With marine aquariums the general view is that bigger is better. If it fits the budget, the largest aquarium possible is often the way to go. There are several reasons.

Firstly, large tanks have large water quantities. The larger the water quantity, the better the water quality. It takes a lot longer to pollute a large tank. Water conditions tend to change less rapidly and hence, don’t stress fish as much.

Secondly, larger tanks allow hobbyists to keep larger fish. If keeping large fish doesn’t appeal to you, then a larger tank would enable you to keep a greater number of smaller fish. There is nothing worse than wanting “that fish” and finding out your tank is too small. In any case, you will not be able to keep “jaws”, but a large tank would accommodate most marine life available in aquarium shops.

Finally, larger tanks allow fish to “spread out”. When keeping fish confined, you increase the chance of conflict and disease. Having a larger aquarium allows some personal space for fish, along with giving them enough room for a territory of their own. If fish are constantly battling then they run a high risk of wounds and infection. They also look unattractive when half their fins and scales are missing!

In my opinion, if you have the room, save for a larger tank. More often than not, hobbyists start small and end up buying big anyway. If it is possible, consider purchasing a tank at least 6ft x 2ft x 2ft. This size tank will hold a large quantity of water and is still quite movable. If you are planning to build a tank larger than this, here are some things to consider.

1. Glass thickness. Don’t let anyone tell you 10mm glass is strong enough to hold a vast quantity of water. A tank that is larger than six feet would require 12mm glass. Glass does flex! It will flex quite a lot actually. If the glass flexes enough, the sealing compounds holding it together will fail. Trust me, you don’t want this to happen. An 8ft sheet of glass with 1000 litres of water behind it can kill. Consult an expert if designing a custom tank. Don‘t rely on one person’s view ask a few, this will give you a general consensus.

2. Appropriate reinforcing. Even thick glass should be reinforced. Especially if holes have been drilled for trickle filter systems. Again, check with an expert and explain everything you wish to do before the tank is built. It is important that the tank builder knows your full intentions, that way they can reinforce appropriately.

3. Correct Sealants. There are many different grades of sealants. A professional tank builder will use only the highest-grade sealant available, but it pays to check. If there is an option go one better. Why not? It’s there for the life of the tank. J ust remember, it’s the part under the most pressure and if it fails…. well, that might not be pretty.

4. Able to be moved. An 8ft tank with 12mm glass is heavy! The bigger they are, the harder they are to move. I had an interesting experience with moving an 8ft tank. Six people, including myself, went about moving a tank in through a house. When it came to a final doorway, it allowed only three people through. This made things a little hard. Let’s just say there were three very sore backs and a very lucky tank! Needless to say that tank is now a permanent feature of that house.

5. Filtration. If you are intending to use a trickle filter system, then you must build skimmer boxes inside the tank. Skimmer boxes and return holes must be made and adequately braced. The height of the skimmer boxes also will have to be decided as this determines the water level inside the tank. If you are like me, then you would want the water level in the aquarium to be as high as possible so it looks full at all times. It doesn’t really matter though, as long as you consider this before the skimmer boxes are built.

6. Cleaning. Large tanks require cleaning while still in operation. Unlike small aquariums, large tanks cannot be emptied, taken outside and hosed. They require the hobbyist to hand clean the inside of the tank without removing the fish. Although there are magnet cleaners on the market, check the maximum glass thickness on which they will work. If the glass is too thick, then the magnetic attraction is too weak and the device will continue to fall off, making cleaning slow and frustrating.


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