Please HELP my African Clawed Frog!!!!!

[Dejavudoo]

Thanks for all your condolences. I'm devastated. Some people might say "Its just a frog", but I've cried like a big baby over my little Bibbit. I also feel really bad for Freckles since he lost the only friend he's ever known. As much as it hurts, I will have to get him a new friend; at least after making sure that Freckles is in good health.
He has some kind of sore near his eye. *sigh* So he is in an isolation tank now being treated with tetracycline. I just don't understand what's going on with my aquarium. I feel like such a horrible mommy.
I've tested my water, everything is fine except the water hardness is at about 150 GH. I have large gravel as substrate, two pieces of driftwood, and two plants ( a java fern and an anubias). What's also frustrating is that even the anubias is dying and its suppose to be a hardy plant! I have an underwater fluval that I turn off at night. What in the world could be going wrong?

[Jenste]

you are never supposed to turn your filters off for any extended period of time (pretty much only the few minutes you need for a water change to prevent the motor from burning out) - - without water and oxygen moving through the filter, the bacteria colony dies - - in short, you are keeping your tank forever in a semi-cycled state.

[Dejavudoo]

Yikes. I didn't know that.

I know you have a colony of froggies. What kind of filter do you use?