Claire Corlett

Fish Food, Fish Tanks, and More


Hi I’m Carl the landscape guy and today I’m
building an indoor koi tank. It will be a fully functioning tank and filtration
system where small koi or other fish can be temporarily quarantined. The system will consist of the following materials. For a basin, I’m reusing this 700 liter
food-grade pallet box. This 90 liter large concrete mixing tub will
serve as a pre-filter and sedimentation tank to filter out the coarse dirt. There are also various small parts that will
be used, like this wall bushing and a suitable sealant compound. With this and the pipes, the whole system
will be connected to each other. Then we have this ball valve as well as High
Temperature pipes and PVC pipes. These brushes will later be installed in the
mixing tub. I didn’t want to build a filter with any
sponges because they clog up immediately and have to be cleaned often. Therefore, I bought these brushes that are
15cm and 10cm in diameter, and we’ll see how we make them fit into the tub later. And then we have this rain barrel, which I
want to utilize as a biofilter with Hel-x Biomedia. This basic pump that runs 2000 liters per
hour will provide the necessary circulation. These are the main components at a glance
and I’m looking forward to the assembly and the end result. The unique thing is that the filter system
will work as a gravity system. The water surface in all three connected tanks
is at the same height and the pump simply creates the circulation from one spot. This saves energy in contrast to pumped filter
systems and the functionality has been proven. But one thing after the other, then the structure
will be clear. First we’ll begin with the construction
of the brush filter from the rectangular 90 liter mixing tub. The water should run straight through the
tub and the floating particles should settle at the bottom and on the brushes. To achieve that affect, these 75 mm wall bushings
are installed at the front and rear of the tub. These are installed with the included stainless
steel screws. I put the flange piece on the outside and
mark the opening. With a 10 mm hole, I can then easily use the
jigsaw to cut it out. Use a file to clean up the cut edge. Then I insert a 75 mm pipe through the opening,
and it fits. Now the flange piece can be placed in the
center and I can drill the holes to fit exactly. Next, I roughen the surfaces with sandpaper,
so that the sealant has good contact with the components. All the surfaces should be smoot . I wipe
off the dust and then use Aquaforte’s Superstrong Fix & Seal. This can be easily applied with a silicone
press. I apply an outer and inner ring on the surfaces
of the wall bushing. I start with the flange from the inside and
align it with two screws. I press some of the sealing compound into
the screw holes so that they are waterproof afterwards, but I’m not really sure if that’s
necessary. I turn the two screws so far in that they
protrude out the other end. Then the outer flange can be aligned quite
well and I can start putting the rest of the screws. This will squeeze out some of the sealant
on both sides, but that’s a good thing, because you know that enough sealant was applied. Then I wipe off the excess material. This sealant is not to be confused with glue,
because Polyethylene or Polypropylene can not be glued. The sealant has a strong adhesive property
and is pressed against the side by the screws, creating a permanently sealed connection. I installed the opposite wall bushing the
same way. I’m now putting another bushing in the bottom
of the bucket. This 40 mm bushing is intended to serve as
a drain when cleaning the filter. I have installed all bushings with the flange
to the outside, so that there is as much space as possible for the filter brushes. In addition, the filter should be able to
be emptied out as much as possible when it’s being cleaned. So we will let the sealant dry thoroughly
and take care of the brushes. These are going to be hung in the filter. I simply use a piece of a cable channel, because
it is light and yet stable due to its angular shape. I cut three pieces to length and put holes
in them at the appropriate intervals. Now the brush ends are bent over and inserted
into the holes. Each row has two 10 cm and two 15 cm diameter
brushes and that is pretty much the width of the bucket. The nice thing is that you can now simply
push on the cover of the cable duct and you’re done. There should be no large gaps between or alongside
the brushes, so that the water can slide through evenly and no channels are formed. I ordered the brushes 30 cm in length and
shortened them a bit. Nice and light and stable at the same time. I made three of them and that’s what it looks
like. I take the brushes and lay them in the pond
until the indoor tank system is put into operation. This way, beneficial bacteria can settle on
the brushes and the filter will retract faster later. Next, it’s time to glue. The first thing I will do is glue the filter
drain. These PVC pipes can be glued to the PVC feedthroughs
with the help of some PVC glue. I’ll link all used materials and products
in the video description. It is important that no HT pipes are glued
in here, because they are not made of PVC. I cut the pieces to fit and roughen the gluing
surfaces. The pipes can be easily cut to length with
a metal saw, because it has a very fine saw blade. Then I coat both surfaces with glue and assemble the components. On the 75 mm flanges I put short PVC pipe
pieces, so that I can later push on a 75 mm connecting pipe sleeve easily. Initially, I had planned to glue all the piping
together, but then the system would be too inflexible for modifications. Now the brush filter chamber is glued and
can dry by itself. Let’s continue with the 200 liter rain barrel,
which I want to use as a biofilter. Here the pre-filtered water should run into
the upper area, then flow from top to bottom through the bio-filter material. From the bottom the water is pumped into the
tank. So a 75 mm wall bushing comes into play here
also. The process is the same as before, so we’ll
do it a little faster this time. Also here a piece of 75 mm PVC pipe is glued
in such a way that later an HT sleeve pipe will fit well onto it. In order for the HT-sleeve to later seal well
with the built-in sealing ring, only the adhesive surface should be roughened and the sealing
surface should remain smooth. Down in the rain barrel, I’m installing
a 40 mm wall bushing for the pump line. A PVC connection piece is then glued in here,
not only on the outside, but also on the inside. So that the pump can be easily connected from
the inside. Now we come to the installation of the actual
tank. I bought this very sturdy pallet box second
hand. It already has four holes in it with one on
each side. Two of the holes I close with a corresponding
rubber stopper and the other two openings will later serve as side drains. To do that, I extend the hole to the specified
connection size, 63 mm. I use the Bosch cordless jigsaw again and
saw out the connection carefully. This works relatively well, but you have to
touch it up with a file of course. Clean the edges, smooth with sandpaper and
then remove the dust. I found these rubber seal gaskets on Amazon
that fit this 63 mm opening exactly. To make sure that they stay sealed well I
apply some of the flexible sealant. Directly after that, an HT pipe 50 mm can
be put in, which then also ensures that the sealing compound is pressed on tightly. A little salad oil helps when inserting and
is more fish-friendly than pipe lubricant. The HT pipe elbows can now be reattached to
the two connections. I connect both side drains together and go
over to a 75 mm connector, because this is where our brush filter will be connected later. Now I need one last wall bushing for the return
line from the biofilter. To do this, I put a 40 mm bushing into the
pallet box further up. The box is stable and thick-walled, so the
bushing is easy to install. The flange faces out so that the fish won’t
bump into it later. For a watertight connection, a short piece
of PVC pipe is glued in on the outside. Since it is a used pallet box, it’s pretty
scratched up. To prevent the fish from getting injured on
the bumps, I sand the box from the inside. Now all containers are cleaned and rinsed
out. And finally the construction of the system
begins. First, I set up the two filter basins. Of course, the brush filter must be raised
up so that the water level can be the same in all the containers. I put bricks underneath, but anything should
work, as long as it’s stable. On the bottom of the brush filter container,
the drain valve is screwed on. We had everything glued, so now the rest is
done quick. Align the bricks so that the valve is reachable
in between them. So that the distance to the wall fits I put
the elbow pipes on the back. When that fits, I put the basin in front of
it and connect the 75 mm pipe to the brush filter container. On the other side I connect the pump outlet
at the bottom of the biofilter with the return to the tank. I purposely don’t use 90° elbows, which
will lessen the pipe resistance in this pumped line. Down in the biofilter, I now install the pump. With the help of a 40 mm rubber seal gasket,
it can be very easily connected to a 40 mm pipe and then you can simply connect it to
the pump. This way I don’t need to use thin hoses with
high pressure that can easily bend. The only thing missing from the piping is
the connection between the brush filter and the biofilter. Here I cut myself a 75 mm HT pipe to match. So all containers are connected and water
can be filled in for the first time. It’s also a good way to check for leaks. Now the water has reached the pump. That means we can plug it in and see how it
works. And it looks good. Filling it up is going to take a while, so
in the meantime I’ll prepare the bio chamber ventilation. For now I use a small aerator pump. However, the two outlets are so small that
they are not heavy enough. I weigh them down with a net and some stones
so that they stay in the desired spot. They come down into the bio chamber and bring
oxygen into the Hel-x. In addition, the rising air ensures a more
even flow of the water through the hel-x. Unlike a moving bed filter the hel-x material
will remain inactive. This allows the rain barrel to be able to
hold such a large capacity of biomaterial, which in turn will improve the filters overall
performance. The aeration seems a bit too small to me,
so I will invest in something bigger in the future. Now I can get the filter brushes out of the
pond and put them in. In the brush filter, I put two 90° elbows
on the wall bushings from the inside. So the water is deflected upwards and the
dirt can settle better on the bottom. I also add some natural pond water to the
new system. Maybe it will bring in a few more beneficial
bacteria. Now I also got the biofilter material. The nitrifying bacteria are supposed to settle
on the Hel-x. But do not throw in everything yet, because
there is still something missing. In this small piece of pipe I put a 13 Watt
UVC tube light on the inside. This works well with the suction cups on the
smooth HT pipe. At the end I attach a 90° elbow. The whole thing is now put on from the inside
into the wall bushing. The elbow optimizes the flow of the Hel-x
material and the UVC lamp reduces the germination pressure in the system. The only downside is that the HT pipe is not
UV resistant and needs to be replaced at some point. But the lamp sits well in the center of the
pipe and the water is irradiated evenly as it flows by. This way it is really cheap to operate such
a useful UVC lamp. Now I fill in 120 liters of Hel-x. I decided to use the thicker 35 mm Hel-x material
as it has good flow characteristics in a static structure. Now the system is ready and there are no signs
of leaks from the pipes. Well, we can put in some fish now. I have some koi from my natural pond here
that are going to be sold, so they will only be in here temporarily. The basin will also serve as a quarantine
and observation tank in the future. In the finished system, the water will now
run as follows: From the 700 liter tank, the water flows out the two 50 mm drains into
the 75 mm pipe and then into the 90 liter brush filter. Here, the water calms down and suspended particles
can settle on the bottom or on the brushes. Over time, bacteria settles here, which decompose
the coarse dirt. A clear advantage of this gravity system is
that the coarse dirt particles are not first shredded by a pump, but are allowed to settle
down and not additionally cloud the water. Then it goes out again at the other end, namely
the water drains off from above, so that the dirt can settle at the bottom really well. You can adjust the water level with a piece
of pipe, which you simply shorten to the desired length. When I want to drain the brush filter, I simply
place two longer pieces of pipe onto both elbows to stop the water flow. Then the filter can be easily and quickly
drained with the ball valve. When the time comes I can show you how to
clean the filter in another video. Then it continues into the 200 liter biofilter,
past the UVC lamp and then through the Hel-x. The thicker Hel-x allows good aeration, which
provides an even water flow through the material. I might want to optimize this in the future
with a hole trickle plate. During operation, the lid should always remain
closed, because the nitrifying bacteria are sensitive to UV light. The pump is at the bottom and its casing keeps
the Hel-x from being pumped out. It transports the water from the bottom of
the bio chamber back into the tank, where it provides a nice flow. As a result, dirt particles do not settle
easily on the bottom and are slowly transported to the side drains. The rectangular tank is not ideal and a bottom
drain in the middle might probably work better here. I intend to install a second aerator in the
tank just to be on the safe side. The rule of thumb states you should aerate
approximately 2 liters of air per minute per cubic meter of water in the system. All pipe connections look secure so far, which
can of course be secured with screws or clamps. But first I am very satisfied with my small
indoor tank and hope you liked this video. Through the HT pipes, the system is flexible
and I can always change something around later. Normally, the filter should have a size of
10% of the tank. The filter capacity is therefore very large,
so I could easily expand the system and add a larger tank, for example. Then there will definitely be a new video
coming out, so subscribe to my channel. I’m always happy to receive good ideas and
suggestions, so feel free to leave a comment. I wish you much success with your projects. Thank you for watching and see you next time,
I’m Carl the landscape guy.


  1. I made an indoor system with two 275 gal IBC totes, cut the tops off, pump from each of the totes to a 70 gal tank with expanded clay as my filter, then gravity feeds back to the two totes. I use cam lock and flex pipe between the 70 gal tank and the two totes and the totes already had ball valves. Added some air to each tank x 2 for back up. Just need a way to suck the crap solids off the bottom better, maybe just use my shop vac? The fish seem pretty happy, big blue tilapia that are 2 1/2 years old and up to a few lbs.

  2. I do not recommend you use those slip on o-ring connectors. The weight of the water on those 3 inch tubes may well bring that down. If it is for a drain tube with minimal water rush its ok but not for pumped water especially in 3 inch caliber. You have rubber clamped connectors for that in order to maintain the flexibility of disassembling all. I did an aux tank with a 600 gallon intex pool and the filter was made with a 25 gallon trash bin with a vortex setup and worked a treat with just foam and a decanting vortex on bottom. I even used the intex pump with no filter wich is really low energy use.

Leave a Reply

Your email address will not be published. Required fields are marked *