That sounds like a lot of water being changed. I would only do about a 10-15% water change if you are not having any problems.
Are you having any problems? Are your nitrates, phophates or other levels to high? If so, then do a couple of water changes a few days apart. I would only change out about 30% each time. To much of a change would stress the fish out to much, assuming that you have fish in there.
Again, it all depends on what if any problems you are having.
Let us know.