What kind of algae is this and how do i get rid of it?

[Damiri]

So our tank started developing this grey fuzz on everything. Looks ugly and i am sure is not good for the fish. Does someone know what it is and how to get rid of it?

 

[Baker]

It's black brush algae, aka black beard algae. Totally fish safe, but can be bad for plants if it gets out of control. Fish such as mollies and Florida flag fish eat it, typical clean up crew fish and inverts eat it, or you can clean it off of plants with hydrogen peroxide. But the root of the algae growth is an imbalance in the ratio between light/ferts/co2

 

[Byron]

That is brush algae, some call it beard algae. It has a couple of different forms, and I have had both. There is no danger to fish, but if it becomes out of control it can kill plants by suffocating the leaves. However, I have found that in some of my tanks it will rapidly spread on a dead leaf but not healthy leaves, so don't jump to conclusions. I have it on bits of wood and branches in some tanks and it is very "natural," just so long as it is under control.

In planted tanks, problem algae is due to an imbalance of the light/nutrients. We can take a look at this if you post your tank data: tank size (volume and dimensions), light specs (type, watts, spectrum, duration, etc), plant species (a photo of the entire tank will answer this easiest). And what if any fertilizers you use. And water change data.

Byron.

 

[Damiri]

We have a 120 gal tank (6X2X2), with CO2 supplementation although i am not sure at what rate. We are not using any fertilizer but we have had issue with lights. The one led strip that came with the tank was not enough for a planted tank so we tried and returned a bunch of other lights and finally settled on Odyssea lights last week. We use two sets of the 36" lamps which have 4 bulbs each of the 6500K 39W.

The Led lights were on 6am to 10pm with blue light 10pm till midnight. The Odyssea lights are on on the same schedule for two sets of bulbs with all four sets on between 10am and 5pm.

the algae are growing on pretty much anything in the tank.

Odyssea T5 Quad Timer 6500K Aquarium Light HO Freshwater Plant Discus (36")

 

[Baker]

figuring out the right ratio of light/ferts/co2 is quite simple. Trial and error, just start tweaking the variables one at a time and eventually you will come to a state of equilibrium and you might make some discoveries of your own along the way.
Giving us your specs and asking us to fix it for you isn't going to help long term because the second you change that enviornment around even slightly, your ratios are going to need to be adapted again.
For example, we can tell you to run "x" light for 10 hours, dose this much fertilizer twice a week and set your co2 diffuser to "y" but as your plants grow or you add new fish, etc. you're going to find that the tank as an ecosystem is going to diverge from the routine schedule that we recommend for you.
You just need to start experimenting with one thing at a time and see how your tweak begins to effect the system over time. Personally I think you're running an excess in light and at a certain point your plants make no use of it and this opens an opportunity for algae to uptake the excess light and outcompete the plants. If you don't already have a timer I say pick up a cheap one and set you lights to come on for about 10-12 hours instead of the 14 you currently run them. See how this change effects the tank over the course of a month or so and then move onto another variable.

 

[Byron]

I'm going to be general in my comments, as I do not know these lights. But three things stand out. But I'll begin with background.

Plants need light of a certain intensity to drive photosynthesis (this varies from species to species) and it must also have red and blue as these drive photosynthesis (red is the more important for this). Along with the light, nutrients have to be available; here too plants have varying requirements, and nutrients must be in a basic proportion. This light/nutrient issue is the balance I mentioned previously (Baker did the same). If the balance exists, plants will use the light and nutrients better, but as soon as this balance is out, plant photosynthesis can slow, even stop, and algae takes advantage because it is not anywhere as fussy about this balance. Which is why you will see some type of algae in any fish tank, whatever the light. It just has an easy time.

Photosynthesis depends upon the light intensity, but also is limited by any nutrient deficiency. Liebig's Law of Minimum is the technical term; Liebig discovered that plant growth is not dependent upon an excess of any nutrient, but solely on the limiting nutrient that is insufficient.

To the issues I see. First, blue lights promote algae because the plants cannot use just blue light for photosynthesis so the blue light is available for algae. This is advantageous in marine tanks, but not freshwater planted tanks. Used as "moonlight" very minimally, this shouldn't be problematic for algae, but here it is just one more factor that adds to the algae issue.

Second, there is most likely a deficiency in nutrients. You have what I will surmise is probably decent to bright lighting, but with out sufficient nutrients the plants cannot make use of it, so algae does.

This brings me to the third thing, CO2. This is a macronutrient for plants, but in excess (beyond the plants' needs, combined with the light and other 16 nutrients) it will promote algae. Any nutrient, but especially the macros, will do this if things are not balanced. This is part of why algae becomes problematic in light that is not sufficient intensity/spectrum for photosynthesis; the nutrients cannot feed the plants so algae uses them.

You need to be adding a nutrient supplement, but not knowing much about the light I don't want to suggest specifics on the nutrients. But I'd bet they are lacking here. I would also suggest floating plants; these can really help with light-related aspects, but they are fast growing which means more nutrients. I see Anubias in the photo, this is a low light low nutrient plant, and frequent develops brush algae solely from too much light; the floaters should handle this.

Edit. A comment about my own experience with this algae. It has increased due to too long a duration for the tank light (exceeding the balance with available nutrients) so cutting back the duration solved that. I also had it increase in summer, and discovered this was due to the increase in intensity and duration of daylight entering the fish room; heavy drapes in summer solved this. I have also had it increase by using too much fertilizer, and cutting this back depleted the algae, twice. My point is, that the balance is the key.

Byron.

 

[Damiri]

Thank you very much. This was a lot of interesting information. I had no idea that so many variables were involved! I guess i can start by getting some floating plants and cutting down on how long the lights stay on and see how it will affect the environment. I never thought of using a fertilizer which is funny since i am a gardener and i use one on my garden plants so why was i thinking the aquatic plants dont need one? The good news is the algae is not dangerous for my fish which i was afraid i was.

 

[Byron]

Thank you very much. This was a lot of interesting information. I had no idea that so many variables were involved! I guess i can start by getting some floating plants and cutting down on how long the lights stay on and see how it will affect the environment. I never thought of using a fertilizer which is funny since i am a gardener and i use one on my garden plants so why was i thinking the aquatic plants dont need one? The good news is the algae is not dangerous for my fish which i was afraid i was.

A follow-up on fertilizers. Nutrients for plants occur naturally from fish food and water changes. Primarily fish food, so the more fish, the larger the fish, or the more they are fed, the more natural nutrients will occur. Not suggesting you go down this road, this can be risky too, for fish as well as causing algae. But it is possible to have sufficient nutrients naturally, depending upon the fish, and the plant species and numbers, and the light intensity. However, in your situation, there is not much doubt that nutrients are likely insufficient. The light looks good, though again I don't know anything about this brand, so reducing the duration and adding fertilizers may help. A comprehensive liquid like Seachem's Flourish Comprehensive Supplement for the Planted Aquarium or Brightwell Aquatics' FlorinMulti are two I would recommend. Whichever, look for these exact names, as the manufacturers make several products in the lines.