Posted: Fri Dec 02, 2005 9:01 pm
Yes, Eva was/is doing 50% once per month and 4x25% would be a slight improvement. Water change math can be somewhat coning for some folks though and your post provided a great opportunity to point out RTRs excellent article on the subject.
A lightly loaded tank could certainly get by with less than 50% PWC per week in many cases, especially if we only consider pollution caused by fish waste and overfeeding. Municipal water contains lots of chemicals, minerals and trace elements though. Evaporation will result in concentration of many of these pollutants (for lack of a better term). Since we cannot easily determine people's water chemistry, bio-load, filtration, tank maintenance and feeding habits from the limited information provided in most posts, we will almost always recommend that they follow the safest course of action and do frequent 50% PWCs.
A lightly loaded tank could certainly get by with less than 50% PWC per week in many cases, especially if we only consider pollution caused by fish waste and overfeeding. Municipal water contains lots of chemicals, minerals and trace elements though. Evaporation will result in concentration of many of these pollutants (for lack of a better term). Since we cannot easily determine people's water chemistry, bio-load, filtration, tank maintenance and feeding habits from the limited information provided in most posts, we will almost always recommend that they follow the safest course of action and do frequent 50% PWCs.