To make a nitrate remover you will need the following:
1) Some nitrate removing resin
2) A container to hold the resin.
3) Two plastic hose nozzles
4) An old power head or pump.
You can buy nitrate removing resins from most of the mail order companies that advertise in the fishkeeping press for under £15 a litre. A litre will be enough to remove approximately 50 parts per million from about 500 gallons before recharging with salt water. You will also need some sort of container to hold the resin and some method of passing the water through it such as an old power head or pump. For my filter, I used a 20 inch length of plastic tube about 2½ inches in diameter. The tube needs to be sealed at both ends so two end caps had to be made. The end caps were then drilled to allow a hose nozzle to be fitted at each end. You will need to place something over the inside of the nozzle outlets to prevent the resin from coming out once the filter is assembled, You could use a piece of aquarium sponge or wool. On my filter, I cut two circles out of some scouring pads and placed one in each cap. One end cap is then fixed to the tube and the resin is put in from the other end. When full the other end cap plus scouring pad is fixed on and you have your nitrate filter.
ALWAYS make sure that any stale or salt water is flushed through before using the filtered water.
If you have a high nitrate reading from your tap water, the filter can be connected via a hose to your tap when drawing it off for water changes. The filter will not take mains water pressure though so you must be careful and only run the water through slowly. If necessary you can use the filter on the aquarium directly.(not recommended for soft water or Planted Aquarium as the nitrates are exchanged for salt). This does not however negate the need for regular water changes.
Connect the filter up to a power head and pump the aquarium water through the filter and back into the aquarium. This can be left running as required until the nitrate is removed.
Once the filter no longer seems to be removing nitrate, you will need to recharge the resin. This is achieved by running a salt water solution through it, I always run it in the opposite direction to that when filtering. The solution can be mixed up in a large bucket, then passed through the filter and back into the bucket using the power head in the same way as used on the aquarium.
