Before you Build - Pond Building Concerns

mikey's picture
Submitted by mikey on Sun, 04/05/2015 - 11:35

by Mike Anger

 When thinking about pond construction, there are a number of items to consider even before the subject of filters. Consider its location: how much sun will it receive, are there trees nearby that may provide shade (or be a burden with leaves falling in or roots that could damage the pond)?  Avoid nearby roofs that might have drainage that could enter the pond and be harmful to your fish and plants. Try to avoid a low area of the yard to prevent ground water from entering the pond, and have its perimeter higher than the surrounding area to keep out runoff. Ideally the location should be some place that you can enjoy-closer to, and perhaps where you can see it from the inside of your home.

Size does matter. Despite the recent beautiful weather, we do have cold spells. Depth should be a minimum of 3 feet, but preferably 4-6 feet deep.  The volume depends on many factors-how much space, filter size, number of fish and plants planned and cost. The calculation is length times width times depth (in feet) times 7.54, equals the number of gallons. Ponds may be preformed, concrete (it must first “cure,”), fiberglass, or the newer spray on polyurea.

Ask any Koi keeper and I bet any one would rather be enjoying their Koi than performing pond maintenance; keep it as maintenance free as possible. Use bottom drains to pick up the detritus and ensure that the pond bottom slopes towards your bottom drains (at least 1 to 2 inches per foot) spacing them 8 to 12 feet apart. I am amazed at the businesses that sell supplies and build ponds who insist that bottom drains are not needed! Plan a skimmer to pick up floating debris, and locate it at the opposite end from the waterfall. Waterfalls help aerate the water and keep the water in motion. Jets around the pond also provide aeration, minimize or eliminate dead spots (stagnant water) and exercise your Koi as they swim through or against the current.

If at all possible, consider a prefilter. This will remove much of the solids and debris before water reaches the biofilter, decreasing the need to clean the biofilter and reducing the chance of it clogging up and having reduced efficiency. In my opinion, the best type of prefilter is a below ground vortex. This cone shaped filter has water spinning around and causes settlement of solids. Once water leaves the prefilter, it uses a pump to deliver to the biofilter. Here you need media to allow the proliferation of nitrosomas and nitrobacter bacteria to convert ammonia to nitrites and nitrites to nitrates. There are many excellent types of filters available or you can construct your own. Finally, water is returned to the pond. If you are considering a UV light, here is where it would be placed (after the biofilter).

When building a pond, whether it is your first or a rebuild, spend the time to read, look at many ponds, plan very carefully, examine your budget and don’t rush. The extra investment you put in now will reap many benefits in the future.


!If you're not havin' FUN, you're not doin' it right