When I had my saltwater setup and the fish had ich I wanted to treat them so I ended up dying the caulk in my 20 gallon blue. I have gotten out of saltwater for now and want that 20 gallon for a small freshwater system so I decided to re-caulk it. I would have to say that it was not hard at all. I did take a couple of pictures because I know how everyone likes them even if it is only caulk and glass seams. The type of caulk I used was a simple 100% silicone from Lowes. it was pretty simple and i did end up using regular masking tape for the seams that would be seen that really made a nice edge.