Dear hobby:
Yes, it is not unusual for a microalgae to begin appearing in a new aquarium as it cycles. This usually occurs when the nitrites are cycling and nitrates are beginning to build up in the aquarium. The nitrates are like a nitrogen-based fertilizer for your garden, and high levels of nitrate will fuel the growth of algae.
If the algae is green, this is often a welcome sign in a new aquarium — an indication that nitrites are beginning to accumulate and that the cycling process will be complete before too much longer. So if the algae is a green film that builds up on the aquarium glass or substrate where the light is brightest, that’s nothing to be concerned about. Feel free to clean it away from the viewing surfaces on the aquarium, and if you find it unsightly on your aquarium decor, just leave the aquarium light off while the aquarium cycles and that will control the growth of green algae.
However, other types of algae growth are undesirable, and you will want to remove them or control them as soon as possible. Nuisance algae includes yellow and brown algae (most often due to diatoms), red slime algae (cyanobacteria), and the dreaded hair algae. Hair algae ranges from very dark green to almost black in coloration and is fuzzy in appearance rather than appearing as a film.
If the algae you noticed is yellow or brown then it is most likely due to a bloom of diatoms. They are harmless and most newly set up marine aquariums go through a stage where the diatoms or brown algae grows on surfaces in the aquarium. In most cases, the brown algae will disappear as suddenly as it appeared once it uses up the available supply of some key nutrient in the aquarium (usually silicates). Ordinarily, once the available silica has been exhausted, the population of the diatoms will crash and they will then typically die off on their own. So right now, while your tank is still cycling, you needn’t be concerned if your tank is experiencing a bloom of diatoms — in all probability, that problem will soon solve itself.
Brown diatom algae is usually the first problem algae that a new marine aquarist encounters. A bloom of brown algae often occurs soon after one introduces new live rock to a marine aquarium. This bloom occurs because the curing of the live rock introduces of silicates and nutrients (even pre-cured live rock from your LFS will have some die off after it is transferred to a new aquarium; that’s normal). As a result of the diatom bloom, a brown film soon coats everything inside the tank. Control of brown diatom algae is relatively easy. The first thing to do is to purchase Trochus or Astraea snails that eagerly consume the brown diatom film. I’ve had good results purchasing Trochus snails from IndoPacific Sea Farms (IPSF). There are other snails that will clean the glass such as Nerite and Strombus snails, but Trochus and Astraea snails are the brown diatom cleaner workhorses. If you have your cleanup crew in place, hobby, and it includes Astraea and trocha snails, that will help to get brown algae under control.
Some aquarium scavengers and sanitation engineers are also especially good at eating slime algae or hair algae, so let me know if the algae appears like red slime (cyanobacteria) or fuzzy dark green-to-black hair algae and I can help you to eliminate the undesirable algae.
It’s a good thing that you discovered the salinity on your aquarium was running so high. Gradually reducing the salinity to between 1.024-1.025 may also help control the algae by altering the conditions that it apparently finds favorable for growth. When the time comes, your first seahorses will do best at a salinity of 1.024-1.025.
However, if you already have your cleanup crew in place in your aquarium, be especially careful to lower the salinity very slowly, since many snails cannot tolerate rapid changes in salinity.
Best of luck completing the cycling process for your new aquarium, hobby! Regardless of what type of algae you may have, leaving your aquarium light off while the tank cycles will help to eliminate the algae and dramatically slow its growth.
Respectfully,
Pete Giwojna
Ocean Rider, Inc. is an Organic Hawaiian-Based Seahorse Aqua-Farm & Aquarium that Follows Strict Good Farming Practices in Raising Seahorses and Other Aquatic Life.
