Best Undergravel Fish Tank Filter: Top Picks for Clean and Clear Water

When it comes to keeping your aquarium clean and healthy, choosing the right filter is crucial. Undergravel filters are a popular choice for many aquarium enthusiasts due to their effectiveness and affordability.

But with so many options on the market, it can be overwhelming to choose the best one for your tank. 

In this blog post, we’ll take a look at the top picks for the best undergravel fish tank filter that will keep your aquarium water clean and clear.

Best Undergravel Fish Tank Filters

If you’re looking for a reliable and efficient way to keep your aquarium clean, an undergravel fish tank filter is an excellent choice. 

These filters work by pulling water through the gravel at the bottom of your tank, which helps to remove debris and waste. Here are our top picks for the best undergravel fish tank filters.

1. Penn-Plax Undergravel Aquarium Filter

This filter is air driven, which means there are less moving parts to maintain. It’s also suitable for most 40-55 gallon aquariums and provides biological, chemical, and physical filtration. Additionally, it aerates your tank while filtering, making it a 2-in-1 solution.

However, keep in mind that an air pump is not included, and some users have reported issues with the tubes. Also, this filter may not be suitable for larger tanks.

Overall, if you’re looking for a simple and reliable undergravel filter, the Penn-Plax Undergravel Aquarium Filter is definitely worth considering.

Pros

• Utilizes air pump for crystal clear water
• Provides biological, chemical, and physical filtration
• Aerates your tank while filtering

Cons

• Air pump not included
• Some users reported issues with the tubes
• May not be suitable for larger tanks

2. Penn-Plax Undergravel Aquarium Filter

If you’re looking for a simple and easy-to-maintain undergravel filter for your 10-gallon aquarium, the Penn-Plax Undergravel Aquarium Filter is a great option.

This undergravel filter is suitable for most 10-gallon aquariums, and is safe for freshwater and saltwater setups. It includes 2 filter plates, 2 adjustable lift tubes, 2 straight airline tubes, 3 filter plate connectors, and 2 replaceable Filt-a-Carb Activated Carbon Media Cartridges.

The filter plates are 9.5” (W) x 9.5” (D) each, and together they measure 19” (W) x 9.5” (D). Each lift tube at filter plate base is 9.75–12.75”. The Clear-Free Premium Under Gravel Filter is a product of Penn-Plax, a manufacturer and distributor of top-quality pet supplies.

Pros

• The air-driven system utilizes an Air Pump to cycle crystal clear water throughout your aquarium, making for simplistic and easy maintenance.
• The filter provides biological, chemical, and physical filtration, allowing both air and water to pass through the Filt-a-Carb Activated Carbon Cartridges.
• The filter also aerates your tank, making it a filter and bubbler in one.

Cons

• The air stones may not work properly and may leak air only at the top of the air stone.
• Some users have reported that the tubes came cracked upon delivery.
• The filter may not fit properly in some tanks.

3. Penn-Plax Filt-a-Carb Replacement Activated Carbon Media Cartridges

You may want to consider Penn-Plax Filt-a-Carb Replacement Activated Carbon Media Cartridges as a replacement filter media option for your undergravel fish tank filter.

Penn-Plax Filt-a-Carb Replacement Activated Carbon Media Cartridges are a great option if you’re looking for a replacement filter media for your undergravel fish tank filter. 

They’re designed to fit the lift tubes of Muti-Pore and Undergravel “E” filters, and they’re effective at absorbing ammonia, nitrites, nitrates, and phosphates. 

Plus, they also remove harmful chemicals and toxins, clear up discolorations, and reduce foul odors from your tank. 

However, they’re designed for old school undergravel aquarium setups, and you may need to replace them more frequently depending on the size of your tank and the number of fish you have.

Pros

• Made to fit the lift tubes of Muti-Pore and Undergravel “E” filters, serving as a replacement for when it’s time to cycle out aquarium filter media.
• In addition to absorbing ammonia, nitrites, nitrates, and phosphates in a timely manner, these Activated Carbon Cartridges also remove harmful chemicals and toxins, clear up discolorations, and reduce foul odors from your tank.
• These Activated Carbon Cartridges come together in a 2 Pack. For best results, replace cartridges every 2 to 4 weeks. They’re lightweight, disposable, and are safe for Freshwater and Saltwater aquariums.

Cons

• There has been a burst of growth, development, and ingenuity within the aquatic industry, and although Penn-Plax is a part of this as well, these cartridges are designed for old school undergravel aquarium setups.
• Although these cartridges are designed to last 2 to 4 weeks, you may need to replace them more frequently depending on the size of your tank and the number of fish you have.
• Some customers have reported that these cartridges don’t fit their filter properly, so it’s important to double-check the dimensions of your filter before ordering.

4. Penn-Plax Clear-Free Premium Under Gravel Aquarium Filter

The Penn-Plax Clear-Free Premium Under Gravel Aquarium Filter uses an air pump to circulate crystal-clear water and keep your aquarium clean.

It’s suitable for most 20-29 gallon aquariums and is safe for both freshwater and saltwater setups. The filter provides biological, chemical, and physical filtration by gently suctioning water through gravel and the filter plates, allowing both air and water to pass through the Filt-a-Carb Activated Carbon Cartridges. 

When water continues to be drawn through, anaerobic bacteria collects and colonizes within the gravel and filter plates.

The filter is air-driven through the use of Air Stones and an Air Pump (not included), which also aerates your tank. In essence, your aquarium is being filtered and aerated at the same time, through the same system. 

The Clear-Free Premium Under Gravel Filter includes 2 Filter Plates, 2 Adjustable Lift Tubes, 2 Straight Airline Tubes, 3 Filter Plate Connecters, and 2 Replaceable Filt-a-Carb Activated Carbon Media Cartridges.

Pros

• This filter is air-driven, which means there are fewer moving parts and it’s easy to maintain.
• It provides biological, chemical, and physical filtration, which helps keep your aquarium water clean and clear.
• It also aerates your tank, providing both filtration and aeration in one system.

Cons

• The filter plates may not be wide enough for some tanks.
• Some users have reported that it takes longer to stabilize than other types of filters.
• You may need to modify the filter to get the correct flow under the grid.

5. CORISRX Undergravel Filter

The CORISRX Undergravel Filter is easy to install and can be connected to different types of pumps to increase circulation and filtration. However, some users have reported that the filter may not be very sturdy and could be prone to breaking. 

Additionally, food can slip through the pebbles and create a mess at the bottom of the tank. The air stones may not be very effective and could need to be replaced. 

Pros

• The filter circulates the water under the gravel layer to reduce gravel corruption.
• The gravel bed provides a large surface area for Nitrobacteria, which keeps your water crystal clear.
• The filter plate can be connected to different types of pumps to increase circulation and help with mechanical and chemical filtration.

Cons

• The filter may not be very sturdy and could be prone to breaking.
• Some users have reported that food can slip through the pebbles and create a mess at the bottom of the tank.
• The air stones may not be very effective and may need to be replaced.

6. Emma Mall Aquarium Powerhead

This aquarium powerhead is fully submersible and has a maximum flow rate of 158 gph (600L/h), making it suitable for most small to medium-sized aquariums. It’s also energy efficient and super silent, so it won’t disturb the peace and quiet of your aquatic pets.

Installation is simple, and it can be used with an undergravel filter to create a natural and healthy fish and plant environment. Safe and durable, it won’t break down or malfunction.

The maximum flow rate may be insufficient for larger tanks, and the cable length may be inadequate for some installations. The soft hose and air valve may also not be of the highest quality and need to be upgraded.

Pros

• Easy to install
• Suitable for both fresh and saltwater aquariums
• Energy efficient and super silent

Cons

• Maximum flow rate might not be sufficient for larger tanks
• Cord length might be too short for some setups
• Air valve and soft hose might not be the best quality

7. XMHF Aquarium Undergravel Filter

The XMHF Aquarium Undergravel Filter is a great option for those on a budget who are looking for an easy-to-use filter. 

The filter is precisely made and easy to assemble, and the 7-layer, 28-piece filter board is made of excellent material and is easy to clean. Additionally, the filter comes in different sizes to fit a variety of fish tanks.

However, the filter may be too small for larger tanks, and some users have reported that the filter can be flimsy. 

The filter also might not be as efficient as some other, more pricey alternatives. In conclusion, the XMHF Aquarium Undergravel Filter deserves some thought if you need an undergravel filter for your aquarium and are on a tight budget. 

Pros

• The filter is precisely made and smoothly buckled, making it easy to assemble and disassemble.
• The 7-layer, 28-piece filter board is made of excellent material and is easy to clean.
• The filter comes in different sizes to fit a variety of fish tanks.

Cons

• The filter may be too small for larger tanks.
• Some users have reported that the filter can be flimsy.
• The filter may not be as effective as more expensive options.

Buying Guide

When it comes to choosing the best undergravel fish tank filter, there are several important factors to consider. We’ve compiled a list of features to look for when making your decision.

Tank Size and Compatibility

Before purchasing an undergravel filter, it’s important to consider the size of your aquarium. 

Undergravel filters are best suited for smaller tanks, typically up to 55 gallons. Additionally, make sure the filter is compatible with your specific tank type, whether it’s freshwater or saltwater.

Material and Durability

Undergravel filters are typically made of either plastic or glass. While plastic filters are more affordable, glass filters tend to be more durable and long-lasting. 

Look for filters with sturdy construction and high-quality materials to ensure they can withstand the wear and tear of regular use.

Flow Rate and Filtration Capacity

The flow rate and filtration capacity of an undergravel filter are crucial factors to consider.

The flow rate determines how quickly the water is circulated through the filter, while the filtration capacity refers to how effectively the filter removes waste and debris from the water. 

Look for filters with adjustable flow rates and high filtration capacities to ensure optimal water quality.

Ease of Maintenance

Finally, consider the ease of maintenance when choosing an undergravel filter. Look for filters with easy-to-clean components and simple assembly. Make sure replacement parts are readily available and affordable.

By considering these factors when choosing an undergravel fish tank filter, you can ensure that you select the best product for your aquarium and your fish.