Dosing 375mg Tetracycline per 24 hours to 15 gallons for 6 days,how much water should I change daily?

Question

Don't worry about filtering that's not relevent.

I just need to know how much water to replace purely to reduce levels of toxicity that may be caused by a build up of the Tetracycline over the dosage period of 6 days.

Answer 1

Regular water change of 25%.  This is to be done prior to each application.

Were you treating for ulcers?  

Remember no more than 10 days at a time or it could lead to anemia in your fish