10-17-2002, 12:07 AM
:? IF the levels in the tank are fine then why do we have to do water changes?

Also I'm running a emperor and a mag 350 both with bio-wheels on a 120 gal tank is this enough? Also I don't run any air into the tank as I figured the surface is moved enough by these 2 filters am I right in thinking this?

10-17-2002, 09:33 AM
SGM would probably be able to give a better, more detailed answer, but here I go. The filters will only remove so much waste. Imagine living in the water with your own filth, the filters might be doing a great job, but it's not likely to keep it clean enough to stay healthy. When you pull out the old water, you're also pulling out some freefloating nasties which you replace with good, clean water that only has the nasties your water board put into it (like chlorine/choramine/flouride).

It's kind of like being in an air conditioned building with never getting any fresh air.

You're aeration is fine with the filters you mentioned. You don't need an airstone. I just keep them around for emergencies like water is too warm or the filter breaks and I can't get one until tomorrow.

10-17-2002, 09:37 AM
i think that jonah's answer is perfect--we are able to measure some of the water's parameters--the most crucial ones--but think of all the other stuff that is builiding up that we can't measure. also--minerals are depleted and need to be restored with fresh water.

10-17-2002, 09:47 AM
Thanks SGM, I thought about the mineral thing too, but since everyone's water supplies are different I wasn't sure how big a deal that would be.

10-17-2002, 05:53 PM
:) Thanks for the reply.