So I have noticed a lot of post about Summoner DPS rotations yet I have not seen this.
Basically I noticed that you can clip a RUIN II after any spell with a cast time. So this is what I do.

BIO II>RUIN II>MIASMA>RUIN II>BIO>THUNDER>RUIN II

By now I have all my dots up, my pet has used contagion and my dots are lasting forever. I normally weave between FESTER and ENERGY DRAIN then repeat as necessary.

I realize I am not lvl 50 and things may change then however I find adding in those free RUIN II's to add quite a bit of damage and a free blind is always good