Well it only takes one or two quicksands to cripple a deck, as many only have 7 or 8 towers total. If they're restricted to playing one at a time, it's just not enough quanta.
Of course, then you remember supernova, and laugh at quicksands.
Basilisk blood, granite skin, congeal, and permafrost shield seems like enough slowing down. Nothing slows more than a permafrost shield, and a protected one at that. Nasty. Poseidon could stay, and is the best synergy water has with earth, but it might be too much.
Also, 8 is too many protect artifacts, especially as there are only 3 different permanents. Sure it guarantees that one is drawn early, but later they just clog up the hand, and a second turn protected Poseidon is the last thing anyone wants to play against. The deck has to serve its purpose, but it's not good if it's too hard.
For the name, I would try to find something that means "mud", but sounds more... less..simple. Like how Morte means "death". (I think.)