How many different "tricks" have you heard regarding how to keep your cut flowers from wilting prematurely? Are a few:

• Put a penny in the bottom of the vase.
  This trick is supposed to work because copper is a natural fungicide.
  The problem with this theory is that even though copper is a natural fungicide, the amount of copper that actually leaches out into the water over a week or two is infinitesimal.
  
• Adding an Aspirin to the water.
  This is supposed to work by increasing the acidity of the water and also acting as a bactericide.
  
• Adding the Flower Packet - most cut flowers come with a packet of chemicals.
  These chemicals contain both a bactericide and nutrients.
  The problem with this is if not mixed in the proper proportions, it can actually increase the bacteria counts.
  
• Change the water every few days.
  This is to replace the water that has become contaminated with bacterial growth.
  

If you notice, the common themes of all of these techniques is that bacterial contamination.
This has been shown to be one of the main causes of cut flowers dying prematurely.
One of the other side effects of bacterial contamination in the vase water is that the water turns rancid after a few days.
Even the directions on the chemical packets that are included with cut flowers suggest that you change the water after a few days.
In today's world of paranoia regarding germs, it is amazing that the common flower vase goes unnoticed.
Published data has shown the a typical flower vase has over 40 different types of organisms at extremely high concentrations.
A new product that filters and aerates the water in flower vases is called the Ultimate Flower Vase.
This product incorporates a self contained filtration system similar to aquarium tanks.
The filtration system which is powered by an air lift tube in the flower vase also aerates the water.
The end result is crystal clear vase water and cut flowers that last significantly longer.