Maintenance Services

A Guide to the Pond Start-Up

A thorough clean up in the spring will help your
pond have a long and healthy season.

Old leaves, pine needles, aquatic plant leaves, old flowers, stems, roots, seed pods, you name it, it ends up in the bottom of an inadequately or under-filtered pond. This material will have been decaying all winter long braking down to little pieces, on their way to being “gunk”.

If you don’t get rid of this gunk, water quality and fish health, and general health of this ecosystem, will all suffer to varying degrees, based on how long you let it go.

First, if fish are present, we need adequate alternate housing for them. A half dozen small goldfish have no problem for a couple hours in a 30 gallon trash can half full of fresh, de-chlorinated water. A pond with larger fish, poses a different situation. Adequate sized tanks, 100-200 gallon capacity should be considered in this format, with additional air supplied by an air stone and small air pump.

Cover the tank or tanks with a net or other type of cover to keep the fish from jumping out. Put the tank or tanksin the shade if possible, and periodic checking on the fish is a good idea. You may need to do a partial water change on a tank with large fish after an hour or two, as the stress of moving them, and the small amount of water in these tanks can get ammonia saturated fairly quickly.


The night before the clean out we use Oxy Plus to shock the system. This will ‘granulize’ the sludge and lift it suspended in the water. Also it will lift most of the leaves and dead lily pads that have collected in the floor or the pond. The next morning your pond is going to look like a disgusting black mess with leaves and lily pads floating on the surface. Skimming the surface with a fish net to scoop out the leaves is a real time saver instead of picking them out by hand. It can cut the time in half! Be sure that all of your fish are out of the pond prior to shocking it. Your aquatic plants will be fine. The black water is full of nutrient. Feel free to pump it on your trees and shrubs to get them off to a great start to the season.

Commence rinsing and “boiling” the nooks and crannies, as well as any gravel in the pond, with a high volume 4000+ GPH pump connected with 1 ½ “ or 2” flex pipe on it. This boiling and rinsing should never be done with a garden hose. We use volume of water, not pressure, to clean the pond.

We start at the top of the stream and work our way down. Pump out water to expose the first shelf in your pond. Flush out the organic sludge from the first shelf into the pond. Then expose the second shelf and repeat the process. Once we have the upper areas of the pond “boiled” and rinsed (even with the nasty black water, it works!). We continue to work our way down the pond until we’re at the bottom. You can elect to use a pressure sprayer to clean up the larger rocks or you can pour the Oxy Plus in a pressure sprayer and spray them. We have found this easier and quicker than using a pressure sprayer. The black rocks will return to colour within 10 minutes! Care must be taken with Oxy Plus, particularly in a spray application. Hands and eyes MUST be protected. At this point, we’ll re-fill with enough fresh water to do another “quick rinse” of the entire pond, and then boil and rinse the bottom.

While the pond is empty, or very near empty, is a good time to do thinning of the plants prior to refilling. We don’t strive for 100% removal of all debris, feeling that 85-95% is adequate. We do, however, strive for 100% rinsing and boiling, even with the dirty water.

We normally do these clean-outs “once a year”. Using this methodology, 15X20 pond with fish may take 3-4 hours.

We use 150-200% of the pond’s volume as the basis of our de-chlorinator dosing. Better to be safe than sorry with de-chlorinator. It’s almost impossible to overdose, but easy to under-dose. Once the filters pads, brushes and bio media has been re-installed it is time to connect and turn on the pump and check everything is functioning as it should be.

Re-introducing your fish should be done with care. We need to acclimatize fish to the new pond water. Both water chemistry and temperature. Fish containers can be topped up 50% with the new water by pouring in a few cups of new pond water over two hours. Or better yet, topped up from water via a vinyl tube siphoned from a second container filled with the new pond water. The flow rate should be at a ‘constant drip’. We have found this to be less stressful on the fish.

It is a good idea to keep an eye to an eye-out for the first the first few days after the pond has started for the season. We have found that fish tend to ‘forget’ about the skimmer and are still ‘sluggish’ with the cool water and can get sucked in. They tend to remember if they get sucked in though.

Ensure your pond water level is maintained with an automatic water-fill valve to keep the pond ‘balanced’ and that your pump is always submersed underwater.

Enjoy your pond this season.

Good Ponding!

– Water Works Ponds