Seth Deghaye: DIY Cichllid Aquarium

Introduction

After a couple years of keeping a small aquarium with mollies and guppies, I decided to move onto something a little more challenging and interesting. Surfing the web helped me discover cichlids. These fish are much more interesting than guppies and mollies, however, their requirements are a little different.

Being based in Pretoria, South Africa, I had access to a local fish store that stocked a decent range of cichlid species. I spent several hours researching these fish and decided that I wanted to have an African Cichlid aquarium. As a South African, I decided the only option was to have an African Cichlid aquarium as I'm not keen on things exotic. Besides, African Cichlids are really interesting.

As a start I needed a much larger tank. My little guppy tank was a small 50 litre; while a decent cichlid tank needs to be at least 200 litres. I had previously built a 150 litre planted aquarium a few months ago, but that one was not going to be suitable, so I decided to increase the size of that tank and build a decent home for some cichlids.

Follow this blog to find out how I designed and built this aquarium and perhaps this will pursued you try this kind of project yourself.

I'm mostly finished the project, but there are still a few things to finish in the next week or so, but for now, I'm happy to share my progress to date.

Planning & Design

I never dive straight into making something without planning and thinking through everything. Not everyone is like this, but it does help with a project like this to do some planning so you don't fine you need to make changes half way through.

For a project like this I like to have a visual picture of what the final product is going to look like. For this project I used Google Sketchup for the first time. I found this tool to very helpful when working on the design as I could see how things were going to look and fit together. On the right is a snapshot of a design I was working on for the aquarium and stand. I was initially thinking of making an all wood stand, but changed my mind as I had some steel and was interested in trying out my hand at welding. I inherited the welding kit from my wife's grandfather, and had not really used it for anything substantial yet. The design for the metal stand (snapshot on the left) was done separately and without the tank to save time.

My design included the plumbing and filtration so that I could plan the positioning of the pipework and quantities of the various parts required. This helped me plan my purchasing so I did not have to do repeat trips to the store.

The Aquarium Design Overview

The tank construction material

Due to the relatively high cost of Perspex (Acrylic), I chose to build my aquarium from glass. I wanted a tank that had a fairly large front view, so I decided to try make the tank at least 60cm (2 ft) high. I was initially being very ambitious and trying for a 1.8 meter (6 ft) long by 60cm (2 ft) deep tank, but the cost of the glass was going to be a little steep, so I scaled this back to a 1m long tank. As I already had a tank that was 1.0m x 0.6m x 0.25m, I would be able to use the front and back glass sheets from this tank to save on glass purchasing for this new tank.

Glass thickness is an important factor when building an aquarium. There are several tools available on the web for calculating the thickness of the glass required. I used http://www.theaquatools.com/building-your-aquarium and chose a safety factor around 3. This is a little low for some, but I was prepared to use top bracing to increase the safety factor. I ended up using 10mm glass for the front and back panels, 8mm for the side panels and 6mm for the base. I was able to use thinner glass for the base as I was going to use 20mm plywood between the aquarium and the steel stand and the steel stand was designed to provide significant strength too.

Aquarium Support

The tank stood on a 10mm polystyrene sheet, on top of a 20mm plywood sheet on top a steel stand.

Lighting

I already have some spare lights and ballast for T5HO lighting. I planned to use 2 x 39W daylight bulbs, but I will experiment with this once the aquarium is complete.

Filtration

I liked the idea of using a wet/dry trickle filter which will be housed within the stand underneath the aquarium. This was also in an effort to control the costs as I could build a high volume filter for relatively low cost.

As far as bio media is concerned, I wanted to use something easy to access and cheep to buy. My wife does sewing as a hobby and had some polyester batting in the cupboard. I realised that this material has very fine polyester stands which are fairly loosely packed together. This should provide high surface area for bacteria growth while allowing free air flow to fee oxygen to the bacteria. The success of the medium will be judged in a few months time.

To aid effective filtration I wanted to ensure I had sufficient circulation within the aquarium so that there are no dead spots where debris and waste can build up. I planned to include a power head attached to some under gravel tubing and small jets that directed water flow to potential dead spots.

I also planned to have an overflow system that collected water from the bottom of the water column, which is where most of the debris and waste ends up. This would help remove more waste and debris, keeping the aquarium cleaner and healthier.

Aquarium Contents

I wanted the aquarium to look as natural as possible to keep a natural feel. The substrate I chose was a fine gravel I found at a local garden nursery. It included many different rock types and colours, but had an overall dark appearance. The gravel pieces were also well rounded (probably from natural water erosion) so there should not be any rough, sharp edges for the fish to injure themselves on. You can see the gravel in the pictures of my cichlids at the bottome of this page.

I also wanted the rear of the aquarium to have a natural looking "rock shelf" to be in line with some of the natural environments in the African lakes. I considered manufacturing my own fake background, but I was not keen on all the work and conditioning required for this type of structure. I decided to use natural stone attached to a supporting structure as a background with loose rock at the base.

Finishing

Wood panels then attached to the top of the stand so that they cover the wood and polystyrene layers and the glass base. The top of the wood panel will line up with the top of the substrate in the aquarium. The same wood will be used to make the hood. The hood will be joined to the base by wooden pillars at the rear of the tank sides. These side panels will also extend beyond the rear in the aquarium to help hide the plumbing and wiring.

The Build

I started the build with the aquarium stand so that I had a suitable working surface for the tank assembly.

Aquarium Stand

Designing the metal stand took a little effort. I wanted to ensure I had sufficient structural strength to support the weight while minimising the cost of material. I did some engineering design work to calculate the loading capacities and the deflection in the support beams. Metal will deflect under load, but you don't want too much deflection as this will place high stresses on glass (which does not cope with flexing as well as metal). I went with a design that allowed about 0.5 mm flex in the long support beams. This small deflection will be compensated for by the polystyrene layer under the glass base. I obtained useful information on the structural parameters of steel from http://www.steeltubeinstitute.org. If you want to see my calculations, send me a request directly.

The build went fairly well, and according to plan. I managed to complete the stand construction in 24 hours, and the painting took a couple days to complete. I used a Hammerite Paint on the structure to keep a natural metallic look. I prefer using this paint for metal work as it is easy to apply and does not require any primer.

The Glass Tank.

I've had a little practice with this task already, so I was not worried about this part too much. The difficulty is working with the large, heavy pieces of glass. During my first attempt, one of the side pieces fell, but did not break (luckily). I managed to do the task alone by supporting the first panel against a cupboard to keep it upright until I could attach the other panels. With the glass pieces cut to size by a local glass merchant, the assembly only took about 30 minutes.

I left the assembled aquarium to cure for 72 hours to ensure the silicone had fully cured before performing a water test. The water test was run for 48 hours.

I then drilled the back panel for the overflow system. This was a new task for me, so I practiced on a few spare pieces of glass to get the technique right. I used a diamond tipped hole saw with my cordless Bosch drill set at about 500 rpm (the recommended drilling speed) It took some time as I did not want to crack the glass. I should had drilled before assembling, but I hod not yet decided whether to drill through the base or the rear panel. This was more risky, but it worked out fine in the end.

I followed the aquarium build direction given on http://www.austinglass.com.au/aquariums.html, but there are many sites out there with instructions on this task, so I won't add to them.

Filtration and Plumbing

I planned to use my existing 50 litre aquarium as a sump for the filter, but as there are currently fish in this tack, including some small cichlids (pics below), I used a temporary filer setup using the some of bio media that was going to be used in the final filter. Using the actual bio media in the temporary filter during the cycling process allowed me to build up sufficient bacteria in the media before I convert to the final filter. For the temporary filter, I used some plastic containers we had in the house already.

The filter includes the following; mechanical filtration (10mm fine foam sheeting), bio filtration (Batting material) and then chemical filtration (activated carbon). Deciding how much bio media to use is a little tricky, and it depends on the media you use. I went with 5% of the aquarium volume, about 17 litres. This would easily be achieved in my 50 litre glass tank.

The filtration is completed with a 3000 l/h submersible pump, which should achieve 2500 l/h in its position under the aquarium.

The plumbing currently consists of PVC piping and fittings obtained from my local hardware store (Builders Warehouse). This was readily available and easy to work with. I do plan to change this to polypropylene piping to avoid the risk of toxic chemicals leaching from the PVC.

I will later include pictures of the plumbing layout used to achieve the overflow from the bottom of the water column.

Cycling

Once the plumbing and filtratioin was in place, I put in the substrate and some rock I obtained from the coastline during my recent trip to Durban (The rock was thoroughly rinsed and soaked for a couple weeks to remove any toxins that may have been present in the sea water). The tank was filled, a few plants from my existing tank were planted and some substrate and filter media were transfered from my existing aquarium to provide biological organisms to start the cycling process. I then transfered a couple algae eaters from the existing tank to provide a source of ammonia to initaite the cycling process.

After a week I then started the process of transferring the fish from the existing aquarium to the new one, at a rate of 1 or 2 fish every other day, so as to not overload the new aquariums biological system too much. The fish are relatively small, so I used a fairly high rate of fish addition. I'm not sure if this is the wisest thing to do, but we'll see how it goes. At this stage, I have transfered 12 fish to the new tank, and should be done in a couple weeks.

Background

Using natural rock as a background is a little difficult. To prevent a rock fall and severe damage to your aquarium, I chose to adhere rock to a plastic lattice which could then be attached to the rear of the aquarium and proped up at the base with loose rock.

These pictures show one of two original plastic crates I found near a shopping centre that were thrown out due to excessive damage. After cutting these to size, I have two panels that are going to become the foundation of my rock background.

You can see some rock attached to a plastic panel. I used and locally produced epoxy adhesive that can be used in boat manufacture, ABE Epidermix 372. I tried these few rocks first and tested the strength of the bond after 2 days. I cannot easily pull these rocks off the panels, so I'm confident they will not fall off in the aquarium.

This is still in progress, so once the panels are complete, I will post another picture of the completed job

Lighting

I'm currently using a hood from my previus planted aquarium, which is fine as a temporary hood until I build the final structure.

The hood is still to be built, but I have manufactured some DIY reflectors. I used a 850mm long peice of 50mm PVC piping, cut it in half lengthways and lined the inside with aluminium foil. I'm sure these will not purform as well as the professionally manufactured ones you could purchase, but mine cost me about R15 to make, rather than about R300 to buy. I'm sure they will work almost as well.

Pics to follow soon.

Still to be done

At the moment I have a working aquarium, with half my fish now transferred from my older aquarium. It does not look great yet as there is no background in place to hide the plumbing and create a more natural look.

Once the backgrounds are completed and in place, I will complete the wood work to finish the aquarium more professionally.

Once all the fish are transferred, the filter will be completed and all substarte from the old tank transferred to the new tank.

I also want to improve the plumbing a little as the pipe openings at the bottom are allowing smaller fish to swim into the pipe, thus ending up un the filter. This is not a problem for now as there is siuffecient water above the mechanical filter to keep the fish alive. I just check on them in the morning and evening to rescue any that have found there way into the filter.

The project should be complete by early October.

Pics of my Cichlids

Below are pics of my cichlids in their current home. I have tried to ID them and give the correct species name below each picture.