Sponge pre-filters: Any gotchas?

[seangee]

A couple of months ago I attached a sponge filter to the intake my canister. The main reason was so I always had a cycled filter ready to go in case I needed to setup a hospital tank in a hurry.

I rinsed the sponges every week when I did my water changes and pretty much ignored the canister. Yesterday I felt bad that I had ignored the canister for 2 months so I cleaned it. Well I needn't have bothered. Is there any down side to reducing my filter cleaning routine to quarterly (or longer???) as the sponges are doing a great job of keeping the organics out?

 

[seangee]

Update after 6 months:
3 months after cleaning the canisters I took out the smaller of my canisters. I chose this one because the external heater is attached to the Fluval 406 which has larger diameter hoses. The filter was not dirty enough to warrant cleaning the Fluval.

So today after a full 6 months (and a bit because I was away last weekend) I cleaned the Fluval. When I squeezed the sponges the water did turn black but this was mostly tannin. The sponges were not at all blocked. There were some suspended organic particles in the water - but no more than I would normally have seen after a month. The ceramic media looked clean so got a rinse, as did the canister itself. The pipes were cleaner than I expected but this may be helped by the fact that I have been softening the water in this tank so there was zero limescale. I do clean the spray bar regularly and have been rinsing the pre-filter sponges twice a week.

I have never seen any nitrates above 10ppm and when I turned everything back on the flow looked to be exactly the same as before I cleaned the filter.

 

[The Lumpfish Guy]

Update after 6 months:
3 months after cleaning the canisters I took out the smaller of my canisters. I chose this one because the external heater is attached to the Fluval 406 which has larger diameter hoses. The filter was not dirty enough to warrant cleaning the Fluval.I have never seen any nitrates above 10ppm and when I turned everything back on the flow looked to be exactly the same as before I cleaned the filter.

I have intake sponges on all of my tanks filters, even the small ones. It prevents a lot of gunk getting into the filter "box" it'self and I think if it's leaving less gunk in the filter there is more surface area for bacteria to grow.
I don't really clean the filter media any less than I would do, just to keep on top of things. But I think it does help.

 

[Jeremy180]

Aquaclear 30 media bags have holes about 2-3 tenths of a millimeter, not sure if they would be the right size for an intake sock or not, if that would be a good substitute, or even if they are available in your area, but they would have been perfect me, had they been half as big as they are.

 

[The Lumpfish Guy]

I use something like this only costs a little and I find is really worth it.

https://www.amazon.co.uk/dp/B002LL32RY/?tag=

 

[AbbeysDad]

I have a sponge pre-filter on all my tanks (well except for the tanks that exclusively use sponge filters).
They are not only a fry saver, but also a food saver, and add a bit of extra life for the filter. For a staple food I use high quality tropical flakes, without the pre-filter sponge, a portion of each feeding would go in the filter. With the pre-filter sponge, they stick and the fish will pluck them off (no waste!). For some tanks (I have a very large coarse sponge pre-filter on the 37g) it also offers a potential platform for beneficial bacteria. Plus, I often see fish plucking away at this somewhat coarse pre-filter. They must be getting some sort of additional food from it (perhaps algae, infusoria or the like).
---
While on the (sponge) subject, my (3) Aquaclear filters in use are totally filled with sponge material as I find sponge not only to be excellent mechanical, but also excellent for biological filtration. Oh, there was a time I drank the koolaid and bought into the marketing hype of ceramic and pumice stone bio-medias. But their claims of increased surface area are short lived as all those micro pores quickly become clogged with detritus...which is why manufacturers recommend swapping portions out every 6 months or so. Oh, you can keep using the old stuff, but it becomes no better than if you used gravel in your filter!!!
These days, I just use bio-sponge material. It's inexpensive, cleans easily, and lasts forever and a day.

 

[NickAu]

Instead of media bags that look ugly try this.

They are like 2 bucks each.
https://www.ebay.com/itm/Stainless-...ter-Guard-Fish-Shrimp-12mm-16mm-/132529391796

 

[seangee]

I just use one of these on the intake pipe (no air pump) https://www.amazon.co.uk/gp/product/B01LZDXECV/?tag=. I have another one identical with an air pump ready to use for a QT or hospital tank if needed. Its sponges live in the back of my flex. So if I need to get a tank up and running instantly I can - and I don't need to lose my pre-filter to do so.

 

[AbbeysDad]

I almost forgot the 'gotcha'....if the pre-filter foam is too dense (like the fluval ones), it/they will need to be cleaned like every other day as they will plug and reduce/stop water flow.

 

[The Lumpfish Guy]

I almost forgot the 'gotcha'....if the pre-filter foam is too dense (like the fluval ones), it/they will need to be cleaned like every other day as they will plug and reduce/stop water flow.

I don't find this, I clean mine once a week as standard, and I will admit they do collect a load of stuff! but I have had them run for 5 weeks without cleaning and no effect on flow. That being said It will depend on a lot of things.

 

[AbbeysDad]

Yea, I switched to another sponge pre-filter that lasts a week easy - again, it all depends on the foam density.

 

[NickAu]

I used to use a prefilter sponge, I now put the sponge in my canister filters, I just got sick and tired of having to clean the sponges, I now use the stainless steel mesh much easier.