Float Ring

We tried to float down the river on this tube yesterday.  The valves do not work.  The internal air pressure spontaneously pushes the plug out which causes all the air to release.  In an hour of floating, it came undone 3 times.  Also, the valves are on the bottom which is a very poor design.  When it comes open, there is no way to quickly close it.  Don't buy this product.  Poorest design ever!!!!