Week two of pond - The water is slime green. I mean, really slimy. The big bad green algae has set in, and from the looks of it, it's not leaving anytime soon. Sure, the water has to reach some type of yin/yang balance where the good is in balance with the evil. From the looks of it, the pond may need a little extra help to empower the good forces.
With my old pond, which was no more than 600 gallons, I used a 5 gallon bucket, placed a pump in the bottom with an outlet pipe raising up 2-4" below the water surface. I then filled the bucket with lava rock, places some filter pad over the top and sunk it to the bottom of the pond. It worked like a charm. The water was never crystal clear, but it maintained a pretty good balance. My new 3000 gallon pond is going to need a bit more than the bucket treatment.
Extreme conditions in the large pond calls for an extreme bucket! Pictured here is a 50ish gallon farm supply watering trough. A watering trough works better than most rubbermaid totes, because the plastic is thicker and it is less prone to bulging. Pictured here, the trough has two pipe bulkheads drilled through the side. The first is a 1" PVC line. This is the water inlet and will run from the pump in the pond to the filter trough. Unlike the filter bucket mentioned earlier, this system remains outside the pond. In fact, this filter is sitting on the side of the house right next to the air conditioner. Eventually, I'll build a fence wall around all this utility stuff. The second bulkhead is a 2" water outlet. Water will run out of this hole into a 2" flexible pipe which will transport it back to the pond.
In this image, you're looking into the top of the trough. I have placed a grid on a number of bricks, which provides a platform on the inside of the filter unit. Eventually, the pipe you see jetting out in the picture (water inlet) will go down through the grid, where the water will be injected into the bottom of the trough. Filter medium will be placed on top of the grid. Why the space at the bottom of the trough below the grid you ask? This is an area that will allow filter scum/sludge to accumulate.
This is a biological filter unit. Colonies of good bacteria form on the filter medium, water passes through it, and the bacteria eat the evil out of the water (including algae).
I plan on going one step further with my filter. I'm going to put a UV filter inline on the water inlet, which will nuke the chlorophyll that then gets stuck in the filter that the bacteria then eats. Guess what - the bacteria also produces a bi-product waste. This waste (fertilizer) plants love and can eat thus producing oxgyen for your pond. Whew... that's one heck of a cycle of life!
I'll keep you posted on the success of my homemade filter.