I had this topic posted in the last forum but since all the old posts have been lost I figured I would post it again. I have spent many years trying different sponge filters for my breeding room and decided I would share my experience on these different sponge filters with the rest of you all.
We will start off with the first filter I purchased for my breeding tanks. Although it is not really a sponge filter at all the box filter is a little more versatile. I still use them in my tanks now with some crushed coral in the bottom to help buffer the water. On average they cost around $3.00-$4.00 a piece.
The next filter is the triangular foam filter I purchased online. After opening them up I immediately knew the pore size would not be optimal. I gave a few of them a try anyway and sure enough my initial thoughts were right. Not only do they clog very easily but getting them to sink in the tank was a hassle within itself. In the end you get what you pay for. At a cost of around $2.00 a piece for twenty of them they are definetely the cheapest foam filters you will find. I would not reccomend these to anyone.
Now we move on to the regular ATI Hydro Sponge. These were the first line of sponge filters followed by the Pro line. The pore size is not optimal and they tend to get clogged easily. They do however work fine as I have used these for a few years in my fish room. You must be willing to squeeze them out about once or twice a month and replace the sponge once or twice a year. The smallest size (mini) is around $4.00 and works for a tank under ten gallons. The next size up is the #1 at a cost of around $5.00. This is the one I used and is also the one in the picture. They have three other sizes available #3, #4, #5. The best place I have found for these is. http://www.kensfish.com/spongefilterlinks.html
Now we move on to the ATI Pro line. These in my opinion have to be one of the best sponge filters around. Unlike the regular ATI sponge filters these have optimal pore size and they do not degrade over time. If you are currently using the regular ATI sponge filters all you have to do is buy the replacement pro sponges and slap them on. They however do not make a Pro size #1 so to fix this all you have to do is buy the Pro size #3 and cut it in half. They range in price from $6.00 to $8.00 and can also be found at http://www.kensfish.com/spongefilterlinks.html
Lastly we have the DIY filter. These are some of the most versatile filters as you can buy the foam blocks in bulk and cut them to whatever size you need. Attach them to a slate tile and cut a hole for an uplift piece of pvc, or whatever you want to use, and you have a homemade filter for any size tank. Depending on what size you make them they will cost you between $4.00 to $8.00 on average. You usually find them in either 10ppi or 30ppi, I prefer the 30 ppi size. Here are a couple of places to find the foam in bulk blocks to cut to your own size http://www.swisstropicals.com/Poret%2 ... r%20Foam%20Pricelist.html http://plecocaves.com/Poret.htm http://www.lagunakoi.com/subcat139.html