Cleaning your pond

The debate I've seen goes pretty much 50-50 when it comes to cleaning a pond.Some folks do and some don't believing to let mother nature take its course.But nature has a way to correct things that we'll never be able to recreate in our ponds and in certain cases wouldn't want to.And those with larger ponds its possible that its just not feasible to do a complete pond cleaning.Either by sheer water volume or in the instance where some cover the bottom with sand or gravel.Our pond is approx 1000 gallons and we used a liner in installation.The decision to clean the pond came about after talking to a neighbor who's retired from water and waste management.

The story relates to how algae and debris when left unchecked can cause an occurance called "Rollover".What happens is that after repeated algae blooms and normal falling debris from your plants and trees ect fall and settle to the bottom of the pond it depletes the oxygen at the bottom of the pond.As the area on the bottom becomes dead the material starts to decompose and gases start to form.These gases start to rise or rollover and come to the surface.When this happens it can zap the rest of the oxygen in the pond. In no way am I'm saying this will happen to you if you don't clean your pond.But this is natures way of correcting a problem.Most folks have some type of pond maintenance schedule . Keeping as much debris as possible out of the pond along with healthy plants and some type of water exchange such as a pump that circulates water from the bottom can keep this from happening.

So here's how we did it.

The night before the big day we purchased a plastic kiddie pool for the fish.We set this as close to the pond so transferring the fish would be as quick as possible.We then started draining using the filter/pump in the pond along an external pump we had on hand.While the water level was dropping we removed all the shelfplants and set them in the shade.While we had them out we did some repotting,rinsed debris from the gravel off the top of the containers and added new gravel where needed.

When the water level dropped enough we were able to net the fish out.Even in a small area this wasn't easy.We got the fish to the pool.At this point you'll need someone to watch the kiddie pool or cover it with some sort of netting.The fish can and will jump out.The image below shows what I did to correct a problem with the pump clogging. I just took a small bucket,drilled some small holes near the bottom so the larger debris wouldn't enter and clog the pump.

Now the fun part. We had gotten as much water as possible out of the pond. What was left we scooped by hand. And if you wonder yes we did this slowly and checked for critters. We came up with 2 bullfrogs and two salamanders.These were kept in a bucket by themselves. All told we removed about four 5gallon buckets of debris from the bottom. A lot of the junk in the bottom was old roots from the hyacinths we had last year.The nibbling from the koi took its toll it would seem.One problem we had when we first built the pond was using mesh baskets. We had been told that wrapping the inside of the basket with cheesecloth would keep the soil in.Didn't work!We now only use solid containers and hopefully large enough so the koi won't turn them over.

Refilling the pond took about 45 minutes. We have a well and county water so it filled rather quickly.We also had checked the water temperature before we started and there was only a few degrees difference between the old and new water.The white PVC pipe you see in some of the pics is a filter I'm working on.As soon as I'm happy with its results it will be rearranged and hidden. Note that if you use well water to fill your pond it may have low levels of oxygen in it.Some type of aeration may be needed to help put oxygen back into the water.Also a lot of well water contains metals/minerals that may be harmful to your fish.A suitable treatment can be used to correct this.

The fish are back as are the frogs and salamanders. We returned all the plants and after several weeks we haven't lost a fish and still have the frogs.Haven't seen the salamanders but then again we never knew we had them to begin with.We've had alage develope back on the sides of the pond and had a small algae bloom but the waters still pretty clear.

All told this cleaning took approx. 4-5 hours from start to finish. There wasn't much of a work stoppage during this project except for catching the lone koi that decided to jump out of the kiddie pool.I've now been on both sides of the fence with this debate.I've done a total cleaning and also done just a partial one.The last part meaning that I drained about 2/3 of the water out,removed plants, ect.Which is best?Timewise both take approx the same.I've come to the conclusion(for me anyways)that the partial cleaning is a little harder but is a less radical change to the pond and its inhabitants. If you decide to clean your pond by draining it completely be sure and cover whatever you use to hold your fish.

Again let me stress that the rollover mentioned above may never happen to you. But it happens in nature when a lake or ponds oxygen supply is depleted. My neighbor has seen this happen with bodies of water covering an acre or more. His advice is that if this is a concern with you then check with a local agricultural agent or local university.

One thing I'd like to stress is that a pond cleaning should not be a one person operation if at all possible.Meaning that a ponds sides and bottom can be extremely slick.All possible care should be used when entering and exiting to avoid a bad fall.