Need to find a new water tank

you may need to empty the water that went into the base and retry putting the top tank back on sometimes too much water gets into the bottom and it wont put out vapor. at least mine does that and it is an ionic cool mist humidifier which means uses no filter

You may be over filling the unit. Take the refillable water tank out and with the power removed try to remove all the extra water where the tank goes. check for anything that looks cracked inside the unit the best you can. If the tank is seating properly it should not leak. If it is filled properly it should not leak.

I am wondering if the floater is sticking. I have the same problem and there is no crack like others have mentioned. But when taking it apart I noticed the floater which is the piece that sticks up from inside the base was not easily moving. Taking it out tonight after work and cleaning it along with the filter.

ask at http://manualfox.com/link/sunbeam.htm
They will find it for you.

FILLING THE WATER TANKS
1. Before filling the water tanks, push the POWER switch to the “OFF” position and
unplug unit. Refer to cleaning instructions.
2. Remove water tanks from base, turn each tank upside down and remove tank cap
by turning counterclockwise. Fill tank with clean cold tap water.
Replace the tank cap by turning clockwise. Tighten firmly.
3. Carefully pick up tank, since it will be heavy when full, and slippery if wet.
4. Place water tanks on base. Make sure tanks are properly placed, otherwise, the
humidifier will not work correctly.

Have you cleaned the unit lately? The following is from the owners manual.
1. Turn the humidifier ‘OFF’ and unplug the unit.
2. Lift the main housing and remove the water dispersion tray and the PermaWick™ Filters. The motor is attached to the main housing. Do not place the motor near water. Do not use a wet towel on the motor or motor housing as electrical shock may occur.
3. The PermaWick™ Filter should be cleaned in a vinegar and water solution to remove any mineral buildup. Place in a solution of one (1) gallon of water and eight (8) ounces of undiluted white vinegar. Allow the filter to soak for 20 minutes.
4. After soaking, rinse it several times with clean water. Place the PermaWick™ Filter in a location where it can drip dry while you clean the other parts of your humidifier.
5. Remove the water tank from the base and empty any water that is left in the tank. Soak the base in a mixture of one (1) gallon of water and eight (8) ounces of vinegar for 20 minutes.
6. After soaking, wipe the base with a soft cloth or sponge to remove any mineral build up. Rinse with clean water several times. If you are planning on storing the humidifier, be sure the base is completely dry.
7. Fill the water tank with one (1) gallon of water and eight ounces of undiluted white vinegar. Replace the tank cap and shake the tank vigorously until all interior surfaces of the tank have been exposed to the water/vinegar mixture.
8. Empty the tank of the water/vinegar mixture. Rinse it several times with clean water and then replace the tank cap. If you are planning on storing the humidifier, dry it inside and out, leaving the cap off to allow the tank to completely dry. Continue to clean the other parts of your humidifier.
9. Remove the water diffuser cap by squeezing the two tabs as shown in Figure 3. Rinse the cap in clean water to remove any debris. If the cap contains hard water residue, soak it in a mixture of one (1) quart of water and two (2) ounces of vinegar for 20 minutes. 41553-01 01/03/2008 6 © 2008 Hunter Fan Company
Rinse well and reinstall the water diffuser cap. Do not expose motor or other electrical components to water.
10. Wipe the surfaces of the main housing with a soft cloth.
11. Once all the parts are clean, reassemble the humidifier, and follow the USING YOURHUMIDIFIERto continue use. If you are storing the humidifier, make sure the parts are completely dry, reassemble, and store in a dry location

Try to just fill the tank with water and set it upright on a table. If it leaks, the tank is cracked and needs to be replaced. Order one at kaz.com (search using model#). I have had this tank leak if the special cap is not sitting properly on the base. Make sure that the steam tower is properly locked in place before you place the water tank in the reservoir. The cap on the tank has a spring release that has to be correctly lined up so it only releases water when the water level in the reservoir drops.

Caring For Your Venta-Sonic Humidifier
IMPORTANT!
Always unplug the unit before cleaning!
When to Clean Your Humidifier

Clean your humidifier weekly or more often during heavy use, depending on your
individual water quality. Clean your humidifier before storing and after long periods
of storage.

When cleaning the inside of your unit, keep water away from the air outlet. Exterior
may be wiped with a damp cloth when unit is off and unplugged.
Cleaning the Oscillator and Water Sensor

Turn off the unit and unplug power cord. Remove tank from base and empty
reservoir in base. Use cleaning brush provided in base to clean off mineral deposits
and sediment from oscillator and water sensor. Do not scrape or clean with tools
that have metal parts. Be careful to not damage the surface of the oscillator.
ATTENTION: Damage to the oscillator may cause the unit to not work properly.

The oscillator (ultrasonic transducer) is highly sensitive. Keep this important part
clean and treat gently. Do not touch the oscillator while the unit is operating.

Do not use soap, cleaning agents, detergents, or other chemicals for cleaning the
tank and humidifier.

After cleaning fill water tank (see instructions above) and return tank to base.
Storing the Venta-Sonic
Switch off and unplug power cord from A/C outlet. Empty remaining water from base
and tank. Clean tank and unit (see for instructions above). Make sure all parts are
thoroughly dry—allow at least 24 hours to dry. Leave the filling cap of the tank
loosened. This will keep the cap and gasket from sticking together. Pack Venta-Sonic
in original packaging and store in a cool and dry place.

You can find your manual at this link:
http://www.venta-sonic.com/pdf/vs207manual.pdf

Good Luck.

Your V5100N ultrasonic humidifier generates a fine mist by vibrating the water at an exremely high speed. The water doesn't actually evaporate until after the water mist is in the air. As the tiny water droplets evaporate in the air, the calcium and other minerals settle on your floors and furniture.

Humidifiers that evaporate the water in a filter wick, or with heat, do not generate dust because the water evaporates inside the unit and the calcium is trapped inside.

You can avoid the dust problem with your humidifier by using distilled water. Distilled water is available in most stores that sell bottled water in gallons...but be sure to choose "distilled" water, not "purified" water. Try the distilled water in your steam iron also...if you have one. It will last longer.

http://homeappliance.manualsonline.com/manuals/mfg/vicks/v3100.html

This is the link to your manual.
Daily Maintenance
1. Turn switch to OFF position and unplug the cord from wall outlet.
2. Lift the Water Tank from Base. Carefully remove the Water Tray from the base being
careful not to damage the delicate Wicking Filter. Empty excess water from the Water Tray
without removing the Wicking Filter. Remove the Tank Cap and drain any water from the
Water Tank. Rinse the Water Tank with lukewarm water after each use. Wipe accessible
surfaces of the Water Tank and Water Tray clean with a soft, damp cloth.
3. Do not immerse the Base in water. For storage, wipe dry with a soft, clean cloth. Keep
water away from the Air Outlet.
4. Do not leave water in the Water Tank or Water Tray when unit is not in use as it may
result in the build up of mineral deposits and bacteria that can inhibit the output
efficiency of the humidifier. Please note that if water remains in the Water Tank for more
than a day or two, bacterial growth is possible.
5. Replace Water Tray with Wicking Filter. Then replace the Tank. Humidifier is now ready for
use.
Weekly Maintenance
Removing Scale
1. Remove the Water Tank and empty any remaining water from the Water Tank.
2. Turn switch to the ON position, either low or high speed, and operate Humidifier until the
Wicking Filter is thoroughly dry.
3. Turn switch to the OFF position and unplug the cord from wall outlet.
4. Remove Wicking Filter from the Water Tray by carefully lifting straight up taking care not to
tear filter.
5. Remove the Water Tray from the Base. Fill Water Tray with undiluted white vinegar. Let
stand for 20 minutes.
6. Dampen soft, clean cloth or sponge with undiluted white vinegar and wipe out Water Tray
to remove scale. Do not use soap, detergents or abrasive cleaners.
7. Rinse the Water Tray thoroughly in clean warm water or put in top shelf of dishwasher to
remove scale and vinegar before disinfecting the Water Tray.

Disinfecting the Water Tray and Tank
1. Fill tank with 1 teaspoon of household bleach in 1 gallon of water. Let stand twenty (20)
minutes, shaking vigorously every few minutes, drain and rinse with clean water until the
bleach smell is gone. Dry with a clean cloth or paper towel.
2. Wipe the Water Tray with a soft cloth dampened in the bleach and water solution. Rinse
the Water Tray thoroughly or place in dishwasher before proceeding.
3. Wipe all exterior surfaces of the Base with a soft, dry cloth. Do not immerse the Base in
water or use water to clean the base. An electric shock may result or the humidifier may
be damaged.

Hope this helps.
Good Luck.