Most aquarium filters now use a motor to force water through some kind of filter pad which must be replaced at intervals. However, before there were reliably sealed electric motors, most home aquariums moved water using the "airlift" principle, in which a rising column of bubbles pulled water through the filtering material. This is an elegant and just about failsafe method. Debris in the tank cannot ever jam the external air pump which feeds the filter, and if electricity is interrupted, the filter cannot lose siphon, it simply starts bubbling again when power is restored to the air pump. Many fish love to play in the rising stream of bubbles.
Hydro Sponge filters, first marketed in the 1990's, are a more recent application of the airlift. Hydro Sponge III is intended for aquariums up to 30 gallons. Made of dense, strong plastic with a weighted base which holds the sponge up away from the aquarium bottom, they dismantle easily for cleaning of the sponge. The pores within the sponge provides an enormous surface area for colonization by beneficial bacteria providing very thorough biological filtration. They can be powered by an air pump with or without an airstone (using an airstone will give finer bubbles and make less noise), or with an electric powerhead for those with larger tanks or who simply feel the need for more energetic water movement.
It is difficult to imagine such a simple device working well. Surprisingly, they are excellent, and can be used as the only filter in the tank for many applications. I've used them on tanks sized from 10 gallons up to 75 gallons, always with good results. The local fish store where I shop has an expensive trickle filter for their dozens of tanks, and every single freshwater tank also has a Hyrdo Sponge or similar sponge filter as well. Apparantly the sponge is doing something which the trickle filter doesn't?
Maintainence is as simple as the filter. When you perform your periodic aquarium water change, (20% every week) save some of the old water in a bucket. Separate the top and bottom parts of the filter and remove the sponge from the tank. Squeeze it out in the bucket. See all the stuff which the sponge removed from the water? Reinstall the sponge and refill your tank. Go have dinner with the money you saved not purchasing replacement filter cartridges.
In sum, a clever and elegantly simple device which works very well.
I ordered 2 of these "Pro" filters and was disappointed to find out they are the regular Hydro Sponge and not the Pro Version. Although the seller describes this as:
"The Pro line is constructed of reticulated foam which doubles its efficiency."
This is not the case. I notified the seller and was told the title and description were a mistake and would be changed. Now after 4-6 weeks, it's still the same... Misleading description.
The seller did refund my money, but here I am searching for the PRO version again and this is still listed incorrectly.
I did give the item 5 stars.... All Hydro Sponge filters rate this, IMO.
Jim
Buy Hydro III Sponge Pro Filter - Up to 40 gallons Now
I have a smaller version of this filter in my 10 gallon freshwater aquarium (female betta and 6 harlequin rasboras). I decided to add this size hydro sponge filter to my 30 gallon goldfish aquarium, not only for the extra mechanical and biological filtration, but also for the extra oxygenation from the bubbles bursting in the water.
Goldfish create heavy bio-loads, and you can't get enough filtration for them. Sponge filters are remarkably simple to use and maintain in the 10 years I've been keeping fish, I haven't had a hydro sponge pro sponge wear out.
I rinse in used tank water (I dip out some tank water before I start to siphon), and squeeze the sponge out until the rinse water from the sponge runs clean. As long as you don't use the sponge as a scrubber, there shouldn't be a replacement problem with the reticulated foam on the pro version of this filter for quite some time.
Read Best Reviews of Hydro III Sponge Pro Filter - Up to 40 gallons Here
I first heard about this system on a planted aquarium discussion board.
After trying it for myself, I am very pleased with the results. Read the previous reviews for details but try it for yourself and you wont be disappointed. Of course the best place to find it is Amazon!
Want Hydro III Sponge Pro Filter - Up to 40 gallons Discount?
You'll hardly--if ever--see these filters carried in the big box pet stores. Why? Simple: they're not money-makers. The initial cost is low, and there's no need to keep going back to the store to purchase replacement media. Simply give them a good rinse (I always do this with any new piece of equipment), connect them to your air pump, and you're ready to roll. The rising air pulls water through the sponge, trapping waste. The sponge provides a great place for beneficial bacteria to grow (a VITAL part of your filtration), and it aerates the water while you're at it. In some tanks, sponge filters alone could provide adequate filtration. I generally use these to supplement my HOB power filters (Aquaclears).
Maintenance is a piece of cake. Simple rinse out the sponge every few weeks or so (in a bucket of water from the aquarium, so you don't kill the bacteria). As with adding any filter to a tank, always make sure you're taking steps to establish and maintain your biological filter (bacteria).
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I put a little of this in the pond a week before catching the fish to clean it, then I use it after I add water to conditiont he water and further help with getting the fish coat strong. I haven't had any issues with it.
