Filtration Putting it simply

Most beginners believe pond filters work by removing physical dirt and this keeps the water sparkling clean.

Unfortunately this is not the case, although a small amount of waste will be strained from the pond as it passes through the filter.

The most important part of the filters job is to act as a mini sewage system for the pond. In simple terms the media within the filter creates a huge surface area, which becomes home to many millions of helpful bacteria.

When physical waste such as fish waste, excess food or decaying organic material fall to the bottom of the pond it starts breaking down and releasing toxins into the water. As the water passes through the filter the helpful bacteria break down these invisible toxins and any other organic waste which get caught up in the filter.

More advanced filter and pump systems will strain out more solids from the water, but it must still be remembered the filter has to biologically break this organic waste down, and the most dangerous toxins are invisible to the eye. Clear water does not mean healthy water!

Hence it is vital to purchase a filter, which can easily cope with your pond volume and anticipated fish stocking level! Please always check the capacity of your chosen filter with a member of staff.

BIOLOGICAL – HOW DOES IT WORK?

Although there are many different designs, the principle behind all biological filters is the same. They contain filter material through which the pond water must be pumped 24 hours a day.

When first starting up a filter it will take a period of five to six weeks for helpful bacteria to build up in the filter material. These bacteria will break down Ammonia, which is caused by dead and decaying organic matter, into Nitrite. A different type of bacteria then breaks this dangerous Nitrite down to Nitrate, which is harmless except in high concentrations, and will be absorbed by plants as they grow.

DO ALL PONDS NEED FILTERS?

No. If you are intending not to have any fish, or you’re creating a wildlife pond with high plant stocks and just a few fish you probably will choose not to have a filter, and try to create a natural balance instead.

NATURAL BALANCE...

Creating a natural balance is simply creating a complete eco- system or balanced nitrogen cycle within your pond. This will take much longer to establish than using a filter.

However, the principle is very simple. You will need plenty of plants, probably covering two thirds of the pond area. These plants, along with helpful bacteria occurring naturally in the pond, will then use and digest any toxins left by fish and rotting organic waste, hopefully providing a good natural balance and a clear pond. It is important to remember that the plants should be well established before gradually introducing fish and it could take at least eighteen months to create a balance.

DIFFERENT TYPES OF BIO-FILTERS

There are three basic ways filters can be fed from the pond, and this will affect the positioning of the filter.

Gravity Return Filters. These filters are pump fed with gravity outlet. These will require a pump in the pond that feeds the filter. Water will then simply pass through the filter and return to the pond under gravity. This means the filter outlet must be higher than the point at which you want the water to return.
Pressure Filters Pressure Filters are ideal for small to medium size pools and are directly fed from a pump in the pond. However since the filter is a sealed unit the water is still under pressure when leaving the filter, allowing much more flexibility in the positioning of the unit.
Gravity Fed Filters Gravity Fed Filters are ideal for larger Koi ponds. They are complex units to install and expert advice is available in our stores.

Filter Maintenance

When cleaning out filter material, always wash it in pond water rather than tap water, as tap water contains chlorine that will kill the beneficial bacteria. Bacterial supplements are now readily available and can be used to boost the performance of the filter during the course of the season. They are also particularly useful to use when you have just installed a new filter, or cleaned an established one.

Remember: The more mature a filter becomes, the more efficiently it will work. Therefore only clean the filter materials when they start to restrict the flow of water through them and never clean all the material at the same time.

WHICH ONE?

At World of Water you will find a huge range of filters. All the filters in this manual have been given three different ratings for varying pond conditions, as illustrated by the symbols below.

Follow these simple steps to find the filter that suits your needs.

If you don’t know your pond volume, refer to pond volume page
Pick the symbol from below that most represents your pond stocking level.
Study the different makes and types of filters and pick the type best suited to your needs.
Look down the column with the symbol, which represents your pond until you find one which easily handles your pond volume.
Always go up one model if it only just copes with your pond volume or your pond is in direct sunlight. Also remember fish grow and breed!

Remember: the more fish in a pond, the more waste generated, and the more helpful bacteria needed to break it down - therefore the bigger the filter the better.

POND ENVIRONMENT	FILTER SYMBOL to select
Heavy planting/few fish
Medium planting/Average fish stock
Light planting/Heavy fish stocks

To go directly to the relevant part of our on-line store:
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It is simply impossible to have a filter too big for a pond,
and koi ponds with such large fish should have the biggest filters of all.

Tips on Installing A Filter
	MOST filters have a gravity outlet therefore the outlet must be higher than the point of return. With gravity outlet filters, keep the return pipe full bore, gently angled down and as short as possible. To maximise water flow ensure the largest possible inlet hose is used, usually 2.5cm hose or above. Most top outlet filters will work better if partially buried keeping the sides tight around the media when full of water. Always follow manufacturers instructions for individual model requirements.
Tips On Running A Filter..
	Filters must run 24 hours a day (Certainly from March to October). Pass your pond water through the filter at least every 1-2 hours. Regularly check pump pre-filter to ensure good flow. Remember a filter will take weeks to become biologically active. Clear water does not mean healthy water. Test your water regularly. Use a bacterial supplement to start and improve filter performance. Always clean filter material in a bucket of pond water not in tap water. Only clean media when flow is being inhibited. Always test water and seek advice if fish suddenly look lethargic or unwell.