OK I found this in the Feb 2006 Tropical fish Hobbyist magazine....... Isn't this Dec 2005? Oh well.
This is from an artical from Jack Wardley on page 36 and 37 and I qoute....
"And while on the subject of water treatment I should explain how a private water treatment company made some interesting studies with water from my discus hatchery. This happened at a time when our local water treatment facility became two facilities, the results being that I had not established any connection with the new chemists in the water treatment plants.
I was interested in the amounts of toxic waste in my discus water in relation to the amounts and frequency of my water changes. I set up a 40 gallon tank with 20 discus, each 2 inches (5 cm) in size. Needless to say, I carefully monitored the feedings of the fish, as well as the water pH at all times.
We have to begin somewhere, so let's use the more or less standard once per week water change of 40 percent that many discus hobbyists have made. The results were interesting.
Changing 5.7 percent of the water each day (which means 40 percent weekly) indicated a toxic level of 20.6.
The twice weekly changes (each one 20 percent) resulted in a toxic level of 19.2,
and the once per week change of 40 percent resulted in a toxic level of 17.7.
The tests did indicate that, if one does not want to make a weekly water change of 40 percent, it's probably better to make the change all at once weekly rather than breaking it up into 20 percent changes twice a week or daily changes of 5.7 percent."
I think this is the answer we have been looking for.
This is from an artical from Jack Wardley on page 36 and 37 and I qoute....
"And while on the subject of water treatment I should explain how a private water treatment company made some interesting studies with water from my discus hatchery. This happened at a time when our local water treatment facility became two facilities, the results being that I had not established any connection with the new chemists in the water treatment plants.
I was interested in the amounts of toxic waste in my discus water in relation to the amounts and frequency of my water changes. I set up a 40 gallon tank with 20 discus, each 2 inches (5 cm) in size. Needless to say, I carefully monitored the feedings of the fish, as well as the water pH at all times.
We have to begin somewhere, so let's use the more or less standard once per week water change of 40 percent that many discus hobbyists have made. The results were interesting.
Changing 5.7 percent of the water each day (which means 40 percent weekly) indicated a toxic level of 20.6.
The twice weekly changes (each one 20 percent) resulted in a toxic level of 19.2,
and the once per week change of 40 percent resulted in a toxic level of 17.7.
The tests did indicate that, if one does not want to make a weekly water change of 40 percent, it's probably better to make the change all at once weekly rather than breaking it up into 20 percent changes twice a week or daily changes of 5.7 percent."
I think this is the answer we have been looking for.
