How To Clean The Sides Of A Glass Or Acrylic Aquarium 

To clean the sides of an aquarium, a hobbyist must first know if they have a glass or acrylic tank. Both materials need different tools for cleaning.

Glass is harder to scratch, meaning almost any device is fine. Acrylic is soft and easy to scratch — aquarists must use softer tools and be more careful.

Algae sponges, razor scrapers, aquarium magnets, and automatic cleaners work for glass aquariums.

Mr. Clean Magic Erasers, plastic scrapers, and aquarium magnets work for acrylic aquariums. While aquarists want to avoid scratches, buffing out scratches and scuffs is possible.

Leave the water in the tank when cleaning the inside of an aquarium, glass, or acrylic. The algae falls from the tank’s sides to the aquarium’s bottom. Use a gravel vacuum to clean the substrate after cleaning the sides of the aquarium to get all the algae.

To clean the outside of an aquarium, hobbyists want to use a soft microfiber cloth. Plain water or vinegar solutions are both safe for cleaning.

Vinegar also works wonders on limescale buildup caused by hard water.

Aquarists with acrylic aquariums can use liquid acrylic polishers to clean their tanks.

NEVER use household cleaners as they contain dangerous chemicals.

Limiting algae buildup is possible by reducing the water’s nutrients.

Limit the lighting, avoid overfeeding, and don’t overcrowd the tank. Do a water change and lessen the phosphates and nitrogen. Aquarists can also try switching to reverse osmosis (RO) water or adding live plants.

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Cleaning The Inside Of A Glass Aquarium

Smaller aquariums are often made of glass. Glass is harder and more difficult to scratch. It’s much easier to clean glass since razors and other sharp materials won’t damage it.

Use A Sponge For Softer Algae

The easiest way to get rid of soft algae is to use an aquarium-safe sponge.

Fish stores sell plain sponges for super cheap for scrubbing aquariums. The downside is that aquarists must stick their hands in the tank and get wet.

Fish stores sell sponges attached to long handles for those who prefer to avoid getting wet. These are especially useful for larger tanks too deep for a person’s arm to reach the bottom.

It is entirely safe to clean the inside of the fish tank while the fish are still in it. They may become somewhat stressed, though it’s a quick process, and they’ll usually find a place to hide.

Use A Scraper For Tougher Algae

Some types of algae are too tricky to remove with a regular algae sponge. Buy an aquarium scraper instead, which contains a sharp razor for removing hard algae.

Be sure to buy a scraper designed for glass, not acrylic. Acrylic scrapers may not be tough enough to remove algae from glass.

Hold the razor at a 45-degree angle to get it to work the best.

Be careful when scraping. Remember that the scraper contains a sharp razor that can easily cut skin.

Some scrapers contain a razor on one side and a hard bristle brush on the other. They are useful for cleaning decorations as well as the sides of the tank.

Use An Aquarium Magnet

Aquarium magnets work excellently for getting large spots of soft algae in a tank.

They may work for more problematic algae. Scrapers are often the only things effective on tough algae.

Some pricier magnets come with scraper attachments to clean off tough algae.

Aquarium magnets come in many sizes, from small to large, for differently sized tanks.

The downside to magnets is that it can be hard to get to smaller, difficult-to-reach spots.

How An Aquarium Magnet Works

The magnet comprises two pieces: one goes on the inside of the aquarium, and one goes on the outside.

The piece that goes on the outside of the aquarium is covered in soft material to polish the glass.

The piece that goes on the inside of the aquarium is covered in hard plastic pieces. Those pieces scrape at the algae as the aquarist drags the magnet across the tank.

The magnets inside each piece keep the two pieces together. The aquarist simply holds onto the outside piece. They move the device along the sides of the tank to remove algae.

Aquarium Magnet Tips

Be careful not to get too close to the substrate. Pieces of the substrate may get stuck inside the pads of the scraper. The abrasive pieces of substrate are often strong enough to scratch the tank.

Remove the magnet after cleaning, and rinse it off with fresh water. Store it somewhere dry when not in use.

Many of these magnets also float, making them easy to get out of the tank if the two halves separate.

Be sure to buy a magnet made for glass aquariums rather than acrylic. The magnets are stronger for glass aquariums — they must stick to each other.

Glass and aquarium magnets also comprise different scraping materials.

Use An Automatic Cleaner

Automatic cleaners free up time and energy. They are useful for those who don’t want to scrub their aquarium by hand or have trouble doing so.

These are very effective and act similarly to magnets.

The aquarist needs to simply turn the cleaner on, and it travels about the tank, scraping off the algae.

These devices typically come with rechargeable batteries and replaceable algae pads.

Although they are great, automatic cleaners aren’t practical for most hobbyists. They are expensive, usually over $200.

Another downside to these cleaners is that they still need some hands-on use. They can’t maneuver corners, meaning the aquarist must move it to different sides of the tank.

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Cleaning The Inside Of An Acrylic Aquarium

Acrylic aquariums are more common for large aquariums. Acrylic is stronger and more flexible, making it great for holding lots of water. It’s less prone to shattering and leaking and can be fashioned into many shapes.

The problem with acrylic is that it’s far easier to scratch than glass. The above cleaning methods aren’t always safe for acrylic.

ALWAYS use products designed for acrylic aquariums. Many of the products made for cleaning glass come in a similar product made for acrylic.

Always try new products on a small area of the tank before using it, even if it says it’s “acrylic-safe.”

Avoid scrubbing the sides of acrylic aquariums too roughly, even if something is hard to get off. Switch to a more effective product rather than using force.

DO NOT Use An Algae Sponge

Unlike glass aquariums, using an aquarium sponge on an acrylic aquarium is not a good idea. The sponge material is too abrasive for acrylic and can easily cause scratches.

Use A Mr. Clean Magic Eraser

Rather than a regular sponge, use a Mr. Clean Magic Eraser or similar melamine sponge.

These sponges are ultra-soft and contain no chemicals that can harm the fish. Despite being super soft, they are among the best materials for removing tough algae. They also work well for cleaning the outside of the tank.

These sponges comprise an inert, non-toxic material with no harmful chemicals. Split the sponge in half and use it repeatedly — simply let it dry between cleanings.

The sponges degrade over time and need replacing. They can withstand many uses and are super cheap.

Use A Plastic Scraper For Tougher Algae

Like glass aquariums, aquarists can use scrapers to remove tough algae.

Rather than the scraper containing a super sharp razor, it comprises plastic. The plastic is hard enough to scrape away the algae, though soft enough not to scratch the sides of the aquarium.

Use An Aquarium Magnet

Aquarium magnets work as well for acrylic aquariums as they do for glass aquariums.

Make sure to buy the magnets designed for acrylic aquariums, not glass ones. The ones made for acrylic aquariums comprise softer materials that won’t scratch.

How To Buff Out Scratches On An Acrylic Tank

Aquarists can use professional products to buff out scratches or scuffs. Take exceptional care not to get the chemicals in the water, or they may kill the fish.

Empty the tank of water and fish to remove scratches on the inside walls.

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Cleaning The Outside Of An Aquarium

Never use chemicals when cleaning the sides of an aquarium, even the outside. There is always the risk of getting some chemicals inside the tank.

Some dangerous substances to avoid are Windex, soap, or any other spray cleaner. NEVER spray these substances on the tank.

Some aquarists spray the cleaner onto a rag and then wipe down the outside of the aquarium. Although this is safer than spraying the tank, there is still the chance for the chemicals to get in the water.

Many of the chemicals are toxic enough to kill fish and invertebrates directly.

Others may be less harmful to livestock, though they kill off the beneficial bacteria in the tank. The ammonia and nitrites are likely to spike if enough of the bacteria dies, which can kill the livestock.

Rather than risking the aquarium with chemicals, use water, vinegar, or aquarium-safe substances.

Safe Cloths To Use

Make sure to use products that are safe for the tank material (i.e., glass or acrylic).

A soft microfiber cloth is excellent for gently wiping away film or water spots. They are safe for both glass and acrylic aquariums.

Newspapers, coffee filters, and paper towels also work excellently for cleaning glass aquariums.

DO NOT use newspapers, coffee filters, or paper towels on acrylic aquariums. The paper is too rough and is likely to scratch the material. Stick to a microfiber cloth.

DO NOT use any ammonia-based products on the outside of acrylic aquariums. It burns and stains the material. Instead, stick to plain water, vinegar, or liquid polish.

Plain Water

Regular freshwater is often enough to clean the outside of an aquarium.

Freshwater can even be effective for removing hard water buildup on aquariums. Gently pat the buildup with a damp cloth until the buildup begins to dissolve.

Water & White Vinegar Solution

A 50% freshwater and 50% white vinegar solution works great when plain water doesn’t do the trick.

Vinegar is non-toxic; while aquarists shouldn’t aim to get it inside the tank, a little bit of spray won’t hurt.

Spray the solution directly on the glass, or spray it onto a cleaning cloth and wipe the aquarium.

Liquid Polish

Some liquid polishes are safe for use on the outside of acrylic aquariums. Use these cleaners on a microfiber cloth to make the outside of the aquarium sparkling clean.

These cleaners also reduce the static electricity on the surface of acrylic tanks. They prevent dirt, lint, and other debris from sticking to the acrylic, making it look nicer for longer.

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How To Get Rid Of White Residue On The Glass

White residue sometimes builds up on the inside or outside of aquariums. It is likely a limescale buildup.

Limescale appears as the water evaporates and is most common with harder water. Limescale is a combination of calcium carbonate and ions.

The white residue is entirely harmless to aquatic life and humans, though it is unpleasant to look at.

Use A Vinegar Solution

Vinegar works exceptionally well in getting rid of this calcium buildup.

Spray the outside of the tank with a 50/50 solution of fresh water and vinegar and allow it to sit for a few minutes. Letting it sit for a few minutes gives the vinegar enough time to break down the deposits. After a few minutes, it’s usually easy to wipe the deposits away.

Using Vinegar Solutions On The Inside Of The Tank

Aquarists can also use the same solution for the inside of the tank with a little more care. Limescale residue is more likely to build up inside the tank than outside.

Rather than spraying the tank directly, spray the solution on a paper towel or cloth. Use enough to dampen the paper towels thoroughly.

Wipe the white residue with the damp paper towels.

Where possible, allow the paper towels to sit on the residue for a few minutes. After soaking for a few minutes, the residue should be easy to wipe away.

Scrubbing with a more abrasive algae sponge may be necessary after soaking.

Other Hard Water Removers

Fish stores sell aquarium-safe hard water removers, like Lime Away, that work well. These are sometimes necessary for really tough residue.

Preventing Buildup

To prevent buildup, first, determine whether the fish need hard water or soft water. New aquarists don’t always know to check the hardness.

Decrease the water hardness if the fish species prefer soft water. The hard water isn’t healthy for them in these cases, anyway.

It can be challenging to prevent buildup in a hard water aquarium in which fish need hard water.

The best thing aquarists can do is limit evaporation. Keep an eye on the tank’s water level and top it off as soon as the water level begins dropping. Keeping the water level consistent is excellent for reducing limescale buildup.

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Extra Tip For Getting Rid Of Algae — Try Algae Eaters

Those with trouble with algae can invest in living algae eaters to help keep the tank clean. Some fish and invertebrates love feasting on algae and are happy to clean the sides of the tank.

Despite being algae eaters, these animals can rarely keep an aquarium completely clean. Aquarists must still do some manual cleaning.

It’s also necessary to feed these animals even if there is lots of algae in the tank. They need various nutrients that they can’t get from food alone. Bottom feeder pellets and shrimp flakes are some of the most popular foods.

Always research the species before bringing them home to the tank.

Some algae eaters grow large and are unsuitable for smaller tanks. Some, like common plecos, become more aggressive and eat less algae as they age.

Ensure the algae eaters can safely live with the tank’s other inhabitants before buying them.

Here are some examples of good freshwater algae eaters:

• Amano shrimp
• American flag fish
• Bristlenose plecos
• Cherry shrimp
• Hillstream loaches
• Malaysian trumpet snails
• Mollies
• Nerite snails
• Otocinclus catfish
• Ramshorn snails
• Rosy barbs
• Siamese algae eaters
• Twig catfish

Here are some examples of good saltwater algae eaters:

• Bristletooth tang
• Coral-banded shrimp
• Foxface
• Kole tang
• Lemon peel angelfish
• Quoyi parrotfish
• Scarlet hermit crabs
• Sea hare
• Turbo snails
• Tuxedo urchin

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How To Prevent Algae Buildup

Algae builds up due to an excess of nutrients. An aquarist must limit the nutrients in the tank to prevent algae buildup.

Don’t Leave The Lights On For Too Long

Too much light is one of the most common causes of excess algae growth in an aquarium.

While fish, invertebrates, and plants all need light, there is such a thing as too much light.

To avoid too much lighting, only keep the aquarium light on for six to eight hours daily. It is enough time for the plants to photosynthesize and the fish to enjoy the light. The natural lighting from around the house is usually enough for the rest of the day.

NEVER leave aquarium lights on overnight. Not only does this encourage algae growth, it is bad for fish and invertebrates.

These critters need a natural day-night cycle, as most animals do. Having the light on all day and night causes stress, which can lead to illness.

Keep the aquarium away from windows. While natural filtered light is okay, direct sunlight causes algae to pop up rapidly. Direct sunlight is also dangerous because it can cause temperature fluctuations.

Don’t Overfeed

Overfeeding is one of the primary causes of too many nutrients in the tank. New aquarists, especially, are prone to overfeeding their fish. The uneaten food breaks down, causing excess nutrients in the water that feed the algae.

The amount of food an aquarist must give their fish depends on the species. As a general rule, only feed fish what they can eat in two to three minutes. Remove extra food after this timeframe.

Don’t Overcrowd The Tank

Overcrowding is another common cause of excess nutrients. The fish constantly produce too much waste.

Only keep as many fish as the tank can safely hold.

Try Adding Live Plants

Live plants absorb nutrients to stay healthy and grow. They can reduce the amount of algae in an aquarium.

Reduce The Phosphates & Nitrogen In the Tank

Phosphates and nitrogen are notorious for feeding algae growth.

Saltwater aquarists should check their saltwater mixes for nitrogen and phosphates. Only buy saltwater mixes that don’t contain these elements to reduce the amount of algae in the tank.

Change The Water

It’s also possible to reduce the amount of nutrients in the water by doing more frequent water changes. For example, try doing a water change every week rather than every other week.

NEVER replace all the water at once, as doing so can shock the fish. Aim to replace 15-30% of the water at a time.

Use Reverse Osmosis (RO) Water

To reduce the nutrients going into the tank, use reverse osmosis (RO) water rather than tap water. RO water is nutrient-free and keeps the aquarium at a neutral 7.0 pH.

The problem with tap water is that it contains nutrients and minerals that feed algae.

Aquarists can get RO water from grocery stores, fish stores, or at home.

RO water is readily available at the grocery store, though it’s usually more expensive.

Many specialty fish stores sell RO water in larger increments. It’s cheaper than getting it from the grocery store. Hobbyists must usually bring their own bucket and lug the heavy water home.

Installing an RO filter at home is the most convenient way of getting RO water. These filters can be expensive, though they quickly pay for themselves in the long run. The aquarist always has fresh RO water mere feet from their aquarium.