Two Questions!

[quantumnerd]

I know that filter companies will always shout at you to buy their stuff. Like, really buy their stuff. As in change the filter media more than you need to.

I'm running an undergravel filter, With the discardable media being two "discard-a-stones" as air diffusers, and two *proprietary* (I haven't figured out how to gut and refill them) carbon cartriges.

How often to I need to change the stuff? The box says once every two weeks. That seems awfully expensive, and unnecessary.


For question number two, I see a lot of fish in fish shops. Strangely, a lot seem to have white bellies for no apparent reason. (eg: sunset platys and cardinal tetras at a certain store have had white bellies).

Is this simply fixable discoloration, permanent discoloration, a non harmful but annoying disease, or a bad case of illness?

 

[drobbyb]

To answer your first question, you really do not need to run carbon unless you are removing meds. It's expensive to run it all the time since the actual usefulness lasts for a few days, not 2 weeks.

I'm not sure about the second answer so hopefully someone will come along with more experience with them than I.

 

[quantumnerd]

Thanks! What about air diffusers though? do I need to replace them, cause they'll get gummed up or something?

(still awaiting answer about white bellies on non-naturally white bellied fish)

 

[drobbyb]

The air diffusers need replacing periodically as they tend to start to disentigrate. I haven't used one of those in a long time though. Big bubbles move more water than lots of tiny ones. That's why you don't use an air diffuser with a sponge filter.