5 Reef Tank Myths: That We Still Believe

I think we’ve all probably setup a tank with at least one of these in mind! Here are a couple of Reef Tank Myths that we still believe:

MYTH #1 – We need 1-1.5 pounds of reef rock per gallon of aquarium:

The idea here is that a certain amount of rock is required for successful denitrification. However, the ‘pounds per gallon’ is a little misleading. For example, five pounds of car washing sponges take up a lot more room than five pounds of bricks. Five pounds of very porous light weight rock will take up more room in your tank than five pounds of dense rock. More porous rock will offer better denitrification. So in fact, the lighter the rock, the better!

The metric should really be a combination of overall volume and porosity (relative weight/size can be used to determine porosity to some extent), as you need to leave space for adequate water flow, coral growth etc. Pukani rock offers a great combination of size, shape, porosity and is ideal for denitrifying bacteria.

Lighter rock can also be easier to aquascape.
Pukani dry rock is very light and porous and lighter rock can also be easier to aquascape.

MYTH #2 – We need ‘x’ lighting watts per gallon to keep corals:

This myth still rules many reef tanks. Stronger lighting can produce faster growth and increase colouration in some corals. But it is not the only contributing factor. Corals can acclimate to a wide variety of lighting conditions. PAR or Photosynthetically Active Radiation is more important than the number of watts your lighting runs on. For example, low watt LED fixtures can put out a lot more PAR than high watt metal halides, even burning corals in some cases. Adequate lighting is a good start, but do plenty of research on the corals you plan to keep and think carefully about placement, lighting and flow together.

For example, you might place a house plant right under the window to make sure it gets enough light. But then it dries out, loses all it’s leaves and shrivels because it was sat over an air vent and was getting bashed every time someone shut the curtains. It would have done much better if it was placed a little further away, where it would be free from curtain damage and direct air flow, even though it received less light.

SPS generally require much higher lighting.
SPS generally require much higher PAR but can do well under a variety of different light sources.
Myth # 3 – Bigger reef tanks are easier to care for:

This myth is famous because of the old adage “the solution to pollution is dilution”. It’s thought that if a creature comes to it’s demise in a large tank, it’s decay won’t pollute the tank so much that the tank crashes. You may have heard that it’s easier to keep a larger tank stable because of smaller fluctuations in tank alkalinity, phosphate etc. While these are true to a point, this can be rather misleading. Larger tanks can hold more livestock and therefore require larger water changes. This means larger water storage containers and mixing stations, and more things to clean and maintain.

There is also more glass to keep clean and often more rock work too that may need a lot of time and attention if algae or other issues arise. Larger tanks do offer some advantages, but they should be weighed against the time you have set aside to properly care for the creatures they house.

Myth # 4 – Smaller reef tanks are harder to care for:

It’s true that smaller tanks can have greater fluctuations of alkalinity, phosphate etc, because of the smaller water volume compared to coral/fish bioload. This can be difficult to manage if you don’t plan ahead. For example, a large algae-eating Margarita snail could quickly starve and die in a 5 gallon nano reef, polluting the water column and quickly spiking ammonia and phosphate levels. Small tanks usually mean small inhabitants are best.

With the addition of automated dosing pumps there is no reason why stability cannot be achieved in even the smallest reef tanks. Water changes also become much easier and take less time the smaller the tank gets. Smaller tanks mean less work on water changes, but could require more time testing and checking water parameters to keep things stable. Larger tanks can be a little more forgiving on the testing side of things.

Smaller tanks often require more testing to keep things stable.
Smaller tanks often require more testing to keep things stable.
Myth # 5 – Buying the best means success:

We’ve all heard the line, that to be successful you need to buy the best lighting or skimmer you can afford. Or whatever the product may be. However, even reef keepers with the best products available have let their phosphate get out of control and experienced algae outbreaks or other negative effects. Many successful reef tanks run lighting or skimmers with low initial costs and then upgrade later on, as and if they need to. One of the most successful tanks I ever had was a 3 year old 40 gallon with no skimmer at all! Both LPS and SPS thrived and grew very well. Success ultimately comes from having a well researched and thought out plan.

The author's 40 gallon skimmerless reef tank.
The author’s 40 gallon skimmerless reef tank. Photo taken around 2010.