Comparison: External Canister Filters VS Internal Sponge / Powerhead Filters:
If you are a beginner in fish keeping hobby, then you might be looking for the best filter for your aquarium. There are many choices & I can’t say which one is better for your aquarium because every filter has its own pros & cons. A variety of filters are sold in the fish stores & it is difficult to make any choice unless you look at your aquarium requirements, types & quantity of fish you are keeping, & how much current you want your filter to produce. Filters are usually used for 3 purposes: filtration, oxygenation & water circulation.
Every filter has the basic purpose of cleaning solid waste particles in the water using its mechanical filtration media, & then bio media wipes out toxic chemicals that are released from fish waste, leftover food, & other detritus that would otherwise pollute the water.
Canister Filter:
Canister filters require setup of both inflow & outflow hoses inside the aquarium. It draws water using an inflow hose, & then water flows through the canister filter. An internal tube inside the filter pushes water towards the base of the filter, & then water rises upward through the filter media that cleans the water & pushes it back to the aquarium via an outflow hose. A water pump is used for pushing water back to the aquarium which creates suction inside the canister filter, & it starts drawing water from the aquarium using an inflow hose.
Canister filters come with their own media but there is not enough media inside the canister filters to fill the baskets. You can customize filter media inside the canister filters by adding your own media.
Internal Filter:
Internal filters come with their own media so there is no need to customize it & add your media inside the filter. Attach your internal filter against the aquarium side & turn on the power. Also, you can attach an air tube to the nozzle of the filter & place the opposite end of the air tube outside water for adding air bubbles in the water. Some filters have an adjustable air flow plate that allows you to point the filter in any direction. So, if you point the internal filter towards the aquarium top, then you can oxygenate water due to surface agitation.
Internal sponge filter produces air bubbles when it is connected to an air pump. Release of air bubbles creates suction inside the sponge filter, & it starts sucking water from the outside of the filter. Water flows into the filter through the sponge that traps fish waste & other debris.
Canister Filter VS Powerhead Filter VS Sponge Filter
Aeration: Internal Powerhead / Sponge Filters VS External Canister Filters:
If you want to oxygenate water, then you can use an internal filter operated by an air pump that produces bubbles & causes surface agitation when bubbles hit the water surface to add atmospheric oxygen in the water. Also, internal powerhead filters are used for oxygenating water by positioning the nozzle towards the water surface & attaching an air tube to the nozzle to add bubbles in the water. This causes lots of disturbance in the water for adding atmospheric oxygen in the water.
Canister filters return water using a spray bar that causes disturbance at the surface of water that aerates water.
Water Circulation: Internal Filters VS External Canister Filters:
Water circulation is very important because fish waste sticks in the substrate & unless you have a powerful filtration, you can’t take out the solid particles from the substrate.
It is very important to install the internal filter on one side of the aquarium & point it towards the water surface so that it causes surface agitation & oxygenates water. If you attach an internal filter on the right side of the aquarium, then it will push water towards the top left side, & suck water from the bottom left side, that will cause circulation in the water.
Canister filters have inflow & outflow pipes. Setup inflow pipe on one side of the aquarium, & outflow pipe on the opposite side. Water will be sucked via an inflow pipe & returned using an outflow pipe as both of them are located on the opposite sides so it will cause water circulation.
Cleaning: Internal Powerhead / Sponge Filters VS External Canister Filters:
Canister filters clean water more effectively & fast because it is working with lots of water, & there are heaps of filter media inside the canister filter. Water flows through coarse, medium & fine foams, then it flows through heaps of bio media, & finally it is pushed back to the aquarium.
Internal filters are not very efficient in cleaning water & many aquarists keep them as secondary filters inside the aquarium. They do not draw lots of water like canister filters, & they have less media compared to canister filters.
Sponge filters are very efficient in biological filtration because the sponges produce heaps of surface area for the growth of good bacteria.
Setup: External Canister Filters VS Internal Powerhead / Sponge Filters:
Canister filters need lots of work for installation & maintenance. It requires setting up inflow & outflow pipes, which need effort. Also, it needs setting up heaps of filter media inside the canister filter baskets.
There is no need to setup any attachment for internal filters because it can be used quickly after unboxing. It takes no more than 1 minute to install the internal filter inside your aquarium. All media is installed inside the internal filter, so just attach it to an aquarium side & turn on the power to start the internal filter.
Place your sponge filter in one corner of the aquarium. Connect an air tube to an air stone placed inside the sponge filter. It will create suction inside the sponge filter & will suck water from the outside. Air stone will increase the number of bubbles produced by the filter & will lower the noise of air bubbles. Sponge filters are most popularly used in fry tanks because they do not suck fish babies.
Customization: External Canister Filters VS Internal Powerhead / Sponge Filters:
Every canister filter can be customized differently depending on which media you are using inside the filter & what is the order of the media.
Internal filters do not need customization of filter media so most of the aquarists do not add their media inside the filter & do not alter the order of media.
Sponge filters usually use its sponge for both mechanical & biological filtration. Heaps of beneficial bacteria grow on the large surface of the sponge. Some sponge filters contain small containers for storing bio media too.
Maintenance: External Canister Filters VS Internal Powerhead / Sponge Filters:
Filling every filter basket with media needs time & effort. Also, a canister filter needs lots of maintenance because it requires cleaning up heaps of filter media. Overtime both internal & external pipes need cleaning, as well as filter impeller needs cleaning too. Cleaning process of the canister filter is time consuming & difficult because the filter needs to be opened, cleaned, & setup again, & in this process you should not lose lots of good bacteria. Clean your canister filter with aquarium water because tap water will kill all good bacteria in your canister filter.
Internal filters need low maintenance because it requires turning off the power, taking out the filter, opening the filter, cleaning its sponge, putting back everything in the filter, & finally install it again in the aquarium.
It is very easy to maintain sponge filters. Coarse sponges do not get clogged easily as compared to fine sponges. It is simple to clean the sponge filter because it requires taking out the sponge & squeezing it in a bucket of aquarium water for up to a minute, & installing sponge back in the filter.
Media Replacement: External Canister Filters VS Internal Sponge / Powerhead Filters:
In canister filters, usually mechanical filter media overtime needs replacement which could cost a little money. Canister filters use coarse, medium & fine foams. When foams are clogged then they need replacement.
Internal filters usually come with a high-quality sponge that works for a longer period of time.
Sponge filters also over time need replacement. But if you are using high quality sponge, as well as your sponge is coarse then it will not get clogged easily as compared to fine sponge.
Placement: External Canister Filters VS Internal Filters:
Canister filters are located outside of the aquarium, & they use inflow & outflow pipes for drawing water from the aquarium & pushing water back to the aquarium.
Internal filters are located inside the aquarium at a corner, & they suck water from the bottom & release water from the outflow at the top.
Cost: External Canister Filters VS Internal Sponge / Powerhead Filters:
Canister filters are more expensive than internal filters. They usually have high running costs too because they need more power for pumping heaps of water outside of the aquarium into the canister filters which ensures very efficient cleaning.
Running cost of internal filters is usually low because they are not usually working with lots of water so they are not very efficient in cleaning.
Sponge filters are cheap. Running cost of sponge filters is low because they are usually operated with a low power sponge.
Easy to Use: External Canister Filters VS Internal Powerhead / Sponge Filters:
Beginners usually prefer to setup filters that require less information for setting up & maintenance. Internal filters only require attachment to the aquarium side, & then connect filters to the power to clean aquarium water.
It is very easy to setup sponge filters. It only requires connecting an air tube to the air stone inside the sponge filter & powering on the air pump will make the filter work.
Canister filters need lots of knowledge about setting up the mechanical & biological media. It requires customization of the filter media inside the filters depending on your aquarium water & fish needs. Also, it requires setting up both inflow & outflow hoses, finding a suitable place for the placement of the bulky canister filter, & then powering it on. Maintenance of canister filters requires more knowledge so that you can efficiently clean the filter without losing too much beneficial bacteria.
Appearance: External Canister Filters VS Internal Powerhead / Sponge Filters:
People usually do not like the look of the filter. External canister filters are located outside of the aquarium so they are not visible. Only inflow & outflow pipes are located inside.
Internal filters are located inside the aquarium so they do not look good. Nobody likes the appearance of sponge filters inside the aquarium. People usually hide internal filters behind decorations, plants or any other structure.
Space: External Canister Filters VS Internal Sponge / Powerhead Filters:
Canister filters do not take space inside the aquarium so there is enough swimming space for the fish. However, they are bulky & take lots of space outside the aquarium.
Internal filters take some space inside the aquarium. But they are usually smaller than canister filters.
Sponge filters only need a little space inside the aquarium.