Dont be caught out…Something bad can happen to your overall saltwater quality as your tank ages! But if you have a fish-only tank dont worry; this only really applies to systems that contain live rock and/or corals.

Old tank syndrome can affect any reef tank!

Old tank syndrome can affect any reef tank!

As we all know a good understanding of saltwater chemistry is crucial to your success keeping a marine system stocked with life that demand certain chemical parameters (especially corals). Usually this is as easy as keeping a regular eye on things like pH, nitrates, phosphates, temperature, salinity and calcium (for systems containing live rock and/or corals) using test kits and measuring devices and adjusting these parameters as necessary.

What’s happens to your coral life support system as your tank ages?

Over time your established marine aquarium water quality can and does deteriorate, this is especially true if you keep corals. It is a common belief that over a few years of successful coral keeping growth rates will dwindle and the corals will stop growing. Many aquarists experience this and this occurrence has been dubbed “old tank syndrome”…

What is old tank syndrome?

For a start lets define “new tank syndrome” which is the incapacity of newly established bacterial colonies in the biological filter to cope with the output of organic waste leading to system crash as toxic metabolites build up. This happens in newly established tanks especially when marine life is added before they have been completely cycled.

1.4Old tank syndrome in a nutshell is slowly declining water quality over time (years usually) leading to less than ideal conditions for marine life survival. This decline is not as obvious as one might think and pretty much results from many things being added to the water and not ever being removed completely (water changes are the ONLY way anything can be gradually diluted out of your system).

Time is the crucial factor with old tank syndrome as parameters are gradually decreasing so slightly we cant detect them week to week and we aren’t really paying attention to the bigger picture anymore, parameters are starting to drift very gradually; we are lead to believe that everything is stable and predictable and become complacent…until suddenly we realise the tank is failing to thrive as it once had and we witness gradual decline of marine life such as the cessation of growth of corals and/or mortality of newly introduced fish or invertebrates as they are chemically shocked by the water conditions their other tank mates have been able to adapt to over time (there may be some fatalities over this time that the owner puts down to natural causes, but in reality these deaths may have been from less than ideal water parameters).

What are the causes of old tank syndrome and how can we remedy them?

1. Basically the main cause is neglect, as I said we become complacent, what we are doing is working so we get a bit lazy checking our parameters (water testing) less regularly and start doing water changes less often, basically we begin to take our tanks for granted! The key to long-term success is a diligent maintenance routine and care over the years.

Other causes for old tank syndrome are:

  1. Decreasing alkalinity over time, which gradually makes the water more acidic. Test your alkalinity!
  2. Increasing nutrients, that never get completely removed from the system. Correct regular partial water changes can remedy this.
  3. Inhibition of light and water movement from coral growth. Upgrade your systems components if you need to as your corals get massive.
  4. Competition between corals resulting in chemical warfare (alleopathy), activated carbon can remedy this.
  5. Infrequent water changes. Water changes dilute nutrients in your system this is the only way to completely get rid of them.
  6. Feeding your marine life incorrectly. Feeding should be done frequently in small amounts.

This blog post should arm you with enough information to prevent old tank syndrome occurring in your system.

Saltwater Aquarium Advice