what worked for me is to create your own base, what ever color you want the water to be paint the bottom of the base one color darker (Ex if you want blue water paint the base navy blue.) then dry brush the color you want the water to be on the base. the purpose of this is to use the base as the color and leave the water effect clear.
after the base is painted construct the rest of the base. and you will push the water effect in the cracks let dry and pressto!