After eliminating all through hull fittings as the culprit in my persistent water leak, I tried adding some blue food die to the ballast tank. Subsequently finding blue tinted water in my bilge confirms a leak in the ballast tank. I can't find any imperfections in any visible part of the tank so I guess the next step is a borescope to try and find the exact location of the leak. Any thoughts on how to proceed? From my searching, I gather that there are not many options for actually fixing the tank if it ends up being under the cabin sole.