Opposite to the beauty of wanted macroalgae in the marine tank, unwanted microalgae - so-called nuisance algae- can become a nightmare for aquarists.
To identify them is a task which is with some research normally done quite quickly, but to get rid of them can take weeks if not months.
From our experience, we want to give you one possible guideline to get rid of these unwanted pest algae in your marine aquarium, to bring back
the enjoyment of this fantastic hobby.
We know that there are very different approaches, so feel free to add your comments and ideas below. This guide will concentrate on the general approach to this problem and is therefore much shorter and more focussed written.
Please have a look in our Introduction and future articles when you like to dig deeper into this topic.
Nuisance Algae - Why do they grow in your tank?
The basis for the growth of algae in your tank is the existence of Phosphate and Nitrate in the water ( we neglect other chemicals algae might need as trace parts, to keep it simple here),
plus a sufficient lighting.
The main reason how phosphate gets into the marine tank is with the food, especially by frozen food and some phosphate rich flake food products.
In short words... comes mainly from the excretions of your livestock and decomposing material.
The usage of dry or older "liverock" can cause your tank to cycle again, and will normally cause an algae bloom, which takes normally a few weeks.
Even larger movements of existing liverock in your tank can cause a new algae bloom.
How to get rid of nuisance micro algae?
1) We recommend to rinse frozen food in a sieve with marine water, to wash out as much of the
phosphate as possible, before giving it to your fishes.
2) Check the food flakes you are feeding regards the phosphate percentage, and choose a product
your fishes still like with a lower phosphate percentage. We find the flakes from Ocean Nutrition
3) Don't overfeed!
4) Do regular water changes with a quality salt mix, with zero TDS RO/DI water.
Whilst the Nitrate and Phosphate levels are high do even much more often water changes.
5) Use an appropriate skimmer for your tank volume and increase the output, which means wetter
skimming. Don't wait for a week or even longer to get it full. As more as it gets already out of
the water, as less it can build up!
6) Think about the usage of PO4/NO3 binding media. But don't overdose. Don't rush this part, as it
can cause dangerous problems to your livestock if done too fast.
7) Check the water flow in your tank, and try to avoid areas of your live rock, without a good flow
(so called dead zones) , as this can cause the buildup of detritus.
If this is not possible give those areas a good blast with a turkey baster or a low volume
powerhead regularly. If not already using a filter sock think about to use one in the future.
8) Depending on your livestock reduce or turn off the light for a few days. This is not a problem for
fishes, but some corals and macroalgae might suffer.
9) If possible reduce or turn off for some further days the white, green and red colours of your
9) Check that the tank is not getting direct sunlight.
10) Manually remove as much of the nuisance algae as possible, for example with a brush etc.
11 ) Turn the rock with the unwanted algae upside down, so it doesn't get any light at all. Or place
another rock on it, to keep any light away from it.
Do you have any question we can help you with?
As an aquatic algae farm, we don't have a public shop to visit unfortunately but we are happy to post all our macro algae species within the UK for free to you.
And we are sure you will like your new macro algae addition once received.
You can register your interest on the algae page you are looking for to get an email once it is back in stock or stay informed via our Newsletter, and or to follow us on Facebook, as we will first inform there when our algae are ready to sell again, or when we received new
When a macro algae species sells well we have sometimes to take it out of the sale as it will need time to regrow again.
The time for this will vary, as some macro algae species will grow very slow, whilst other - especially various Caulerpa marine macro algae species grow quite fast.