Sponge or not sponge?

[mlovelace]

I want to thank everyone again for the constant source of information on this site! I have truly learned a ton, hopefully prevented some headaches, and already saved some cash!

The current used set-up I purchased has a sump with a sponge in the bottom, that the water travels through prior to hitting the area with the return pump (Mag 7). I am curious does anyone else use a sponge as well or do most of you trash them? I have read several articles that they are notorious for helping build up the nitrates?

If you do have them, how often do you change or clean. I have looked at my LPS and LFS and cannot find the same size sponge. The size is 9x2, but the person before me may have purchased bigger and cut it down? I can't tell what kind of sump it is either. The one thing I am not a big fan of is the overflow area the water comes into. It is tall/ thin and enclosed tightly. I was wanting to add a filter sock, but there is no way.

Does anyone know of a website with this size sponge or bigger?

I believe my sump is a megaflow #2

Thank you, Mike

[gregony]

Hardware stores like Lowe's or Home Depot sell sponges of every size imagineable. Stay away from ones that claim to be mildew resistant or the like as they use chemicals to accomplish this, that will wipe out your tank if you use them. I bought a sponge to cure the tile work I did in my bathroom that was 100% natural (because you don't want any residue from mystery crap when you're applying sealant) and roughly the size you say you need. I can't remember if it was Lowe's or Home Depot that I got it from. I know it was about 6 bucks. Keep the sponge clean and it shouldn't be a problem. If you think it will be a nitrate problem, try before and after. Run your tank for a while with it and keep track of the nitrates (which you should be doing anyway). Then remove it and see if there is improvement. My guess is that nitrates will be unaffected (provided you are keeping the sponge clean).
Also, while you're there, you may find something to solve the inlet dilemma you have.

[ToddTT]

I had one in my overflow, a little larger than a soup can. (Replaced with a Durso pipe a few days ago.)

Another in my sump, 1 inch thick, and the size of a dinner plate.

I used to clean the overflow sponge 2 or 3 times a month. It would get dirty quick.

I clean the sump filter less frequently. I think I'm going to start giving it a good rinse when I do water changes, using the water I siphon out. This is supposed to be much friendlier to the good bacteria.

These two sponge filters are over 10 years old now!

The last time I read my nitrates they were about 10-15 ppm, for my FOWLR 75 gallon tank.

I'd say rinse yours out, and put it back in.

What are your current nitrate readings?

Is the sponge getting dirty? If you were to remove it, where would this stuff go?

[gregony]

IMO every cubic inch of filtration that you can get into your system helps to some degree. Whether or not the sponge does six dollars worth of helping, only you can know.

[mlovelace]

Thank you guys for the info.

I am at the tail end of my cycling stage, so I don't think it would be a true test of my nitrates right now. I checked them last Saturday and they had dropped back down to 0. I am trying to purchase things in advance and get a feel for what others are doing. The problem I have noticed with the sponge is I have to keep the water level above the sponge, to keep the return pump from sucking air. I am wondering how much it is really helping? If I keep the water level down to where all the water had to go through the sponge, I would be adding a small amount of water every day. I could buy a much larger sponge (taller), so that all water must pass through it? I believe the actual name of the blue sponge is a bubble diffuser?

If I am understanding everyone correctly, I should use an all "natural sponge"? The bubble diffuser is not at a less porous amount is it?

There is also a sponge filter over my return pump (mag 7) to help some. I ordered an extra one of those to help swap out and keep it clean. Does anyone ever put a sponge or filter floss in the top of the overflow (where the return inlet and overflow outlet is located)?

Thank you, Mike

[ToddTT]

There is also a sponge filter over my return pump (mag 7) to help some. I ordered an extra one of those to help swap out and keep it clean.

Pop it off, rinse in saltwater, and put back in place. Plenty of helpful bacteria on that sponge.