What method should i use in order to remove moisture from air of a container completely? Should i flush it with N2 or argon (its air-tight) or is there a device that i could use to remove moisture from the container? The container is prone to condensation due to extremely low temperatures. I need that water out :D
The de-facto standard way of getting all the water out of a cyrostat before cooling it is to pump it out with a vacuum pump, then back-fill with dry gas from a cylinder. Nitrogen is cheap and easy, helium is preferred if the cryostat will be cooled below -190C (but I guess "extremely low temperatures" probably isn't that low). Depending on the achievable pressure with the vacuum pump and how strict the requirement is, you might pump and flush more than once.
If the requirement is not as strict, it may be enough to blow out the air with dry gas without pumping down to a vacuum first.
If you want to get rid of a small amount of water after purging, or take up moisture seeping in through a leak, you can use silica desiccant. It's dirt cheap, but has limited capacity. When it's full, it can be dried out in an oven and used again. It's the same stuff that you get in little "do not eat" bags with clothes and goods, but you can buy it in big containers too.