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Your tank suddenly looks like a science experiment on green things, and you're not crazy. Almost every fish tank goes through an algae bloom once the aquarium is mature, or maybe the lights are working a bit too hard.

The thing is, it doesn't exactly "mean your tank is dirty." It just means your ecosystem is out of sync by a little bit. And thankfully, you don't have to rip your whole tank apart to get rid of it.

Here's a real-world guide on how to get it cleaned up and, more importantly, how to prevent it from coming back.

Why Does Algae Happen & Why Does It Seem to Pop up Overnight

Usually, the first sign that algae is becoming an issue is on the glass. It will start as a faint green tint, and then all of a sudden, just a few days after you cleaned it, there's more algae there.

The reason algae grow is generally an imbalance of light + nutrients + time.

The moment you leave your light on for too long or give it too much light from a window, and combine that with leftover food and waste settling into your gravel, you have the perfect condition for algae to thrive.

I've even seen aquariums that look picture-perfect on the surface -clear water, active fish- but the glass just continues to turn green weekly. That's when you know your system has started to shift out of balance.

What Really Helps

Most beginners just scrub at all the glass, which gets rid of the algae temporarily but will just come back over and over if the underlying problem isn't addressed.

Before you even start, make sure to double-check these things:

• Is the light running for more than 8 hours?
• Are you overfeeding the fish? Are flakes sitting on the gravel?
• Is the filter pushing water through the tank correctly?

You don't need a perfect answer, just a check. Even the smallest of changes can impact your algae growth.

Step 1: Clean the Glass

This is where most people notice the algae, so it makes sense to clean the glass first, and honestly, it feels pretty good to look at your tank when it's sparkling.

If you have light algae build up on the glass, an easy tool to use is a magnetic algae cleaner. This saves you the effort of getting your hands wet, making it so much more likely that you will do regular cleanings, rather than avoiding them.

For the more stubborn algae on the glass, you will need a scraper. Take it slow, because if you have any sand or grit caught between your blade and the glass, it will create scratches.

Your tank will look much better at this point, even if nothing else has changed.

Step 2: Decorations and Hard Surfaces

Rocks, driftwood, and decorations will slowly begin to collect algae over time, and this shouldn't be a main concern in the cleaning of your tank. Take out the decorations that are very covered in algae and rinse them with water you have taken from the tank. A gentle scrub is normally enough. The problem many people make here is that they aim to clean everything perfectly, but we need to realize that a little biofilm growth is healthy; we are simply removing excess algae growth.

Step 3: Gravel Cleaning

This is where people typically don't clean enough. Leftover food and fish waste will sink down into the gravel and break down into the nutrients algae feed on, meaning that surface cleaning is never really going to completely solve the problem.

Using a gravel vacuum makes cleaning the gravel easy. You do not need to clean the entire tank in one go, and it's best not to. This method is usually how people turn their tanks from "clean" to "clean long-term".

Step 4: Change the Water

Once you have finished cleaning, give the tank a small water change of about 20-30% of the water. This won't upset your fish, but it will remove the excess nutrients from the water that algae feeds off and will help to make sure your algae does not re-grow as easily.

Make sure the new water is treated with a dechlorinator and is about the same temperature as the water in the tank. You'll shock the fish and give them all a shock they probably don't deserve.

Step 5: Make Sure It Does Not Re-Grow

Cleaning will help reduce the algae, but stability is the key to keeping the algae at bay.

The key is a consistent environment. Have the lights on for a regulated amount of time, don't overfeed the fish, and make sure the filter is running correctly. Live plants can also help greatly in preventing algae, as they use the same nutrients. Many aquariums thrive on this; it really is as simple as that.

If you are struggling a lot with algae buildup in a large tank, you can think about adding extra filtration.

Common Mistakes People Make and Worsen the Problem

The biggest mistake, strangely enough, is cleaning the tank too much, for example, doing too large water changes every time you clean. This is where people damage the system. Using soaps or chemical cleaners is also a big mistake; even a tiny residue can have negative impacts on your fish. Always use an aquarium-safe cleaning tool. Finally, you need to realize that you cannot get rid of algae entirely. What you want is to manage the amount in your tank.

Simple Summary

This problem is not so much a cleaning issue as a balance problem. Once you create a good system, your cleaning will not need to be as rigorous, and the algae will naturally be much less prominent in the tank. A magnetic cleaner for your glass, a gravel vacuum, and a proper light cycle will take care of 90% of the algae problem.

Final Thought

Algae seems like a problem, but really, it's feedback from your tank. When the tank is running at its optimal settings, the algae simply won't have any reason to grow. That's when your tank is perfect.