Are sponges needed in filtration?

[Dhub]

I've attached a crude drawing that shows the sponge in my overflow, sump and on the return pump. Are the sponges needed? If so how often should they be cleaned? If they arent needed should they be removed altogether? Can this be the reason why my nitrates hover around 25 no matter how many water changes I do.

 

[Corigan]

I don't know if you need them or not as the drawing isn't very clear for me, but I removed all sponges from my setup as they are nitrate factories. If you have to leave them in they would need to be cleaned every week atleast, much like filter socks.

 

[wicked demon]

I wouldn't keep any sponges. Nitrates are due to poor nutrient export.

 

[Dhub]

Forgive me while the new wears off... but what does "Nitrates are due to poor nutrient export." mean?

Thanks

 

[Mariner]

Sponges can definitely be nitrate factories. Rinsing them frequently can prevent this. But they also can serve an important function in reducing microbubbles and noise at certain locations in your system; if you don't need them for these reasons, I'd ditch 'em all together.
FWIW,
Mariner

 

[Troylee]

I would lose the sponges for all the reasons above...

 

[AZDesertRat]

I don't use any sponges or filter socks in any of my systems.

 

[stunreefer]

Just to clarify, people always refer to sponges as "Nitrate Factories", as if they just randomly release Nitrate into your system... not true. Sponges are excellent media to harbor beneficial bacteria, which run the nitrogen cycle, so they're constantly breaking down the nutrients in the cycle: ammonia ---> nitrite ---> nitrate. This is one means where nitrate comes from, along with the fact that sponges can trap detrius and uneaten foods, and if left there, will be broken down into nitrate. If you don't have a sponge, they might just be blown around down into the sump (or elsewhere) but if not consumed will also eventually break down into nitrate as well.

Bottom line is if you clean your sponge(s) frequently, they're great at exporting nutrients and maintaining a "cleaner" system.

Per your drawing there, I would remove the one on your return pump (no one ever gets around to cleaning those). You could try removing the one in your overflow, but it might cause noises since it's HOB, and you could try removing the one in your sump if there's not a microbubble issue. Personally I would leave the one in the overflow and clean freqeuntly, unless you run a filter sock, and remove the rest.

It's important to understand how and why things work, then decide for yourself, rather than buying into comments like, "Don't do it, it's a nitrate factory".

 

[AZDesertRat]

I would also add, rinse them out on saltwater to preserve the bacteria. Fresh water, especially chlorinated tap water will kill the beneficial bacteria if used to rinse. Way back when I did still use sponges I would use a little of the old water change water to rinse my sponges before tossing it.

 

[Mariner]

Well, since I was the one who used the term "nitrate factory" I think I should clarify that what I meant by that (and I think what most other knowledgable reefers mean when they use the term) is exactly what stunreefer described in his first paragraph. Sponges are excellent at harboring the beneficial bacteria needed to complete the nitrogen cycle.
I certainly don't use the term nitrate factory to indicate that sponges just randomly release nitrate into your aquarium. I don't know anyone else who uses it that way, and I frankly I resent the smugness of the characterization.
Mariner

 

[stunreefer]

I certainly don't use the term nitrate factory to indicate that sponges just randomly release nitrate into your aquarium.

I wasn't thinking that you did, I knew exactly what you meant

However I see day in and day out people on forums "parrot" things they read and have no idea how/why things work or don't work yet take it with no grains of salt, then the info is passed on and on and on. Sponges is one thing that is consistantly brought up as being "bad". You see the same kind of thing when people mention crushed coral, etc., etc.

I was merely pointing out why they're referred to as such and how it can be prevented. No harm intended Mariner.

 

[SDguy]

Well thank goodness I read through the whole thread before I started talking about all the sponge I have growing on my live rock and how I think it really helps the "filtration" in the tank... :beat_brick:

 

[Dhub]

Thanks all for the info. I've never cleaned any of the sponges since the tank was setup - LFS actually told me not - beneficial bacteria.

I'm going to remove the sump sponge and the return sponge to see if this helps with always high nitrate level. Again, I appreciate all the advice and help.

 

[SDguy]

Thanks all for the info. I've never cleaned any of the sponges since the tank was setup - LFS actually told me not - beneficial bacteria.

I think they just meant don't wash it under the faucet. Simply rinse it in tank water (ie during a water change, in the old water that you are going to discard anyways) and you won't bother the bacteria. This is the school of thought when you WANT to grow your bacteria in your filter.