One BIG problem with this deck. Huge ongoing demand for earth quanta by lava golems, trident, and the two graboids. I played ~10 games with this deck (only difference was I used an upgraded otyugh), and in every game I ran into a shortage of earth mana. This is most prominent when you have a lava golem in play, a graboid in your hand, and a trident out, and only, for example, 3 earth quanta. Do you evolve the golem, play the graboid, or kill some of the enemy's pillars? Often it takes several turns to generate another 3 earth quanta. Since you're not garunteed earth mana every turn, or even in any number of turns (I went an entire game with almost no earth mana nearly all the time, it was the strangest thing to see all my other elements with 20-30 quanta and earth with less than 5 after I only used it to grow a lava golem once and use trident's ability.) Granted, this IS a rainbow deck, and is based on luck, but having two cards that use earth for their ability, especially when one requires 3 quanta, and then tacking on two cards that require 3 earth a piece to come into play is way over-taxing it.
otherwise, worked pretty well. Quit 3 top 50 matches against opponents that got out 5 shards and started playing shields, won the other 7, 2 with elemental mastery (both times opponent played an otyugh which I either froze or poisoned, or both.
Besides the problem with uneven quanta distribution, nice deck, great idea, I'll tweak it some and try it out later. peace.