Reef Tank Maintenance . Keeping it Simple and Efficient

During the last few years, the technology available to facilitate the work of hobbyists has experienced an important boom. Technological advances have been transferred from the laboratories of scientific institutions, public aquariums and aquaculture companies. There is a transfer of techniques in the fields of biology, physics, chemistry, hydraulics or electronics. Much of the equipment available on the marine aquarium market is of impeccable design and optimum performance. Control electronics has been progressively gaining ground, forming part of equipment that previously did without it, e.g. circulation pumps, calcium reactors, LED lamps and alkalinity measurement and control systems.

However, technology itself is no guarantee of success, because it cannot replace the knowledge and experience of the hobbyist. An over-technification of the aquarium adds additional complexity that needs to be managed. There is a risk that the aquarist will spend too much of his valuable time operating the devices that were supposed to simplify his routines. Technology is a tool and therefore must add security and decrease complexity in maintenance. It is possible for a new equipment to demand additional efforts without an objective return. This principle applies to any maintenance practice or technique.

The principle of maximum simplicity should dominate the strategy of hobbyists approaching the world of reefkeeping for the first time. The maintenance of a reef aquarium can be made as complicated as you like. There are countless parameters that can be monitored, every kinds of additives to use, colorimetric measurement tests, digital, electronic probes, infinite varieties of prepared and live foods, salt mixtures of varying composition, and so on. The list is endless, but the resources of the hobbyist are not.

Therefore, the hobbyist must perform an exercise in prioritizing the factors that are truly critical to be addressed immediately, and those that should take second place. In a reef aquarium, as in many other complex systems, the Pareto principle can be applied.

The Pareto principle, or 80/20 rule, is a statistical principle that shows the unequal and unbalanced distribution between work and performance. It is applicable in business and economics, as well as in many other fields where an investment is necessary to obtain a result. In short, the rule emphasizes that 80% of the profit comes from 20% of the investments, or in other words, that, in a statistical environment, 80% of the results come from 20% of the causes. This statistical phenomenon implies a profit versus effort curve similar to the one shown in Figure 1.


Figure 1. In the aquarium, 20% of our efforts produce 80% of the results.

Therefore, a hobbyist should know that there is a limit to the reward for his effort, and it is never 100%. With each investment of time and money, results improve at a slower rate. Once the necessary time has been invested in adjusting the most impactful elements, the additional effort has a diminishing return, making any additional effort unappreciated. It is very important, therefore, to know how to identify which factors need to be addressed to obtain an 80% result and which are for subsequent "fine tuning".

Obviously, the amount of effort depends also on the knowledge and experience of the aquarist, but on average, it works this way. Every hobbyist has a different perception of what his or her satisfactory results would be, as they include a component of personal ambition, which is subjective and completely legitimate. However, for beginning hobbyists, it makes sense to set goals that are reasonable and relatively easy to achieve. The opposite is a source of frustration.

Let's look at an example. We know that the light radiation incident on the surface of the reef has mainly "two components": firstly, the light coming directly from the solar disk and secondly, the light resulting from all the reflections, diffractions and scatterings occurring in the atmosphere as a whole. This luminous environment can be reproduced in an aquarium by simultaneously using two light sources: on the one hand, a series of static fluorescent tubes and on the other hand, a mobile HQi spotlight that moves during daylight hours simulating the position of the sun. This method, which undoubtedly stands out for its exquisite elegance, makes little difference to the health and growth of fish, corals and invertebrates, involving a significant complexity that the average hobbyist does not need. In this sense we know that, for the conservation of fish, corals and invertebrates in captivity, it is not always strictly necessary to replicate 100% of the natural conditions, according to a reasonable criterion of complexity versus objective benefit.

And just as the actions of overprotective parents can harm their children, there are moments in the life of any hobbyist, in which there is a certain tendency to "over act" on the aquarium. From the best of intentions, there is an abuse in the administration of all kinds of additives, which according to their labels "help to...", performing countless tests at all hours, with constant changes of location of corals and invertebrates, and unnecessary consumption of live food. This "total control syndrome" leads the hobbyist to exhaustion, until his/her own reflection leads to finally conclude: "now that I don't pay attention to the tank, it looks better than ever". Once again, the well-known principle that governs our hobby prevails: "nothing good happens fast in a reef aquarium".

Therefore, we can establish minimum priority objectives that are the basis for further improvement through more complex adjustments. Some of these minimum objectives would be the following:
  • Healthy environment where all fish, corals and invertebrates, have all the right conditions to thrive
  • Well-fed fish, corals and invertebrates without symptoms of stress, infections, parasites, etc.
  • Aquarium free of unwanted algae pests
  • Robust biological stability


Figure 2. Some of the 20% factors for a reef aquarium

Some of the 20% factors that allow us to reach these objectives are the following:
  • Establish and consolidate a food web with a wide diversity of microorganisms.
  • Stable temperature and adequate lighting (PAR and spectrum)
  • Good water movement
  • Nitrate and phosphate balance sustained over time (months).
  • Marine water with major constituents in their recommended concentrations, with calcium, alkalinity, magnesium and potassium concentrations in their ranges, sustained over time (months).
  • Varied feeding for fish, corals and invertebrates.
  • Main parameters to monitor/maintain: ammonia, nitrite, nitrate, nitrate, phosphate, calcium, alkalinity, magnesium, potassium
During the first 12 months of the aquarium's life, as a reference, the goal is to achieve ecosystem stability. This implies an environment with a robust and mature food web, involving a high diversity of microorganisms, sustained nitrate-phosphate balance, and adequate nutrient flow. The hobbyist focuses on providing the conditions for this to occur: cycling with live rock, adequate lighting in spectrum and photoperiod, stable temperature, moderate addition of phytoplankton and zooplankton, adequate maintenance of calcium, alkalinity, magnesium, potassium and quality food for corals, fish and invertebrates.

Once sufficient time has been spent on the 20% factors, the aquarium will be in good biological health and robustness, so the hobbyist can begin to explore and invest more effort in the 80% factors, which provide further improvement by making more sophisticated adjustments. Some examples of 80% factors would be the individual maintenance of trace element concentrations such as, iodine, iron, manganese, cobalt, copper, aluminum, zinc, chromium, nickel or the fine tuning of strontium, potassium and pH.
About author
Angel Cegarra is the author of the book “Reefkeeping Fundamentals”, where he presents a fascinating journey through the science and technology that govern life inside a reef tank. From nutrient recycling processes, through coral biology, project initiation, feeding techniques and maintenance of water chemistry. The book includes world class reef aquariums description along with priceless advice on how they were planned and how they are kept healthy and vibrant. Covering the biology of coral reefs and relating it to the biological, chemical, and physical parameters considered when creating a reef aquarium. Home aquarist moving into an area of knowledge that was once the exclusive domains of scientists.

Link to Apple Books:

Link to Amazon (paperbak):

Latest reviews

Pros: Outstanding communication that the fundamentals of reef keeping are paramount to the success of our little ecosystems.
The article is a clear and concise accumulation of knowledge distilled to enforce the need for stability and maintenance of the basics to be a successful reef keeper. Love it!
Pros: A simple read and sense check, particularly for the mid level reefer (neither novice or expert) It is far too easy to worry about a single parameter that is misbehaving and the inevitable and often costly “panic” fixes.
Cons: Misses out some detail as to why the mentioned parameters and mechanical factors are important. Would be nice to have however based on the intent and style of the article doesn’t affect it greatly.
A really good read as a sense check for the new and mid level reefer (possibly as a reminder for the experienced reefer but would have to come back to you on that when I get there). Very easy to read. Clearly put forward by an author with a vast amount of detailed knowledge and experience who wants to help other reefers keep it fun.

recommend reading this!
Pros: To the point
Well illustrated
Very well done. Pareto principle for Reefers...Love it

Pros: Explaining The Pareto principle is a must read concept that is applicable to so many aspect of life and fits perfectly in reef keeping!
Cons: There isn't much in the way of explicit advice in the article
This article is clear, concise and directly discusses The Pareto principle as it applies to reef tank maintenance. It makes one think about the amount of effort we put into our tanks versus outcomes.

The valuable take home message here is about simplicity . A great, quick read!

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