Planted Tank Guru
Join Date: Jun 2004
Location: Baton Rouge, LA
I rely more on biological filtration than water changes for overstock conditions.
For example, let's say I have three inches of fish per gallon in a 10g, which is 3x the normal guideline. First, I provide filtration suitable for 20g instead of 10g, and sometimes even more. Then I also pack the tank with fast growing plants, and provide them what they need to grow rapidly.
Together, the filters and plants will very effectively clean the water between 50% weekly water changes.
I only do more than one water change per week if there's a known issue, for example:
* A filter has failed.
* I've done a rescape and stirred up a lot of detritus.
* Something has happened to the plants and they're no longer in peak health.
* A fish has died and I didn't notice in time, or was unable to locate the corpse.
* The water is cloudy, indicating a bacterial bloom from poor conditions.
* A water test indicates any ammonia or nitrite.
* I've feeding a type or quantity of food that fouls the water (common when I'm raising fry).