How to maintain crystal clear water

There’s nothing quite like a crystal-clear aquarium. When the water is clean, light dances through the tank, colours pop, plants thrive, and fish appear calm and confident in their environment. But achieving that clear, polished look isn’t always as simple as filling a tank and switching on a filter.

Cloudy water, algae blooms, and floating debris are some of the most common frustrations aquarium owners face. The good news? Clear water isn’t about luck it’s about understanding balance. Let’s walk through everything you need to know to keep your aquarium water consistently crystal clear.

Understand What “Clear Water” Really Means

Clear water doesn’t just mean that you can see through it. Truly healthy aquarium water is:

• Free from visible particles and haze

• Chemically stable (safe ammonia, nitrite, nitrate levels)

• Odourless and fresh-smelling

• Supportive of fish, plants, and beneficial bacteria

A tank can look clear but still be unhealthy and vice versa. The goal is clarity and stability.

Start With Proper Filtration

Your filter is the heart of your aquarium. Without it, clear water is nearly impossible.

Choose the Right Filter

Your filter should be rated for at least 5x-10x the LPH (Litre Per Hour) of the volume of water, i.e 300LPH for a 60L aquarium. It is always worth investing in a slightly larger filter than under filtering. Undersized filters struggle to remove waste efficiently and will never gain crystal clear water.

There are three types of filtration working together:

• Mechanical – removes debris and particles

• Biological – houses beneficial bacteria that break down waste

• Chemical – removes impurities like tannins or odours (optional)

We recommend to add polywool as the last form of filtration to block the small particles and any remaining debris that has bypassed the sponges.

Products such as Seachem Purigen or Dymax Clear-Mix is a fantastic media that provides clarity to water, removes tannins from wood and is easily regenerated. Each 100ml bag can support a 400L for many months.

Contrary to popular belief that sponges will last for many years before needing to be replaced, typically when they start to degrade. As we don't rely on them for biological filtration, only collecting detritus. A high surface area such as Eheim Lav or Seachem Matrix are incredible biological media for supporting your eco-system.

Maintain Your Filter Properly

A common mistake is cleaning filters too aggressively.

Best practices:

• Rinse filter media in old tank water, not tap water

• Never replace all media at once

• Clean every 4-6 weeks at a time.

• DO NOT wait until flow is reduced as this will upset the balance and cause additional issues.

This preserves beneficial bacteria that keep water clear long-term.

Master the Art of Water Changes

Regular water changes are one of the most effective ways to maintain clarity.

How Much and How Often?

• 20–30% weekly for low stocked tanks

• 30–50% for heavily stocked tanks

Water changes remove:

• Excess nutrients such as Nitrates

• Dissolved waste

• Fine particles that filters miss

Use a Gravel Vacuum

Debris often settles at the bottom of the tank. A gravel vacuum removes waste before it breaks down and clouds the water. If you have loose soil then you can syphon this also if it doesn't interfere with planting. Excess detritus is a recipe for an algae bloom.

Avoid Overfeeding at All Costs

Overfeeding is one of the fastest ways to ruin water clarity.

Why Overfeeding Causes Cloudy Water

• Uneaten food decays

• Waste levels spike

• Bacterial blooms occur

Feeding Rule of Thumb

Feed only what your fish can eat in 2minutes, every other day.

Clear water starts with controlled feeding.

Control Light to Prevent Algae Blooms

Algae is a natural part of every aquarium—but too much light fuels overgrowth.

Ideal Lighting Duration

• 6–8 hours per day for most aquariums

• Use a timer for consistency

Avoid placing tanks near windows, as natural sunlight can quickly trigger algae blooms that cloud the water and coat surfaces.

Maintain a Healthy Biological Balance

Clear tanks rely heavily on beneficial bacteria.

Cycle Your Aquarium Properly

New tanks often experience cloudy water due to bacterial blooms. This is normal during cycling. Best practice is to not water change or add any chemicals. Let it rest and the nitrifying bacteria will consume this.

Be patient:

• Avoid adding fish too quickly

• Test water parameters regularly

• Allow bacteria colonies to establish naturally

Once mature, a cycled tank becomes much easier to keep clear.

Use Live Plants to Your Advantage

Live plants are natural water purifiers.

They:

• Absorb excess nutrients such as nitrates. Nitrates are only removed by plants or water changes.

• Compete with algae

• Improve oxygen levels

• Provides shelter to fish

Healthy plant growth often leads to noticeably clearer water over time.

Don’t Overcrowd the Tank

Too many fish = too much waste.

Before adding fish:

• Research adult sizes or ask us in store

• Understand species compatibility

• Follow stocking guidelines

A lightly stocked tank is far easier to maintain than an overcrowded one. Remember, you want a feature in your home, not a population.

Address Cloudiness Quickly

If your tank becomes cloudy, don’t panic—identify the cause.

Common Types of Cloudiness

• White/milky: bacterial bloom or ammonia (Test for ammonia to be sure)

• Green: algae bloom

• Brown/yellow: tannins from driftwood

Each has a different solution, but most clear up with improved filtration, water changes, and patience. If the cloudiness is caused by ammonia, immediately carry out a 50-60% water change. Bacterial blooms often extract oxygen out of the water so it is advisable to increase oxygen dramatically, especially at night. Add Seachem Stability for 7 days to help stabilise your aquarium.

Avoid Quick-Fix Chemicals

Water clarifiers can temporarily improve appearance, but they don’t fix the root cause.

Long-term clarity comes from:

• Consistent maintenance

• Stable water parameters

• Balanced feeding and stocking

Use chemicals sparingly and only when necessary.

Create a Simple Weekly Routine

Consistency is the secret to clear water.

Weekly checklist:

• Check water clarity and fish behaviour

• Perform a partial water change 30-50%

• Clean glass

• Remove debris and dead plant matter

Small, regular actions prevent big problems. Always recommended to do all the maintenance inside the aquarium first then water change last to extract all the detritus you have loosened.

Final Thoughts

A crystal-clear aquarium isn’t about perfection it’s about balance, patience, and routine. When filtration, feeding, lighting, and maintenance work together, your tank becomes a self-supporting ecosystem that rewards you with clarity and calm.

Clear water doesn’t just look good it’s a sign that your fish are thriving.

If you ever feel stuck, remember: most aquarium problems are solved by slowing down and simplifying. Also to remember, the more money you throw at this hobby, the safer you will be in the fight against algae and imbalances. The most important place to spend your money is a quality filter that provides the turn over. Always over filter where possible.