Underwater Filming for a Movie

Hey! Quick question for those of you who do filming with your tail. I'm working on a mermaid movie, but I have a lack of underwater shots due to the murky water where I live. It's perfectly clean and safe to swim in, but because it's Connecticut, you can't see anything underwater. I've been able to get exactly zero good underwater shots, even though I have a great camera for the job. Is there a way to rig a pool (maybe with a weighted sheet back drop or something) to kind of look like the open lake (no fish needed, empty water aside from the mermaids is fine) without looking totally fake? What do you guys do? I don't have the option to CGI, though I can do color grading, and as far as I know, there aren't any tanks available for rent. I'm about to call an aquarium and ask if we can shoot in a tank for a day! (Just kidding.) Any tips or advice you guys might have used before?

Fist and foremost, for filming, any venue you use will want insurance, and any public space you use will want permits. Even if it's a public space, permits are needed - even for short films (I have starred in a few along with commercials)

You actually can call aquariums and some will rent them out for filming provided you have insurance, any applicable permits, and hire a safety diver.

There are also industrial pools used for training that can be rented out for filming and are usually used for big productions as well. With the right lighting and a basic backdrop, you can look like you're outside in a lake or ocean very easily. This is the case in my city, I did a whole video about filming for a movie at one of these facilities here: https://www.youtube.com/watch?v=muvJ_T25iHQ

Travel may be your best shot, we did some of my shots for one of my films in the springs in Florida because they were crystal clear. It really wasn't that an expensive a trip using online booking agencies.