BonniesPlants.com

since my pond is 150gal im wanting how i could make a inexpensive filter.right now i have my pump in a mini milk crate filled with lavarock.very few plants an a few gold fish.not sure if i want a bio or mechi filter.

There are many types of DIY filters you can do. A number of folks on this forum have made a Skippy filter. Pretty easly to make very popular amongst ponders. You can find construction instructions on the web if you do a search.

Because your pond is only 150g you really can get away with a small filter. The following is a link of a DIY bio-filter made from a planting pot. Pretty neat. check out this link: http://pixelriver.tripod.com/Filter/filter.htm

Another option is you can purchase an inexpensive pressurized filter. An example is the Cyprio Bioforce 500. Supports ponds up to 300 gallons and I've seen them as low as $75. I use something similar to this for my QT.

Bio-filters and mechanical filters perform quite different functions. The purpose of the mechanical filtler is to remove the suspended debris from the water before the pump intake. Also mechanical filtration is responsible of removing the crud on the bottom of the pond. Settlement chambers, skimmers and simple leaf baskets are examples of mechanical filters.

A bio filter use beneficial bacteria to break down fish waste and remove harmful ammonia and nitrite from the water allowing for clear and a healty pond. Many types of bio-filters exist. Some like a bead filter perform both mechanical (removing fines) and bio filtering. Other manufactures also make units that combine both mechanical and bio-filtration (e.g. Savio skimmerfiters). Personally I like to have my bio-filter only perform bio-filtration and not put the extra strain on performing mechanical filtration. But that's a matter of choice.

If you have some ideas what you'd like to try, please post. Plenty of folks on the forum have experience in DIY which could provide feedback on your ideas.
Steve

thanks Steve! i have made a test filter useing a plastic file box.frist i drilled a hole in the bottonside of the box for my intake hose.then i siliconed several peices of pvc fittings to the bottom for a peice of eggcrate to sit on.about 1in from the top i drilled 3 holes for my water to return to the small pool area.i filled the box with rinced lava rock.i had to add 3 return holes because water was running out over top of the box.an not out of the return pipe.i used 3/4in pvc pipe.i looked at several pic an it showed water comeing from the bottom an not from the top(why).looks like it would make more since for the water come in from the top an out the bottom.as i said this is just a test box an kinda playing around.might work an might not.

There are two primary types of filters, upflow and downflow filters.

A downflow filter is a filter with submerged media and the water flows down through the media. Many downflow filters use air bubbles injected below the media to clean the media. Downflow designs have the advantage that you can easily see how much debris has accumulated since it is on the top and it provides better entrapment of sediment at the bottom. A disadvantage of this type of filter is the reliable flow of water. If you gravity feed to a downflow filter and pump back to the pond, the pump can starve for water if the filter becomes clogged. If you pump to a downflow filter and allow water to return to the pond by gravity, you can overflow the filter and pump the pond dry if the filter becomes clogged. You can prevent overflow problems by having plumbing that will allow water to bypass the media if it becomes clogged.

An upflow filter is a filter with submerged media and the water flows up through the media. The primary advantage of this type of filter is that it is is supposed to be more reliable with regard to water flow, but there is the possibility of opening channels though the media, thus reducing its effectiveness of the converter. Also, if not designed properly an upflow filter has a higher tendendeny to carry sediment particles out of the converter and back to the pond. If you setup an upflow filter so that you pump to the filter and allow water to flow out the top and return to the pond by gravity, it is very reliable. A disadvantage of this type of filter is that it is more difficult to check the amount of debris accumulated and more difficult to clean.
Steve

apprently my box is a upflow i have water pumped from the bottom up through the media an out through 2 return pipes.water is pumped from the main pond into the botton of my box an it flow up through the media an out 2 returm pipes into the smaller pond.an it flow back into the main one.if the lava rock becomes a problem i'll switch to ceramic,pot scrubbies or haircurlers or maybe bio balls.the next one will be desighned a bit diffrent.but on the same basic setup.

Always glad to see another DIYer on the forum. When I look back I am not so sure I saved very much going the DIY route especially if the time is added in...but everything on my pond was designed and installed by your's truly. And that's what it's all about for me.
keep in mind the filter "size" is more related to the bio load not the volume of water.
post pics if you get a chance.
John-Paul