Not if your only doing water changes. Do not touch your filter or your gravel bed just take out and replace water. Add your water conditioner, prime is my choice.
Keep a close eye on the ray. Though I am sure a healthy ray will handle the changes fine I have heard that they can be rather sensitive to the chemicals in tap water. Since I know its not likely you will have enough pretreated water to do all those water changes on a tank that size filling the tank slowly and adding the water conditioner prior to filling will be a good idea. When I first got my Motoro I quarantined him in a 75 for a month or so before adding him to my main tank. I had a 55 gallon tank I kept filtrated, heated and full to do daily changes on the tank. I found it to work great. The filters had a chance to develop BB and I had the ability to push fresh water into the tank daily without worrying about the possibility of the chemicals having any effect on my ray. I got my ray from Pedro and he was the one who told me to use the pretreated water and I will say that my ray was and still is healthy as could be.
