Problem marine algae

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Problem marine algae

Hair alge

Ó The WaterZoo

A WaterZoo guide to…

Problem algae in the marine aquarium

There is no single factor that causes problem algae to affect an aquarium. What causes algae to grow in one aquarium, but not in another is not fully understood. Some aquariums are unaffected while others can be plagued by algae problems. Probably the single most important factor is water quality. Other important factors include accumulation of detritus, water movement & lighting. What we do know for sure is there is no quick & easy ‘one shot’ cure for removing algae.

There are three types of algae that affect marine aquariums.

Diatom algae

Is very fast growing brown film that grows on the glass especially in new aquariums with strong lighting. This will normally subside within a few months of setting up the aquarium.

Slime algae

Thick greasy algae that comes in Green, Red & Black varieties that covers rocks and the substrate, again very fast growing.

Hair algae

This hair like algae can choke sessile invertebrates, growing over rocks & substrate.

The first thing to realise is that all algae problems are caused by a variety of factors, not just one factor, e.g. lighting or phosphate. These are significant factors, but it is important to look at the bigger picture. Possible causes of algae include: -

Phosphate even relatively low levels of phosphate can cause serious algae problems, as well as inhibiting coral growth. Phosphate is what farmers put on their field to make crops grow faster, so imagine how well it promotes algae growth! Levels of Phosphate should be kept below 0.14 part per million. It does not seem possible to maintain this level with water changes alone, it will require some form of adsorbent media, we have found Rowaphos to be the most effective.

Nitrate will also encourage algae, although the levels have to be considerably higher to cause a problem. See The WaterZoo guide to nitrate for more information on ways to control nitrate.

Ammonia is unlikely in any aquarium with an efficient well-maintained filtration system and should not be a problem. There is evidence to suggest algae can take up Ammonia directly. It is also highly damaging to all fish & invertebrates. If you think your filtration is not quite up to the job check for Ammonia with a sensitive test kit 20 minutes after feeding.

Dissolved organics This is something overlooked by many hobbyists. The term covers a wide range of compounds for which test kits are not readily available. The easiest ways to test for dissolved organics is with a Salifert test kit. Again this should be kept at the lowest level possible.

Insufficient water movement / oxygenation Algae require carbon dioxide to grow, ensuring there is plenty of water movement and oxygen will make it more difficult for algae to grow.

Detritus build up Pockets of sediment are often the first place algae get foothold, plenty of water changes and siphoning help. A couple of powerheads just circulating water will help

reduce detritus build up as well as increasing oxygenation.

Old lighting As fluorescents & metal halides age they lose important parts of their spectrum this can encourage algae growth as well as having a detrimental effect on light loving invertebrates. We recommend replacing fluorescent tubes every 6 months and halide bulbs every 12 months.

Over dosing of supplements Some supplements are necessary for example Iodine as it is easily removed by protein skimmers. Lightly stocked aquariums with frequent water changes will not need the addition of lots of supplements. Only use supplements if you are sure that it will benefit your aquarium inhabitants. The most important supplements in a reef aquarium are Iodine, Calcium, Strontium & Molybdenum. Remember algae use trace elements too.

It is likely that a combination of the above factors is the cause of your algae problems.

How to reduce algae growth

Initially you should have a major clean up ensuring that all equipment is clean, and working efficiently. This should include a 20% water* change removing as much detritus & algae as possible & replacing soiled filter media. The role of a well maintained, adequately sized protein skimmer cannot be over emphasised, these remove large quantities of organic material as well as indirectly stopping the accumulation of nitrate & phosphate, these are three of the major causes of algae. Ensure there is plenty of water movement by adding additional pumps if necessary. These help to prevent dead spots where detritus accumulates. Replace any bulbs over six months old as the spectrum emitted deteriorates over time, this helps promote algae growth. There are several products that can help improve water quality quickly these are: -

Polyfilter, these remove large quantities of dissolved organics as well as some phosphate & nitrate.

Rowaphos is an excellent product for removing phosphate, although several applications may be needed to reduce high phosphate levels initially. This product also reduces silicate a more minor algae causing factor.

Kent PolyOx is a powerful oxidizing agent that can speed up the cleaning process that is especially useful if you have a problem with slime algae.

The large-scale use of algae eating inhabitants is not the answer; these animals will not be able to deal with a massive outbreak caused by poor maintenance and high phosphate. Although they are a useful tool in reducing algae, we would recommend at least one Red leg hermit & one Turbo snail per five gallons of aquarium water.

Over the following six weeks you should change a minimum of 15% of the water* every week, again siphoning out as much detritus & algae as possible. Clean mechanical filter media as soon as it becomes soiled. Change the Polyfilter as soon as it becomes discoloured. Ensure the skimmer is clean, pay close attention to the neck of the skimmer as a build up of ‘gunge’ drastically impairs its ability to function correctly. Also, closely monitor your feeding regime & reduce the quantity where possible. Less food going in to the aquarium means less work for the filtration system, this will slow the accumulation of undesirable matter.

At the end of this six week period your water should have an improved quality / clarity, the

inhabitants will look much healthier and the algae should be starting to retreat. However, it is still important that your carry out frequent partial water changes & maintenance to prevent the algae from returning.

* Where at all possible water changes should be carried out with reverse osmosis water at the same temperature and salinity as your aquarium. Topping up due to evaporation should also be done with reverse osmosis water. R.O. water is almost pure water with approximately 95% of all contaminants removed.

Further reading.

Algae: A problem solver guide by J. Sprung

The Marine aquarium reference book by M. Moe Junior.

Interpet Question & Answers of the marine aquarium.

The WaterZoo 439 Lincoln Road Millfield Peterborough PE1 2PE

Tel. 01733 312142 www.waterzoo.co.uk