Has Anbody Used Ammo Lock

ive used it for 1 week and did a waterchange yesterday. today i cheked ammoinia and it said it was 8
PPM !!! i jumped up and ran to the tank and did a fifty percen waterchange 2 hours ago. then i just tested it and it said 8 PPM. i read the bottle and itsays that it does not get rid of ammo it converts it to a non toxic form. it will still test positive on your
test kit. BUT my hemichromis lifalilis ( Red Forest Jewels ) have lost there couler the last three days. my temp is 26
nitrite = 0 ppm,
nitrate = 10 ppm and
pH = 6.5 ... what could be wrong ? i feed blood worms, hikari cichlid gold, flakes, earthworms, and cucumber. thanks for any help