A New Saltwater Aquarium – It’s Exciting But Check Running Costs!

** Editors Note **

Well 2007 is now over and we are at the start of a brand new year – let’s hope that this year is as good as the last.

Here at Aquarists Online we are excited to see a new year arrive. We have so many plans for the site, so many areas which we hope to grow and of course we hope to provide useful, informative information to you on a daily basis. The site traffic is increasing on a daily basis, our forum is getting busier and busier, we are always on to the lookout for tools which will help you and our aim is simple:

‘To assist the beginner to the saltwater aquarium hobby so that the aquarium will be a success’

We hope that you stay with us as we grow – hopefully into the largest saltwater aquarium community on the internet.


Obtaining a new [tag-tec]aquarium[/tag-tec] is exciting. The aquarist becomes immersed in it (no pun intended!) considering aquarium equipment, fish, and corals etc. There is a clear vision of a beautiful healthy reef tank which is stunning to see.

With proper planning this can all become reality. The cost of setting up a marine aquarium system is not low, but in time the investment will pay dividends in enjoyment. Or will it?

The aquarist when planning is very careful with research into the correctly sized and best protein skimmer, proper lighting, correct construction of a deep sand bed, correct stocking remembering compatibility etc. One thing that is often overlooked is running costs. There is only a view to completion of the construction which is understandable. There is however a danger to the ongoing health of the aquarium in general if running costs are not considered.

The running costs should be investigated before the final size of the aquarium is decided. It is incorrect to obtain an aquarium as large as will fit into the allotted space without thought. A bigger aquarium needs more water, more heating, and more lighting. Yet this is what so often happens, the aquarist then purchasing equipment to suit.

What should happen is that the aquarist decides the largest aquarium that will fit (if the largest is what is desired). Then a calculation is made of the indicative ongoing running costs before a final decision is made.

The first calculation required is to estimate the net gallonage of the aquarium system. So multiply the aquarium length by the height (height is measured to the water level) by the depth (front to back), these measurements are in inches. There is no need for absolute accuracy but ‘fairly close’ is the aim. Having obtained this number, divide it by 231. The resulting number will be US gallons. (Remember that if the system is to include a sump then the same calculation is required for the sump itself. Then the main aquarium and sump gross capacities are added together.) The gross capacity of the aquarium system has been obtained, but the aquarist requires the net figure. Therefore, reduce the gross capacity by 15%. This will probably be an underestimate, particularly for a reef aquarium, but will suffice. (The gross capacity is reduced to allow for the displacement caused by rocks and sand.)

Now that there is an estimated net capacity, the aquarist knows the amount of dry salt mix that will probably be required for the initial fill. However, here the concern is ongoing running costs. The recommended routine water change is 10% per week (at least in the early months). Therefore 10% of the initial fill salt mix is going to be required weekly. The aquarist can estimate how long any particular size package of dry salt mix will last, and therefore the ongoing cost of using it.

The major cost of running a marine aquarium after it has been set up is electricity. Even those who live in sunny and warm climates will probably need to run chillers (seawater coolers) and also lighting. However, it is easy to calculate the guideline cost of electricity before the aquarium is even set up. If the aquarium being considered is ‘reef ready’ then all the electrical equipment is available to be listed. If the aquarist is setting up an individual system, then a list of the required heaters, lights, pumps etc will be needed. This requirement will exist anyway before any purchase so there isn’t any additional work.

Working through the list of electrical items, write down the power of each item. This number will be given in watts (W), and will most likely be on the piece of equipment itself, or on the instructions that come with it. List the wattage for all electrical items.

Before the calculation is done, two of the numbers on the list need to be amended. This is because the heaters (or cooler) and lights will not be on all of the time. So the wattage that has been noted for the heaters (or cooler) and lights can be reduced by 50%. This will not give a fully accurate figure, but will be close enough for this costing exercise.

Having now got the final wattage figures, add them all up. Divide the number obtained by 1000. (One kilowatt (kW) = 1000 watts.) This will give a number representing kilowatts. It most probably will include a fraction of a kilowatt.

From the last electricity bill find the cost of a kilowatt. Note that this cost is usually per hour, that is the cost of a kilowatt used per hour. Don’t make the mistake of multiplying the number you have obtained by the kilowatt cost, it will be horrific – and wrong! For example, say the number obtained from adding up the equipment wattage is 750, then 750 is ¾ of a kilowatt. If the cost per hour of a kilowatt is (lets make it easy) 12c, then the hourly cost will be ¾ of 12.

Having worked out the hourly electrical cost of running the system, it is easy to work out the daily cost (multiply the hourly result by 24), weekly cost (multiply the daily result by 7), monthly cost (multiply the weekly result by 4) and so on.

Now the guideline running costs of the aquarium can be seen. Add the electrical and salt costs together. There are other costs, such as new lighting tubes/bulbs periodically, filter media – if used – periodically, fish foods, additives etc. However, the major indicative costs are known, and the aquarist is not going to be shocked when these costs are realized.

It was said earlier that there is a danger to the ongoing health of the aquarium if these running costs are not considered. Why is this? It is because if the aquarist’s budget is always under pressure it is more likely that routine water changes and other aspects of [tag-tec]aquarium care[/tag-tec] and [tag-tec]aquarium maintenance[/tag-tec] will be reduced in order to save on the cost of dry salt, and/or lighting bulbs and/or tubes will not be changed when a change is needed etc. If this is the case, problems may well arise which will reduce the aquarist’s enjoyment, which in itself can cause problems.

If the suggested check is done it may well be that the largest aquarium that will fit will be fine. However, if not, obtain a smaller one and help guarantee future success.

  1. hi guys

    I have done some calculations includong water, salt, additives,livestock replacement, bulbs and equipment replacement

    I ended up with about $35 per week for a 3 x 2 x 2

    I think it is a bit high. Do you have any other accurate running costs for a similar aquarium



  2. I have an aquarium similar to yours in size, lit by fluorescents (soft corals), no chillers just heaters. It costs around $9/$10 a week as far as I can make out, excluding additives, sea salt, new tubes, filter media etc. I would find it difficult to be accurate. Yours does seem high though. The problem is everyone uses different equipment which adds differing amounts to the running costs, some do more and/or bigger water changes, some live in cold areas so heaters are on longer, in warm areas chillers are used but how long are these on? In different areas electricity costs vary, and companies vary in their charges. Itis very hard to quantify the actual cost of running an aquarium. The 1/2 on 1/2 off for heaters and lights is not accuratre either, but just gives some sort of base.

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