Water Heaters - Hot Water Heater Help

I have a hot water heater that I'm having problems with. Basically started out with running out of hot water very quickly. I flushed it and found hardly any sediment. I replaced the element. (Only one bottom one on this heater). Still having issues so I replaced the thermestat. The termestat was a little bigger than the original one and did not snap in as solid but that is the only difference. The problem got better but I'm still no close to the hot water that I had. I have the temp turned up fairly high.

There isn't much to these things so I'm not sure what could be left. I would assume if the thermestat is not quite fitting right that the water would be hotter not colder.

Any thoughts would be appreciated.

If your heater is about 10 years old, you may have one of those defective dip tubes that fall apart.

I didn't see any parts in the bottom when I had the element out that looked like that but possibly. I don't think this heater is that old either. I guess that is my next best thing to change short of the whole heater.