How Macroalgae Benefits Coral

Many hobbyists are constantly looking for ways to increase the health and vitality of their corals. There are many obvious ways to achieve better coloration and more prominent polyp extension, such as proper lighting, flow, and water chemistry. Macroalgae can solve many issues. It is widely used in the hobby, but only some know its specific advantages to corals. In this article, we will discuss how macroalgae can benefit corals!

Stabilizing pH

In a reef aquarium, the pH is naturally higher during the day and lower at night. This phenomenon occurs because corals and algae consume CO2 for photosynthesis, leading to less CO2 and higher pH when the lights are on. At night, the fish generate CO2, but the corals and algae aren’t consuming it because they are not photosynthesizing. The corals are breathing as well, contributing to more CO2.

Why does this matter? Corals require elevated levels of pH to grow. When the water is too acidic (low pH), the corals won’t grow. Your corals will still grow if the pH is depressed at night as long as it isn’t too low. However, having fewer pH fluctuations between night and day will make your corals less stressed and happier. Don’t get the wrong idea about this, though. Having lower pH at night won’t dramatically stress out your corals in most cases. It is competently acceptable to have lower pH at night. Although, if you are trying to make your corals as happy as possible, more stability is better.

How does macroalgae help you get more stability with your pH? As we established, the pH is naturally lower because corals aren’t consuming CO2 at night. If you have a refugium in your sump or as a separate tank, you can limit the amount of CO2 at night using macroalgae. If you run your refugium light opposite your display light (reverse photoperiod), the macroalgae will consume CO2 at night while the corals aren’t photosynthesizing. This will lead to more stable levels of pH between the night and day. You don’t have to run a reverse photoperiod for your refugium if you don’t want to, but you can if you want to increase the pH levels at night.

Macroalgae can also increase your pH levels overall. Macroalgae is an excellent way to boost your pH if you want to use something other than kalkwasser. If this sounds like what you want, running a more extended photoperiod might make sense. Some hobbyists have their refugium light on for 24 hours every day.

Lowering nutrient levels

Most hobbyists want macroalgae to lower their nutrient levels. Macroalgae works the same way microalgae (nuisance algae) does, but it is more manageable. It won’t smother your corals the way hair algae will. You can also keep it maintained in a separate area like a refugium. However, it will consume nutrients the same way microalgae does. We could spend another article discussing nutrients, but most hobbyists understand why high nutrients are harmful.

High nutrients can slow coral growth and even cause them to die. Much before that happens, you will likely see explosive algae growth. The microalgae can cover and smoother your corals. Macroalgae prevent this by directly competing with the microalgae for resources. Also, by growing your macroalgae in a refugium, you can provide it with more ideal lighting conditions, giving it an advantage over the algae growing in your display.

Less algal growth in your display tank benefits your corals for apparent reasons. If you have an algae problem, adding a refugium with macroalgae to your tank can slow the growth. Then, when you remove the nuisance algae, the macroalgae can prevent further growth.

Macroalgae helps to remove silicates and toxins

Macroalgae remove more than just nitrates and phosphates. It can remove silicates and metals as well. Silicates are typically an issue for those with a newly set up tank or those with poor RO water. Silicates can contribute to algae growth similarly to nitrates and phosphate. Therefore, you should try to limit silicates in the water. The primary way to do this is with a RODI unit. However, silicates can still enter anyway, which is why macroalgae are helpful.

Other toxins can get into the water, such as copper. Having heavy metals is rarely a significant issue for most aquariums. However, they can cause lots of problems if they become too concentrated. The first thing you will see with lots of heavy metals is algae growth. If the heavy metals become overly concentrated, your corals may bleach, but this is rarely an issue. Macroalgae can consume contaminants such as iron and copper.

Less heavy metals in your water will significantly benefit your corals by reducing microalgae growth and making the water cleaner overall. Adding macroalgae can reduce or eliminate heavy metals and silicates in your water.

Copepods love macroalgae

We discussed the main benefits macroalgae provides for corals, though there is another indirect benefit. Macroalgae is an excellent habitat for copepods and other microcrustaceans such as amphipods. Copepods offer several benefits to your corals. First, they help maintain nuisance algae. They can also assist with a diatom outbreak. Second, they will eat detritus in the aquarium, which results in less detritus that can rest on your corals. Lastly and most importantly, copepods are an excellent food source for corals. As the copepods dart around in the water column or on the rocks, they will make their way near corals, allowing the corals to capture and eat them.

Of course, you can keep copepods without macroalgae, but macroalgae is an excellent place for them to breed.

You can use macroalgae for many different things, including improving the health of your corals. Keeping macroalgae in a refugium can remove nutrients, silicates, and even heavy metals from the water. This will help with overall water cleanliness and limit algae growth. Macroalgae also help stabilize pH at night if used on a reverse photoperiod. If you want, you can use it to raise the pH level overall. Finally, macroalga is an excellent habitat for copepods, which are a perfect food course for corals. If you want some macroalgae for your aquarium, look no further than AlgaeBarn for all your refugium needs!