Oh, go ahead and name names there, Logos. We have lots of Lee Filters in this country. And users can always go here for conversions, for the unofficial color media of the Control Booth! (but what's up with no #00, Clear?)
OK I always like L131 Marine Blue and for a more saturated sea green L116 medium blue green. When I can get it I also use L725 Old Steel Blue and L132 Medium Blue. This is for the above mentioned water effects you understand. I sometimes add a diffusion gel to soften the edges of the effect.