Aquaclear Power Filter Customization

Fanboy, I am, on the Aquaclear (AC) line of aquarium power filters, specifically the AC20 to AC70 line. Not only are they reliable and serviceable, they are very flexible and easy to tailor to your specific tank needs. While there are some issues with noise, if you do regular filter maintenance you will be rewarded with stellar performance. There are a few customizations you can do that will make these filters even more flexible.

All AC20 to AC70 filters use the same exact motor but with different impellers (motor blade assembly). Since the AC line has been around for such a long production run, used units are commonly available. This greatly simplifies looking for spare parts. The AC motor uses magnetism to move the impeller around and therefore has only one moving part. The only moving part in the filter is the impeller. This simplicity greatly simplifies maintenance.

Maintenance on the AC line requires you to take the filter apart for cleaning. Here are the steps:

  1. Lift the basket out and clean your media and sponge in used tank water. The media and sponge have beneficial bacteria (BB) essential to the health of your fish. Washing these in tap water that has chlorine or chloramine, which is true for all large cities, will kill the BB and therefore hurt your fish, so do not use tap water.
  2. Remove the intake tube and wash it. You can use a small toothbrush to remove algae. A baby bottle brush also works.
  3. Remove the filter body from the tank and dump the water and any floating particulate. Clean the sludge at the bottom of the filter body
  4. Grasp the filter body from the back so that the filter “waterfall” points away from you. The black box on the lower right side is the motor. Turn the motor 1/4 turn to the right to remove it. There is an arrow imprinted onto the filter motor. You cannot turn it to the left because the filter body will block this direction, so you cannot make a mistake. This is good design. After rotating the motor wiggle the motor and it should drop out of the bottom.
  5. On the filter body remove a grey piece of plastic that separates the motor section from the filter body. Just put your finger into the hole and pull it up. Clean and replace this.
  6. Carefully remove the impeller. The impeller is held in by magnetic force. Though loose and free spinning it and might want to not come out. You could carefully use a needle nose plier in a very gentle way to remove it. The blades are breakable so be careful. A broken blade will mean replacing the impeller assembly. Clean the impeller with a toothbrush. Clean the motor well with a cotton swab or a piece of thin cloth.
  7. Some people put a dab of petroleum jelly onto the tip of the impeller shaft just before reinserting the impeller. This is to reduce the noise of the filter, to make the filter more quiet. I have had mixed results with this. Replace the now clean impeller.
  8. Reinstall the motor, and the basket. Put the filter onto your tank and reinstall the intake tube, add water to prime the filter and plug it in. Reinstall the filter cover and you are done.

Customizations: Each AC impeller comes with its correspondingly sized filter body. For example the AC20 impeller and motor comes with the AC20 body. This is good for most people but if you want more biomedia in your small tank you could use a larger filter but this will increase the turbulence in your tank and might tire out your small fish. You may also want a second filter in your tank for backup and to increase the amount of biomedia but not want to increase turbulence. If you have a small tank and do not want the larger turbulence of the bigger filter, you can buy that bigger AC filter and change the impeller to one from a smaller AC filter. The result is a larger filter body with more space for biomedia and sponge but with the lower turbulence of the smaller filter. You can do this because all AC20s to AC70s use the same motor but different impellers. Stepping down to a smaller impeller creates less turbulence.

Yes, all ACs have an adjustment for lower or higher water flow. This works to a point, after which the filter still has a minimum throughput. Stepping down the impeller reduces this even more, giving you more flexibility.

Model Impeller part # Max/Min output (GPH) Impeller blade size # Impeller blades
20 A-630 100/33 4×4.5mm 4
30 A-632 150/50 4x6mm 4
50 A-634 200/67 5x8mm 4
70 A-636 300/100 6x6mm 6

To further reduce the flow of any AC you can add a sponge prefilter to the input. Get an appropriately large sponge, saturate it in water and freeze the sponge. Once frozen it is now easy to use an electric drill to hollow out the hole for the input tube. Drilling an unfrozen sponge is difficult because the sponge will grab the drill bit and therefore not hollow out.

The output of any AC can also be reduced. Some fish do not like the waterfall effect of the AC, so this can be reduced dramatically. The easiest way to reduce this waterfall effect is to raise your water level to just under the AC filter’s output lip. You could also get an elastic band and put it around the output spout of the AC. You can then use a piece of material such as tulle. Synthetic material will not degrade as fast. Loop the material over the elastic band, letting the material hang into the water. The water will first flow onto the material and then into the water, resulting in less water turbulence. Less water turbulence also results in less oxygenation of the surface water, so some splashing of the waterfall is beneficial for your fish.

While these customizations are small, they add great flexibility to an already reliable and maintainable power filter. Go buy used AC parts and start customizing.

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