Oh WOW. I love the use of the grate as a detail in that big pool. Excellent use of image there. I think my only recommendation - and this is minor - would be to soften the layers of blue in your big pool at the bottom left of the map. We know that it's representing various depths of water but if it were up to me I might soften the boundaries just a bit.

Mucho cool.

Question of preference: Do you make numbered and unnumbered versions of your maps? Something for the GM to keep track of what room the party is in and then another for the party?

Great work.

-GP