Algae- How To Deal With It
Everyone gets algae eventually. Most people react negatively when they see it- but is it really a problem? And if it is, what can we do about it?
TL;DR at the bottom!
First we have to understand what algae is. Algae is a broad term that refers to many different eukaryotic organisms ranging from tiny unicellular diatoms to multicellular seaweed! However, when most people say algae they think of the green film or green water you see in aquariums. These are almost unanimously considered unsightly and can be difficult to get rid of once they have started to appear.
So what kinds of algae do we see in aquariums? Many different kinds, with different causes and methods of management.
First, lets talk about whether or not you need to remove it.
Should you get rid of algae?
Most people would jump to answer this with “Of course!” However, algae is not inherently a problem for aquariums. In fact, it can also have benefits! It provides essential food for many species of fish, shrimp, and snails. It can also help keep your water clean by absorbing fish waste, which it uses as nutrients (just like plants!).
In fact, in saltwater aquariums macro algae is often used as a natural biological filtration method.
So when IS it a problem? If it is clogging equipment such as filter intakes, tubing, or clogging up your filter media it needs to be removed. It can also grow over and choke out live plants, depending on the algae!
It will not harm your fish, however.
So how does one get rid of it?
You’re not going to like the answer to this... Honestly, most people should only expect to manage algae, not completely get rid of it. You’ll set yourself up for a lot of frustration if you try to ERADICATE your algae. It’s very, very difficult or even impossible to completely get rid of algae, and even if you DO, it could just come back later. So how do you remove it in the first place? The answer is two fold.
You need to remove the cause of the algae to prevent it from coming back. This is really important!
If you remove the algae but don’t change anything else, you’re just going to have more in a few weeks!
So what causes algae?
Algae shows up in large or problematic amounts because of an imbalance in the tank. It thrives on light and fish waste. If you have algae, you have too much light or too much fish waste. The number one problem I see causing algae are high nitrates- caused by a lack of water changes. This is VERY easy to fix! Simply test your water (test for ammonia, nitrite, and nitrate) and do water changes as needed to bring your nitrates down to 20ppm or below. This may mean doing a 10% water change DAILY for over a week! But once it’s down you should be able to keep it there with regular (weekly) water changes. If it spikes back up... your tank is overstocked! Ya gotta upgrade, sorry.
The other player in this is light. It’s very, very common for people to leave their tank light on 24/7. Please don’t do this! Not only will it cause algae (most often green water) but it’s bad for your fish. They need a day and night cycle just like we do. Limit light to 6-8 hours a day, TOPS. This goes for planted and reef tanks as well! Another huge factor is if the tank gets hit by light from a window. This is a BIG no-no! Any time light does this it is way too powerful for the tank, thus growing algae.
A less common cause (or at least a factor that could encourage algae) are phosphates. Phosphates are essential for live plants, but too much grows algae too. It can be found in tap water, or it can be released into a tank from carbon (yes, the carbon in your filter pad!). Most planted aquariums do better without the use of carbon in the tank, and some even go so far as to use RODI water that they remineralize to prevent algae growth.
So now that we’ve done that, what is the other part to removing algae? Well... it’s removing it! By hand!
If it’s simple algae growing on the glass it can be removed with an algae scraper during your weekly water maintenance. Same goes for algae clogging intakes etc.
If it’s on live plants, you have to try something different. Take out any decor or plants that are affected and spray them with hydrogen peroxide. This will not harm the plants and after a quick rinse or dip in dechlorinated water, it’s safe to add back to the tank. Repeat this several times to get rid of most of the algae. This works well is black beard or hair algae.
Another method to remove algae on plants (or in general) is to start using Seachem Excel and Seachem Flourish. Excel is known to help get rid of algae, and by properly fertilizing your tank your plants can out compete the algae for nutrients! Take care not to overdose fertilizer or excel, however, as this will only make algae worse!
In saltwater tanks, if you’re dealing with cyanobacteria (a red, slimy “algae”) you may be able to manage it by doing the above water changes/light reduction in addition to adjusting your water flow. Cyano likes low flow areas (like the bottom of the tank) so by stirring up your sand and adding a small powerhead along the bottom of the tank, it will help reduce build up.
What about algae eaters?
A very common solution most people come up with for algae in their aquarium is to buy an “algae eater”. Whether this be a pleco, a snail, a tang, or a blenny people think that the addition of this animal will clean up their problem.
This is wrong.
The problem with doing this is explain in part above. High nitrates (from lack of water changes or overstocking) is the number one cause of algae! So by adding ANOTHER fish into your tank (that is already dirty or overstocked) you’re only going to make things worse!
And even if the tank is stocked correctly and the algae is only mild, there is no guarantee that your algae eater will even eat it! The name “algae eater” is misleading. Many fish with this moniker are actually omnivorous, not herbivorous! Meaning they will gladly or preferably eat things OTHER than algae. And even some of the best actual herbivorous “algae eating” fish don’t eat ALL types of algae! So depending on what is in your tank, they may not even be able to eat it!
So in the end, if you see a little algae, don’t sweat it! If it starts to cause a problem, deal with it and move on. Every tank has algae, it’s ok! Even those really pretty ones you see on instagram or youtube. I promise you!
TL;DR
Your tank is either getting too much light (reduce to 6-8 hours daily) or has high nitrates (test your water to check). Do water changes till it’s clean and keep cleaning it regularly. If it’s still dirty your tank is overstocked. You DO NOT have to add an algae eater! (that may in fact make it worse)
