I'm looking for an INTROUVABLE and little-known film or series (DVD) dating from between 1995 and 2010.

I'm looking for a movie or series from between 1995 and 2010. I know the main character was a girl (teenager or maybe young adult), the other characters were also human. It took place entirely underwater (the whole series), and I remember there were cars, like a sort of camper van, which was red or green (I think) with hippie-style flowers (it was a bit like the film/series mascot).

I had it on DVD and I'm sure it wasn't famous, it was for kids, all the scenes were done with a green background, in my memories it was humorous and musical. It looked very "cheap"

In my opinion, it wasn't French (I’m French), maybe Autraslian, American, Québécois... (they were typical European characters).

I watched it when I was a kid (I'm a 2004), I don't think it came out before 2000, but you never know...

It’s impossible to find, I'd so much like to find this film / this series, I've done a lot of research but I've got 0 leads, I can't find ANYTHING. But what's for sure is that I had it on dvd, so you could buy it in stores (knowing that internet orders must not have been very frequent more than 10 years ago).