These are 100% American (USA) made with as much as 5 times the capacity of a given sponge size over similar appearing Chinese knock offs.
While these knock-offs utilize and violate the patent design often changing only the color to green or black while these Chinese made sponges are vastly inferior, as well as often only available in coarse or fine, but not both or combos.
Why purchase products made outside North America for an inferior sponge product to save maybe $1 to $2 and help perpetuate copying of patented USA products?

Capable of moving more water than other sponge filters.

Made from Proprietary Patented Sponge Foam for the highest mechanical debris capacity and bio capacity; generally as much as FIVE TIMES THE CAPACITY of other non Patented Sponge Filters!!!

NO other sponge filter compares! Even the "Deep Blue Sponge Filters" & many others who simply stamp their name on the same Chinese knock offs that have infringed on the modular design patent of the Hydro Sponge Filter still do not have the same high capacity sponge.
Often these Chinese made knock offs simply change the color of the patented modular design to black or most recently green in attempts to get around the modular design patent!
The proof is in how many more rinsings it takes to clean an AAP/ATI Hydro Sponge Filter over ALL OTHERS due to the much higher capacity!

One inch diameter lift tube allows for high volume water flow and allows use of power head without adapters.
All sponges are 1" inner diameter (which may stretch to 1.25" inner diameter")

Raised off bottom, no dead space.

Heavier base.

The HydroSponge Filter provides both mechanical and biological filtration that generally excels over similar sized HOB Filters that generally are double the cost and much more expensive to keep!!!
Aerobic bacteria colonize the sponge providing a bacterial substrate to facilitate the nitrogen cycle.

In addition, the Hydro-Sponge traps waste particles mechanically cleaning the water without trapping the baby fish.

Excels as a small tank or bowl filter, especially for bettas which have fins that can get easily trapped in HOB or other filter intakes.

Excels as a breeding filter, as baby (fry) are not trapped by sponge filters and the Hydro Sponge #1 & #5 Stackable allows for additional filtration and hiding places for fry

Excels as a Discus filter, angelfish filter, hospital filter, or back up filter. Even as the Primary filter for larger aquariums (two #5 Hydro Sponge filters of #5 + stackable can easily handle a 75 gallon aquarium); also consider using Hydro Pond Filters in larger aquariums and sumps (see link in the left side bar))
Our maintenance companies have used these filters in Marine/ Reef aquariums (with live rock, generally in sumps ), with GREAT results!

MULTIPLE EXCLUSIVE SIZES & REPLACEMENT SPONGES:
Please note that the size tank given is the size (gallons) that we have used these filters UP TO, generally with more than one and is based on my real world experience using these filters.
Also note that we provide the size of each different SPONGE, the height of the entire sponge filter can be varied by cutting the 5 inch lift tube or adjusting the 1.75 inch base/step.
As an example, the COMPLETE #1 Sponge Filter with base/step, sponge, and uncut lift tube can be as high as 9 inches out of the box.

HYDRO SPONGE SET UP INSTRUCTIONS

Rinse and squeeze the sponge under water (our professional maintenance company recommends using used aquarium water in a separate container, then disposing of the water).
Then slip the sponge on the strainer.
Directions for use with a air stone (optional): Connect air stone to the bottom of the bull's eye, then connect bull's eye to the top of the strainer.
Then connect air line tubing to the bull’s eye on the sponge filter and the other end of the air line tubing to an air pump.

Suggestions for air pump applications:
Here is a diagram/picture showing how to connect an air diffuser to the bulls eye of a Hydro Sponge Filter. Also air line and lift tube connections.