If the machine is as prescribed in the instructions firmly screwed on a countertop, the water tank can be removed or installed. A water change is therefore not possible without the machine from the plate unscrew what they must be partially disassembled.
The lateral guide rail, even when the screws are tightened with all my strength to be moved with the little finger. On a straight cut is out of the question. A little remedy is the application of fabric tape on the side edges.
Since the other tile cutter in this price region have striking similarities with this, is probably assume that they are all the same China scrap manufacturers come and all of them are useless. Can only give a recommendation, better to spend the money for the rent of a professional machine.