
