Many water heater in the mid 90s had faulty dip tubes. This occurred with many brands because the producer of the dip tubes sold the tubes to many companies. As you may already know, cold water comes in at the top of the tank, goes into the dip tube which carries the water to the bottom of the tank. If the dip tube breaks off, the cold water does not go to the bottom of the tank so the lower part of the tank has only cold or at best warm water. Checking and replacing the dip tube is quite simple. Turn off the water, the disconnect the intake line from the tank. Remove the nipple that is threaded into the top of the tank. The dip tube simple hangs by it's flanged end in the opening directly under the nipple. You can use use your finder to fish the tube out. It should be long enough to go clear to the bottom of the tank. If it has broken, you can get a new tube at any plumber shop or hardware. It it is too long, just cut the end off. Replace the nipple and reconnect the water line and turn the water back on. It is not necessary to drain the tank to do this, but if you do, be sure you do not turn the gas back on until the tank is purged of air.