Chapter 3 - Tank Size and Filtration

Before you even think about buying a tank. There are a hundred things that you have to consider above the hundred basic things such as size, cost etc. A larger tank is easier to maintain simply because the water in a small tank doesn't take every long for it to foul up because there is less water to foul, whereas a larger tank takes longer to foul because there is more water to foul. Logical.

Think about how many discus you want to keep. The general rule is 10 gal per 1 adult discus, 15 gallon if it is planted and/or community tank. Less if they are juvenile but since this is my show tank and the discus are most likely going to live there their entire lives there, I will need to think in terms of adult discus. Of course under stock is better than perfect stocking and I will aim to under stock my tank. You should never buy discus one by one. They will do far better in at least pairs or more and will be much more comfortable in the presence of other tank mates. Generally if you want to have at least one breeding pair out of your starting brood then 6 discus is the typical amount you should start with for the best chance to have at least one breeding pair. If you are very lucky you may have 2 breeding pairs and if you are extremely lucky you will have 3 breeding pairs. I will most likely opt for 6-8 juveniles to start with, then end up with a total somewhere between 10 and 14 adults.

Water Quality is the key

One of the key ingredients of a successful tank is water quality and by quality I don't just mean clean and devoid of contaminants and pollutants. I mean quality as in stable. Water that you can reproduce in large volumes over and over again, time after time, day in day out. The more you do to change your tap water parameters, the more chances it will fluctuate and fluctuation is what stresses discus most above all else. Remember that we don't look after fish, the fish look after fish. We look after water, after all we are aqua-riasts not fish-iasts! If you look after the water and make sure it is extremely stable, clean and well maintained, the fish will look after themselves.

One way to keep water quality at high levels in your set up is filtration. I will not go into what types of filters are around but will talk about the types that I would consider using in my set up and why. Simply a matured filter will allow you a "buffer" of at least a few hours or days even, to curve parameter swings in your water. For instance when ammonia starts to build up due to uneaten food, fish waste etc (which it shouldn't do if you do regular water changes and are running cycled, adequate filtration) the filter can do a lot to neutralize this ammonia build up biologically and it will simply take longer for the ammonia levels in your tank to reach extreme and harmful levels. You can run a tank successfully without any filtration at all and simply rely on water changes only, but you won't have this benefit of a "buffer". This is also true of uncycled filters. Basically an uncycled filter has no bacteria to eat up ammonia and nitrates and will only do mechanical filtration (removing large particles in the water). An uncycled filter is pretty much the equivalent of no filter at all! Generally filters have a lot more benefits than that and it is far more worthwhile to run a cheap air driven sponge filter than not to and risk it.

When planning for filtration, aim to move about 5 times the total tank capacity through the filter every hour. Filter size and media are also something to consider as well as some media are more effective than others, requiring a smaller volume of media to be effective. The best type of filtration by far is a combination of both biological and mechanical filtration. For grow out/quarantine/breeding tanks by far the best type of filtration is a simple air driven sponge filter as it is extremely cheap, easy to maintain, works very well and doesn't generate a great deal of water current yet providing enough aeration. I also like power sponged like Fluval4 Sponges or Eheim 2010 sponge filters. They work very well, are extremely quiet, the speed of the power head is adjustable and the running costs are very low.

The Wet/Dry Filter System

Wet/dry or trickle filters is by far the best option for my 180gal. It is cheaper than extremely expensive power filters and canister filters that suit my tank size, and if you are at least a little handy they are dead easy to make. It can also be cheaper to run requiring only a pump and cheap media such as bio balls, filter wool and/or sponges. The wet/dry system can go longer between cleaning and will require very little maintenance except for a rinse of certain media periodically, cleaning prefilters and to removing larger organic material build-up. It is also a very good option for larger tanks in it's ability to cycle large amounts of water. To match this using canister filters or other power filter types would require very large, very expensive, elaborate filtration combinations that will end up costing a lot of money in equipment and energy consumption bills. This type of filter acts as both biological and mechanical filter and adequately oxygenates the water due to the vast amount of contact between the water and air and the generation of turbulence as the water trickles over the media before collecting in the sump or holding section of the filter. This water is then heated and pumped back to the main tank which fills the tank over and the water then flows into an overflow box where the water is gravity fed back into the filter again. Also equipment such as heaters can be placed in the sump as apposed to the main tank which looks nicer and works more efficiently; less power is required to heat up the small amount of water in the sump than the large volume in the main tank, that’s the theory anyway. This of course is only effective if you have an external thermostat to control the heaters that can be located in the main tank and connected to the heaters in the sump.

For this type of set up I will be looking into an overflow system, perhaps even built into the tank design itself, located in one corner and 1 to 1.5 inch with a hole drilled at the bottom of the tank to allow gravity fed access to the wet/dry filter in the cabinet below. The overflow works by having the a pump that is located in the sump of the filter, pump water back into the main tank. Another good feature about this type of design is the failsafe. When the power goes out, the pump will stop working and there will not be enough water to overfill the tank and the system basically shuts off. There are a few things that should be noted in the event of a power failure however;

1) if it the power is off for extended periods of time and your filter is swamped with water, the oxygen loving bacteria culture that grows and thrives there will be starved of oxygen and they will start to die off. When the power comes back on again this could mean you are pumping poison in the form of increased ammonia and other chemicals back in into the tank! This can be controlled by replacing the water in the filter, rinsing the media in the filter (not in tap water but in warm tank water) and doing a water change. This will make sure that the stagnant water will not get pumped back into he tank. Also your filter can be designed to incorporate a layer of filter wool that the water has to run through after the bio balls chamber to collect as much of the chemicals as possible. This will work to a certain extent but I still recommend replacing the water. Hopefully this may never happen often for me (Sydney electricity is quite stable).

2) The sump of your filter will need to be greater than the excess amount of water flowing through the tank as any one time. Otherwise when your pump stops, the overflow water falls into the filter and you get a very wet floor!

An advantage of wet/dry filtration is the ability and ease of customization of filter media. Peat and activated carbon bags can simply be dropped into the filter in the right compartments when needed and can be removed easily when needed.

I will also think about backup systems like a hang on the back (HOB) power filter like an Aquaclear 500. The reason for this is because I have owned an AquaClear for a very long time and it has been a very good companion for emergencies, hospital tanks, quarantine tanks etc. The most import features of this type of filter is that it is very easy to clean/maintain/customize media, it works very well, and above all it is mobile (of course this does not mean you move filters between tanks without adequate sterilization). Another system that I will consider is a simple sponge filter that hangs via suction cuffs on the inside of the tank, or sits on the bottom of the tank (Hydrosponges) and is powered by an air pump or power head. This system I will most likely incorporate into a quarantine tank and can also be used to rear fry. It is also very cheap, works well and fry friendly.

Water Changes - The best insurance for water quality

The best way by far to keep your water quality at a high level, that works better than any gizmo or gadget that you can buy, is regular water changes. I cannot stress this enough. Water changes is by far the most cost effective and of most benefit to your tank and fish. This is why I advised earlier to strategically work out a way to make lots of well aged tank water, quickly and in large quantities. Your fish will do better in regularly changed water than water that is seldom changed but highly filtered. When selecting the size of your tank, be aware that on bi-daily basis at least you will need to do a water change of some amount, even if it is only to suck out fish facies or leftover food. The more the merrier. With larger changes you will need to change 25%-30% of the water in your tank and may include preparation of the water and storage of the water beforehand. For my 180gal tank, 30% of this would work out to be at least 54 gallons, more would be better of course. I will need some sort of large barrel or plastic garbage bin (bought new, and used especially and exclusively for this particular task). You may also need another bin or barrel to store the old water before it's disposal (unless of course you are as lucky as me to have a laundry drain or garden lawn within reach of a hose). Also you may need this old water storage barrel/bin for certain reasons such as filling up hospital tanks and etc. It is not absolutely necessary but its something to think about if your circumstance warrants.

You should now work out a strategy on how you are going to do regular water changes. Anything that you can do (such as using larger bucket, higher capacity pumps etc) which will save you 2 mins here or 5 mins there will save you copious amounts of time in the long run. Besides, the more tedious a task, the more likely you are going to be turned off doing it on a Saturday or Sunday morning, don't worry, I know, I am human too! Also there is the issue of cleanliness. By this I mean making sure your buckets, hoses and nets are kept clean, away from sunlight, deodorants, preferably in a dry state and most importantly not used for any other reason than for your fish! Also remember to wash your hands thoroughly, keep your nails short and clean (I mean it!) before and after you dip your hands into your tank. If you have seen the tape worms and other nasty parasites that your fish harbour, believe me you'd know what I am talking about!

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