From what I see it looks like your team is weak to starmie big time. Instead of having tentacruel, you could add blissey to help you counter starmie with. Here is the set i would use:
Blissey @ Leftovers
Ability: Natural Cure
EVs: 252 hp, 252 def, 4 spD
Nature: Bold
- Seismic Toss
- Softboiled...