How to take care of a lot of fish from a leaky pond.

The biggest problem we had when rebuilding the pond is what to do with our fish. We had five
adult koi from 18” to 24” long and six juveniles of varying size. We were exploring different
options, including stock tanks and show tanks, but that got expensive quick. It would also would
have been challenging to set up filtration on the number of tanks we’d need.

In early 2017, when we were approaching the planned start date, I brought up our problem with
the first pond builder. He suggested buying an above ground swimming pool- one without an
algaecide added during manufacturing. This was a great idea and probably saved our fish. The
brand the builder recommended was Intex because they did not use algaecide in their pool
material. After some internet searching I was able to find a previous year’s model pool for $299
on Amazon. After calling Intex to make sure the pool was algaecide free, I placed an order and
it was on our doorstep 3 days later.

The pool we picked was 15 feet in diameter and 4 feet tall. Based on a water level of around 3
feet 8 inches and pool diameter of 15 feet, the total volume of water for this pool is around 5000
gallons. This is plenty of water for the number of fish we have, and I quickly realized I could use
the Ultima II 20000 filter on the pool if I had a pump. On a club member’s recommendation, I
sized and bought a Performance Pro Artesian 2 5800GPH pump, which I immediately put to use
on the Ultima II filter. We plan to use this pump on the new pond.

In April 2017, I began the pool setup. To even out the ground, I layered sand over the gravel
underneath the pool in our backyard (we plan to regrade and replace the driveway). I
assembled the pool and plumbed in the pump and filter. I ran the 3” pump intake across the
bottom of the pool and put a tee on the end with two drain grates on either side. The intake
plumbing runs up over the edge and down to the pump, through the filter, and back into the
pond. Outflow from the pump is enough oxygenation. We used ammonia salt to kick start the
filter. I added a layer of rigid foam insulation around the pool and filter and built a box for the
pump. Then, with the help of club members, we transferred the fish from the pond to the pool in
May 2017, anticipating the beginning of the construction project.

Nearly a year later the fish are still in the pool. We have had to make some modifications over
the course of the summer and this winter, but the fish have made it through mostly unscathed.
Keeping fish in an above ground pool has been somewhat challenging, mostly due to wide
temperature fluctuations over the seasons and even over the course of a day. That being said, I
am not sure we would have any fish left if we have bought a bunch of smaller tanks and tried to
keep them in tanks for a year. We are really looking forward to having the new pond finished.

Begining to plan the new pond

So you know you have a leaky pond… what now? We were very fortunate that the leak started slowly. The slow leak development has given us time to plan as well as breathing room to make sure we’re making the right decisions. When we realized that we were looking at a major remodel, we starting to think about what we would do differently.

The giant bog filter worked well, but it was now 15 years old and suffered from channeling. We were able to clean it up a bit using MicrobeLift Sludge Remover, but the result was modest at best. Molly wanted a more traditional pond filtration system but I was thinking about rebuilding the bog, though in a more maintainable configuration. The year before, a former IWGKS member gave Molly and Sue Boydstun an opportunity to salvage some old equipment. This included an old Ultima II 20000 filter. Boy was I surprised to see that in the back of the truck when I got home from work that evening. The filter was the factor that pushed me over to my wife’s way of thinking, and the bog was out.

I refurbished the filter in spring 2017 by adding a new valve assembly (ordered from Aqua Ultraviolet), repairing the jets (by mending the molding seams), and cleaning out the old media. The filter became the cornerstone of our filtration system. Ultima IIs have some known drawbacks, like easily clogged media, but for us a $500 refurbish job beats a new $3000-$4000 filter. There are documented ways to improve the operation of the Ultima II: using compressed air for cleaning and ensuring adequate water flow through the filter.

With the filter in good shape, I dove into the filtration system design. I did a lot of reading about PVC pipe diameter, friction loss, head loss, water speed, solids settling, etc. I’m still learning new stuff every time I get into research mode. I was a planning on getting a fine art degree in college and I have felt (only a few times) that I should have gone into mechanical engineering. At some point, I felt comfortable enough to try to get my ideas out on paper and drew up a first draft concept of how the system would work.

Any experienced pond engineer will tell you this design isn’t great, but you have to start somewhere. I believe this is an important step for any project because it allows you to coalesce the swirling bits and pieces of information and theory into something you can visualize and refine.

With a plan on paper, I started to figure out how to position the new pond and its equipment within the current footprint of our pond. The obvious place to put the equipment was in the bog garden. Because the pond will be one giant hole, we need a structure to separate the equipment, such as a concrete or block wall. The liner will extend over the part of the wall forming one end of the pond to keep the equipment area dry.

This was the first iteration with everything roughly laid out. There are some obvious design flaws (each bottom drain needs its own pipe), but it’s only draft #1.

As the project has progressed I have able been tap into some extensive knowledge from local IWGKS members. While the details of the design have changed, the overall plan is still fairly similar to these original drawings.

The neighbor’s cat is wondering what is going on….

The 2018 Pond Remodel is Happening!

We bought our house in 2010 knowing it was going to need work. The pond, however, was one big the selling points. The pond was installed by the previous homeowner who claimed to have worked as a landscaper. For six years, unlike the other work the previous owner did on the house, the pond ran well and we only had a few minor issues with it.

As you can see, the pond was a two-level layout. The upper level was a bog garden, the only source of filtration. The lower level was five feet deep under the waterfall and gradually declined to six feet deep below the skimmer. There are no bottom drains and the bottom of the pond is covered with three quarters to one inch-sized gravel. We estimate the volume was about 11,000 to 13,000 gallons.

Two years ago (early 2016) we noticed the pond needed topping off far more often than previous years. In late 2016, we were losing one to two inches of water a day and we began planning a remodel for early 2017. Unfortunately, the contractor we started to work with moved on to another project around the time we were planning on starting and we scrambled to find a landscaper. In the meantime the leak in the pond had progressed to losing four inches of water a day and we moved the fish into an above-ground swimming pool. The fish seem to be fine in the pool, waiting for their new pond.

Fast forward to 2018 and we have found a reputable landscaper named Urban Escapes and are working on the final touches to the planned remodel. We’re now about a month away from the start of the pond remodel and will try to share as much of the process as we can, and some of what we have learned as well.