Does Natural Algae Control Actually Work

At some stage in practically every aquariums life it will become the end result of an algae outbreak. Quite often these outbreaks simply disappear on their own, however on some occasions they simply will not go away and no matter what the aquarist does they simply return.

It is important to understand in the first instance why algae takes hold and grows in the aquarium.

All algae require an energy source. This energy source could be a particular colour temperature in the light, a nutrient in the water etc.

Therefore the algae outbreak could be due to the lighting not being replaced and the incorrect colour spectrum being transmitted into the aquarium. Some algae like this particular temperature and then grow. The light to the human eye will probably look fine however unless you perform a specialist test you will not know. The best thing to do is ensure that you change the bulbs at the correct time period based upon manufacturer’s recommendations.

The second and probably the most common one is where algae feed upon nutrients in the water. The most common nutrients and nitrate, phosphate and silicates. In this scenario especially for nitrate and phosphate it can be hard to locate. The reason for this is that the algae are taking up the nutrients from the water column and therefore when a test is performed the parameters appear to be ok. As soon as the algae is removed from the aquarium the levels start to increase and the algae takes hold again.

It is a vicious circle unfortunately.

As the saying goes though – prevention is better than cure.

The best prevention is to ensure that the equipment in the aquarium is correctly maintained and replaced if/when required as well as the water parameters being kept at the highest possible standard.

A very useful part of obtaining these parameters is the reduction/removal of nutrients. An excellent way to reduce and/or remove nitrate and phosphates is through the use of natural based control.

This natural based control could be live rock, deep sand beds, mud beds, refugiums, mangroves etc.

Live rock for example is exceptionally powerful at filtering the aquarium and if enough high grade quality is purchased then it can also assist in the reduction/process of nitrates.

It is my opinion that there are two natural based packages which can be used for both filtration and nutrient export.

These are:

  1. Live rock combined with a deep sand bed – This allows for efficient filtration of the aquarium via the live rock and also for nutrient export via the deep sand bed.
  2. Live rock combined with a refugium – This again allows for the efficient filtration of the aquarium via the live rock and also for nutrient export via the refugium where macro algae is grown.

In the refugium example above I personally find it interesting that you can use algae to control algae. The reason this can be performed is that the algae which you are growing in a separate aquarium can be harvested from time to time. The algae removes nutrients from the water and uses this for growth. When the algae is harvested from the aquarium the nutrients are removed as well. As you are not removing all of the algae then the remaining algae feeds upon the nutrients in the water and maintains these parameters at a low level. Because the algae is located in a separate aquarium no or minimal algae outbreaks should occur in the main display aquarium. This is not to say you will never receive any because you might however it severely reduces the possibility.

These are not the only methods which you can use as there are many more. Mangroves for example are very powerful but they are very slow growing and therefore reduce the nutrients at a slower speed.

The aquarist, however should never rely upon these techniques and needs to ensure that the correct care and maintenance is still employed, the fish are not overfed etc.

Simply put in response to the question in the title of this post – yes natural algae filtration does work as long as it is properly implemented and cared for.

Follow nature and keep it simple.

  1. This is a great post, but I could really use a more in depth understanding. I’ve just started my first tank ever, and I’ve gone with a smaller (24gallon) unit. I’m scared that the thing is going to be more maintenance than I’m willing to chip in.

    I don’t have any livestock in it yet. Just the water and a live rock. I’ve been told to let the system get ‘stable’ for the next two weeks. My first challenge is temperature. I’ve noticed the tank is always hotter than than room temp. I live in Texas, and we have warm weather almost year round. Here in early october the high is 76F. today, with the lights on, my tank was running 85.4F.

    The shop that sold me the tank said that anything above 80F will stress the fish out. Now, if i understand you correctly, i’m going to need to worry about algae too. OH NO!!!!

    I could turn the A/C on, but i would really like to avoid that. I could also purchase a chiller, but i would rather turn the tank off and box it back up. I refuse to pay that kind of cash for equipment, that also has a huge energy cost associated with it.

    Could you comment on temp ranges for most fish, and what temp ranges work best to avoid algae?

  2. Ihave a 33 gallon salt tank , a friend gave it to me with an algae problem.She’s been dealing with algae for a year and now i have it.It’s my first salt tank and i just can’t get ride of the algae.My tanks at the perfect temp, I’ve been trying to get the phosferate levels down but i just can’t keep up with it no matter how many times i chang the water in a weeks period.Know i have this black bubbly stuff growing on my live rock. What am i missing?

  3. Hi.

    First thing, don’t fret!

    The general temperature range for a marine aquarium that is usually given is 75 deg F to 84 deg F. It is best to run the aquarium cooler than the highest stated – I run mine at 77 deg F with a +/- 1 deg F variation.

    It is important to have stability. Therefore it follows that a temperature should be selected that is within the range given, preferably not above 80 deg F, and can be maintained without excessive ups and downs.

    Hopefully there will not be a need to purchase a chiller. In the summer when the air temperature affects my aquarium I run a fan. These are quite cheap to buy and cheap to run. The air flow can be directed across the top surface of the seawater which dissipates heat and also gets rid of lighting heat. I’m fortunate in that I simply blow air across the front of my aquarium and this is enough – the air flow makes the aquarium act like a radiator and thus lose heat.

    Many new aquariums go through an initial ‘algae cycle’. This algae is often a gold brown colour and the algae utilises silicates. When the silcates are gone, the algae goes. A problem with algae does not need to occur. It is down mainly to seawater quality. I assume you have basic test kits such as ammonia, nitrite, pH, and nitrate. A worthwhile additional one is phosphate. Nitrate and phosphate are nuisance algae nuitrients, and preferably should read for nitrate 10ppm or less, or as low as possible, and phosphate 0.01ppm, or preferably zero.

    Phosphate gets into the seawater through feeding, so it is very important not to overfeed livestock. Nitrate likewise, but it also appears because of livestock and is the result of the Nitrogen Cycle (the biological filtration process required in all aquariums). Live rock in high enough quality and quantity can deal within reason with nitrate. The main way of controlling it is by carrying out routine seawater changes, the guideline is 10% of the aquarium net gallonage per week.

    There is a great deal on this website about such matters as mentioned above, see ‘Articles’ and also ‘Blogs’. You can also click on different categories by going to the Home Page and putting the mouse pointer over different headings.

    One point if I may. You mention “a live rock”. Live rock is an excellent biological filtration media. However, there must be enough of it. This is an absolute. Before adding livestock at all (and adding livestock must be done slowly over a period) speak with your supplier about the necessary quantity of live rock you require.

  4. Hi Autumn.

    Sorry to hear about the algae problem.

    If you have a constantly high phosphate level it could be reduced by using anti-phosphate media. This is easily available and needs to be contained in a suitable device, such as a small canister filter etc. The media has a limit to its capability so should be changed as necessary.

    As you are doing seawater changes (as should be done) there is a need to look for the cause of the high phosphates. Phosphates are mainly introduced into the aquarium with food for the livestock. A high number of aquarists overfeed as they assume the livestock need more than they actually do. So I suggest you examine this aspect.

    Also, to an extent, algae can create algae. When algae dies, all that it is and contains is released back into the seawater, so further nutrients are provided. If you are ‘killing’ algae ensure that it is removed as far as possible.

    In addition, once a nitrate/phosphate problem has been solved it can be a while before they disappear completely, but the levels will fall away.

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