What kind of filter are you using? Is it just the underwater pump filter? Those underwater filters don't really do a lot. They are mainly to prevent anything from entering the pump. What most ponds with fish need is an out-of-pond bio filter. The main reason the filter is there is to grow a good aerobic bacteria culture to eat up the ammonia from the fish waste. It's called aerobic because it uses oxygen and needs oxygen in the water as it flows through the medium.

Just get any kind of tub or plastic, terracotta, etc. pot or container of almost any kind (not metal or wood). Fill it with something that has a lot of surface area for bacteria to grow on (not metal or wood) like nylon dish scrubbies or nylon bath scrubbies, pure lava rock is great for this (bags in the BBQ section) or store bought bio filter medium (not at all necessary). Put the pot somewhere near the pond and flow the water from the pump into the top of the container, then through the medium, then out the bottom and back into the pond. The outflow needs to be four times the size of the inflow or the water will just flow over the top.

A really good way to do this that looks good is to use a very large decorative pot and put it in the pond, sitting on something inside the pond. Drill a hole, in the bottom of the sides, that is at least four times the size of the hose going into it or several smaller holes equal to four times the inflow. Run the hose from the filter into the top of the pot and let it run through the medium and out the bottom. Grow water plants in the pot, like impatiens.

I used a large terra cotta pot for this but they are very heavy. Resin would work better and be easier to drill holes in. I drilled a small hole in the very bottom and ran the hose up through it to the middle of the top. It stuck out of the lava rock about an inch, straight up. So the water shot up into a small fountain and back down into the pot, through the lava rock and out the bottom holes into the pond. I had about six hose-size holes drilled around the bottom. This is call a "trickle tower filter". You can put any kind of filter medium into it and just put a few rocks on the top for looks. Smaller medium like quilt batting can be used but it has to be cleaned a lot more often. I only cleaned the lava rock once or twice a season. You can get creative here, using materials already on hand or bought at the dollar store/Walmart. Like I said, it's not to catch "stuff" but to grow bacteria that you run the water through. It's the only way to keep the ammonia down.

If you want to seriously clear a large murky pond, you can use a barrel with an outhose in the bottom that is at least four times the size of the inflow hose. Run the inflow hose from the pump. The water runs into the barrel, through the medium, and out the larger outflow hose at the bottom, back into the pond. Fill the barrel with smaller, finer medium like quilt batting or sand. Dump it out and rinse it off about once a week. Don't use chlorinated water for this or you will kill all the good bacteria growing in it that eats the ammonia. The barrel doesn't need to be sealed. You can keep it out of sight around a corner or behind a fence, etc, if you have a big enough pump to get the water there. Gravity will flow it back into the pond if you set the barrel on cement blocks. This can be temporary, but you will need a permanent out-of-pond bio filter that runs daily, it just doesn't need to be that big.

Don't use chlorinated water to rinse any of your filters or you will kill off the bacteria that eats the ammonia. Also, the chlorine will be washed into the pond when the filter is back in action. Use pond water for this.

It takes aobut two weeks to get a fair bacteria culture growing in a new filter. You can speed this up by seeding it with medium from an already existing filter, i.e. from your pond pump or an aquarium or ask a friend with a pond for a few small pieces of his/her filter medium for seeding.

Well, that's my tretise on pond filters. Sorry it is so long. The out-of-pond filters really do work better than the pump filters for keeping the pond clear and healthy.

The filters we use offer easy care. You simply take off the lid and pull out the mat(which collects the debris), rinse the mat off with a hose and then put it back in the filter. If you would like to find out more please visit

www.californiawaterscapes.com or call (818) 247-9595

Here is a link that might be useful: Pond installation and supplies