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Concrete Filter Construction

Some time ago, Chris Neaves posed the following question to me: “...how many types of pond filters do you think there are?”

I am sure most people would have given the same answer as I did: “I have no idea how many types of filters one can get. I guess as many as people can invent, so the list can be never ending!”


Wrong. The reply I got from Chris made me feel a bit foolish:

“I recon there are only two types of filters and every filter can fit into one of two categories:

1) closed or pressurised filters and

2) open filters.

Each classification has a set of basic rules that applies to it.”

There are so many variations of open filters in use world-wide that it will be an impossible task to try and describe them all. It is also possible to purchase fiters that are actually ready to place next to a pond and connect it up. They come however with a price, and most of the time these filters  must be purchased and then then you can plan the pond's plumbing. This article is about the construction of concrete filters, fed by gravity from the bottom drains. For illustration purposes, I have used one feed from one bottom drain, but it can be constructed with multiple bottom drains, using the same principle. Remember, a filter cannot be too big, so construct a filter that can contain sufficient filter media. A too small or poorly constructed filter will cause you endless maintenance, water replacements and most possibly future disease/loss of some of your fish.

It is not worthwhile to be skimpy when planning and constructing a filter.

Also read this article by Chris Neaves on biofilters as well as the article on flow rates.


Last Updated on Tuesday, 11 May 2010 09:30