Sponge Filters

[aggie_67]

After seeing several pictures on this forum of hydro sponges in operation with out using the riser tube, I had to make a comment.

Hydro sponges work on the "air lift" principle, a very old engineering principle of moving water. The air bubbles rising in the outlet tube is what does the pumping. No tube, minimun flow through the filter.

[RyanH]

Actually I've removed the tubes on many of my Hydro Sponges and they still have tons of waste in them when I clean them out.

[Lance_Krueger]

aggie67,
You're right. That is if you just stick your airhose onto the nipple at the top of the sponge (where the clear riser tube attaches too), then yeah, you'll get little effect. So if that's all you do, then you really need the riser tube. Something I do is attach another 3-4" piece of airline tubing to the nipple on the opposite side where the airline attaches to your pump, and run that into the bottom of the core of the sponge. This way, you get air lift all the way along the length of the sponge. I even double stack some of my Hydrosponges, and get even more lift that way. And if I've got enough height in either case, I always have the airlift pipe to give more suction through the sponge.
Actually, I got some sponge filters from Jeff at Discus Farm that were made over in Asia. They are made so there is a built-in air tube that goes to the bottom of the sponge so you don't have to make one yourself out of a piece of air hose. You just attach it to the top nipple, and the air starts at the very bottom of the base of the sponge filter. They have a clear air riser tube too, which I have on all of mine. Plus, they're made of heavier plastic than the Hydrosponges, so it seems like they should last longer. I bought all Jeff had, so don't know if he has any more. Don't know name either since I had him take them out of the boxes to put around the fish I ordered from him.
Lance Krueger
Lance Krueger

[Fishin dude]

I threw all those muffler pipes away....dirt collectors and always in the way.
Maybe a little more suction(using tubes) with less air....so I turn the air up