

I have just set up a new tank, and let the water stabalize for 3 weeks.
This is my setup:
90L Tank
2 Ehiem Aqua Balls
PH 7.5
Temp 25 degrees celcius
KH - 8 deg. dH
GH - 10 deg. dH
NO2 - < 0.3
O2 - 8
NH3NH4 - 0
Fish
5 - Neon Tetras
5 - Guppys
To treat the water, I used:
Tetra Easy Balance
Nutrafin Waste Control
Proper PH 6.5
As soon as I put the fish in they looked very unhappy. After 4 hours one guppy was dead and all the others had lost there colour, and look sedated at the bottom of the tank, only swimming along the pebbles.
Does anybody have any ideas what might be happening?
Thanks in advance.