Pond vac 1

Pond Vac

Having put together our shop vac system to muck the bottom of the pond I wanted something to combat the free floating algae in the pond water. Back to Internet surfing again. This time I found a suggestion for an external filter. Our filters are doing a good job but there is so much fine, lacy algae they simply cannot keep up with it all.

I went to Wal-Mart and bought another bag of polyfill batting, a round sprinkler and a tall kitchen garbage receptacle. Again, my purchases were under $20. The only other items needed were a piece of hose and a submersible pump. Fortunately we had both lying around.

The old pump is submersible and moves 600 gallons of water an hour and can completely recirculate the pond water in about 12 hours. We placed the pump is in a sack we made of old, screen door netting to protect it from becoming clogged by algae. We attached an old shovel handle to it so that we can pick up the pump and move it around without having to get into the pond.

External filter inside

Inside of external filter
Poly fill batting
Sprinkler and hose

External filter trash container

External filter
trash container
holes drilled in
bottom, front

External filter hose and pump

External filter
hose from submersible pump
to sprinkler in trash container







A piece of hose runs from the pump into the plastic garbage can filled with polyfill batting. Again we drilled about 9 large holes at the bottom of the garbage can on one side only and drilled a hole at the top on the side to slip the hose into. We attached the sprinkler to the hose end draining into the garbage can. We run this external filter system during the day from about 7am to 11pm. It has been working for about a week and we can see that the water is clearing.


Fish in May 2013

We will never rid ourselves of all the algae nor would we want to. The fish do eat the algae and as they root around the bottom and sides of the pond eating algae they disturb it and the fine stuff floats up to the surface. We do see clumps of this fine stuff on the water’s surface. I have tried skimming with our trusty pool net it but it is so fine, it just dissolves. However, it does float over to the internal filters where it is sucked into the system.

water quality 1

Water quality in May
in Arizona

As we enter the really hot part of the year in Arizona the water is becoming more cloudy and with time, we will not be able to see the fish. The filters will not be able to keep up with Mother Nature’s algae production.  I am determined, no matter the temptation, not to use chemicals this summer for summer will end, the water will clear and we will be surprised at how big the fish became while invisible to us.