Flattening a Bunched up Watermattress, aka; Fibershift

In my 25+ years of performing waterbed service, perhaps the most common problem encountered by the do-it-yourselfer that I have been most often been called to fix, is the bunching up of the fiber matrix inside a waveless watermattress due to improper handling after being drained, also know as fibershift. While some manufacturers internally tether the fiber to the mattress to prevent this from happening, most do not because it requires extra seams to do so, adding expense and vulnurability. After all, the seams and valve are what is covered under warranty, so the less seams, the better. Most hardside and softside waterbed mattresses have a free floating fiber pad inside, requiring a minimum of seams. What is key to preventing this from happening is achieving a vacuum inside the mattress, which will occur naturally when draining, either with a fill and drain kit, siphoning, or a waterbed pump. Before you start draining, be sure to remove all air bubbles through the open valve with a broomstick, after unplugging the waterbed heater. This will insure that a vacuum will occur as it drains. When the flow of water slows to a light trickle, remove the hose from the mattress and immediately repace it with the plug and cap, or you will lose the vacuum and the mattress will fill back up with air. When the mattress is full of air, the fiber pad can easily shift and bunch up into a ball and twist. Do not remove the plug and cap untill you are ready to fill it back up. The ensuing vacuum, when maintained, will make your waveless mattress easy to fold and handle, and less "blobby". If it gets puffy, it means either the cap is loose, or it has a leak. If your fiber does shift, the best way to flatten it out is to use a wet-vac. The water must first be evacuated as much as possible. First, using a wet-vac, blow air into the mattress through the valve opening. As the air inside begins to compress, turn the vac off and look inside the valve to see how the fiber is shifted. It is helpful to have the room sunlit, or as bright as possible, as the vinyl is opaque. Try to find a corner or two of the fiber and work it into a corner of the mattress. this will probably take some time, and you may need to blow it back up again as necessary with air to see inside the open valve. When you get a corner of fiber into a corner of the mattress, grasp them together and elevate as high as you can, allowing the fiber pad to unfold. Kind of like the way you make your bed up. This will allow the fiber to flatten, just like a comforter. Repeat as necessary until fiber is visually flat. Next reverse the air flow of the wet vac, (after removing the filter) and suck as much air out of the mattress as is possible, and immediately plug the valve. Do not remove the plug until you are ready with your connected hose to refill it. Any ridges or buckles in the fiber will usually work themselves out as you refill your waterbed.