Plumbing

I recently bought a used Skimmer from ReefCentral. The skimmer body is leaking from the bottom. See this picture:



After doing some online digging, it appears that the best option I have now is to get weld-on #16 and apply it around where the body meets the base. I want to make sure that whatever I do, I dont want to worry about this leak again in the future. Any ideas ...

The sedra pump on the ASM G3 skimmer is not starting. I removed the skimmer to clean. When I put it back first it ran fine. I stopped to adjust the skimmer placement. I am starting it again it is not starting at all. Any ideas?