Hi all,

Maybe I should describe in details how the setup in my fountain pond.

I'm using a 24" x 12" x 6" black fibre glass tank which is actually meant
for an indoor fountain. Both my wife and me actually intended only
to setup an indoor fountain but decided that adding ranchus in it will
liven up our pond. Currently the right side of the tank is occupied by a
square fountain with water flow overhead down into the tank. At the left
bottom is my submiserble pump with a sponge filter. There's also a layer
of gravel at the bottom of our fountain pond. Each gravel measures about
1.5cm.
However, the water gets smelly on the fourth day after the fishes have been added. I'm changing my water every week (10%). I've been told to add rough salt into the water during every change. The smell condition
still exist. How should I solve this problem?

Thx & regards,
Kcaand