Underwater tripod for macro video (and video in general)

[Elvandar]

As in the title, I am searching for a tripod for my setup, for now I am evaluating 2 models from Joby:

1) The 5k model, that can support up to 4 kg and is made of aluminium
Gorillapod 5K Video Pro Kit per Video Professionali | JOBY

2)The 3k model, just the legs, that support up to 3kg but is made of plastic
 https://amzn.eu/d/1GGcgNu

I am more oriented on the 5k model, for sturdiness and his bigger weight capacity to be used also on land, but I don't know how well the metal will resist the salt water
For the 3k model, I fear that the less problem from corrosion, are balanced with a lighter construction and so easier to break

Someone have used them underwater? 
I saw only this post  on the forum, and not much more online, about using them underwater:

 

 

@waywardriley I try to tag you, have you tried the tripod in salt water? I saw that you used it only in the pool
Did it rust or had any problem?

My setup look like this, and I would add the tripod on the bottom:

 

 

I also saw the quad leg stabilization, but for now i think the tripod would better, being able to be folded away when not in use, and also cheaper (for the 5k I found a good used offer, and the 3k leg is around 40€)

 

Edited 19 hours ago by Elvandar