Water in the cockpit!

The manual for my Ventus C states that there are 5 holes in the fin which holds up to 5 liters of water. You tape up one less hole than the liters you want. for example, if you want 3 liters, you tape up the bottom two holes.

Now the problem. My Ventus C has 6 holes. More capacity? different version or fill scheme? If any one knows, please help.

This just in; cockpit doubles as bathtub. I flew with water today, and at the end of the flight there was an inch or two of water in the forward foot well where the battery goes. This is surprising as water is not plumbed into the fuselage. There is simply an auto connected dump valve at the wing root. I assume there is a lot more water under the seat pan at the moment. Thoughts?

Thanks

Matt H