When can I expect results with my filtration system?

The system will start mechanically filtering straight away, but allow at least a month in the growing season for all the plants and the micro-flora to get established. Even when there is very little plant growth in the winter, there should be a certain amount of biological filtration from the bacteria in the gravel. Switch it off in very cold weather; you will just have to hope that everything holds its breath. The algae do tend to find a window of opportunity briefly in the spring since they can grow profusely at much lower temperatures than many of the higher plants, but once summer is in full swing the algae haze is soon dealt with.

Cost?

It is worth experimenting with what you might have lying around. If you already have a multi-chamber biological filtration system, it may be just enough to plant up the last chamber in the series of tanks. Or if you just have a single chamber of the type where the water level rises up through the medium, you could try just planting up the medium.

If you only have a submersible pump supplying water to a waterfall, then the main expense is over. Incorporating a vegetable filter or mini-reed bed at the top can just mean the expense of a header tank, a sheet of HDP or ABS plastic and two cheap plumbers fittings maximum 30. As for the plants they are the cheapest. If you live near rhynes, dykes or waterways that are constantly being dredged on a rotational basis, then common reed, scraped out by the ton, can be rescued by the handful. Gravel is generally less than 2 a bag if you choose the cheapest inert cracker grit.

Tools

The tools you would need if you were starting from scratch with a basic plastic or fibreglass tank:

A glue gun or a silicon glue and dispenser.

A power drill with hole borer attachment for the outlet pipe, which should be a minimum of 40mm. You will also require a hole borer of the size for the inlet hole, which should be adequate for the hose-tail, which in turn should fit the tubing from the pump.

Time wise, even constructing from scratch, the large header tank method of building will take less than an hour to build and probably 2 hours to dig in and fit up.

The number one tip for getting it right

Let them at it!

Above all, get the right plants for the job - the common reed. A decent quantity planted 15cm apart, being fed water from the pool 24 hours a day, 7days a week.

Maintenance?

Just cut the plants back at the end of the year (more if it is Cress or such like). If there is a drain plug accessible on the tank, backwash on an annual basis. Otherwise dig out, divide the plants and replace the gravel every 4 to 7 years.