If you have a softsided waterbed mattress there is a good chance it is filled with waterbed tubes, alternately it may be filled with a bladder. It is a straightforward procedure to check which type of inner your soft side bed has.
Simply unzip or flip off the quilted top. Inside you should see a foam cavity or rails, the water bag inside this cavity is a bladder alternately you may have a series of tubes. You may also have a vinyl safety liner and heater under the quilted top.
If you have a series of tubes your in luck. There are benefits to having tubes in your mattress. The bed is easier to move as tubes are generally easier to fill and empty. Tubes can be filled individually so you or your partner can set different comfort levels for different sides of the bed and in the event of a problem with a leak any damage is only likely to occur in one tube so your problems or potential damage caused by a leak is limited. Incidently, any leaks you do have are easy to deal with because finding replacement parts or replacement tubes is relatively easy with this type of waterbed.
As well as the obvious advantages mentioned for having water bed tubes in your soft sided mattress you also have the benefit of being able to choose whether to go with a free flow or a waveless style of mattress as tubes can be acquired to suit either style. A series of free flow tubes will simply consist of a series of vinyl cylinders of water to suit the cavity size of your bed. A waveless mattress will have tubes that are water filled with fiber inserts or cells in the main chambers. Clearly with all these benefits and comfort choices a softsided bed with tube infill is a great, flexible choice.
Various manufacturers make softsided mattresses with tubes and supply replacement tubes. Some of the more familiar brands that you will easily find waterbed replacement parts for on the internet include : Boyd waterbeds, Somma, Advanced Sleep Products, Monterey, Watercloud, Strata and Land and Sky to name a few.
When ordering replacement tubes or converting from a bladder to tube system apart from deciding which style, free flow or waveless, to go for, you need to be aware of the cavity size of your bed. Apart from general sizes such as king, queen etc you need to know the depth of the cavity between rails and various lengths and widths as these differ between manufacturers and models.
Depending on the size of mattress you have individual tubes can often be purchased on the net for as little as $20 and some full sets can be bought for $50 upwards. Take your time, shop around, there are some great deals going on the internet for waterbed tubes as sets or individual replacement items.