These are some of the best and most popular bead filters available for koi ponds and water gardens. There is a reason why they are so popular, they are really good filters and people are very happy with them.  In my experience they are the perfect blend of biological and mechanical filtration.  Many bead filters have special beads that are great for biological filtration (bacteria growth), but not so good at removing debris and waste from the water (mechanical filtration).  That means that your pond water never clears up.  These filters have thousands of small cylinder shaped “beads” that work great for both Biological and mechanical filtration.  It is, In my opinion, the perfect balance. 

     Ultima II filters are available in many different sizes.  The smaller filters can be ordered with 1-1/2″  or 2″ input/output ports.  All other models are 2″ ports.  There is a 30,000 gallon filter that has a 3″ side mounted ports.  That is really a great filter for larger ponds with higher flow rates.  

     The filters are sized as 1000, 2000, 4000, 6000, 10,000, 20,000, and 30,000 gallons.  There is no such thing as “over-filtering” a pond, so don’t be afraid to “size up”.  Having a filter that is slightly larger is only going to keep your pond cleaner.  Just be sure that the flow rates through it are sufficient.  There is a chart below to show flow rates for each size filter. 

     The only suggestion that I can give you, is to backwash these filters regularly.  Do not ignore them.  The cleaner that you can keep the beads, the better your biological filtration will be.  Since they are very good at removing waste from the pond water, it can accumulate in the beads inside the tank.  This keeps the pond clear, but as the sludge builds up, it can suffocate the bacteria growing on the beads, so keep it backwashed, and both the pond and the beads will stay clean, and the filter will work at its optimum level.