Floating Scrubbies

I want to add a lot more bio media to my tank but I already have one large canister filter and due to leak and maintenance issues, I don't want to add another canister and I don't have wall space for HOBs so I've got this strange idea...can I just float a bunch of pot scrubbies on the surface of the tank?

Aside from aesthetics, would this actually work to help filtration? Since the water is moving, would the scrubbies have enough oxygen? Would they help to move water around the surface to oxygenate the tank or would they hinder it? I understand that only the bottom portion of the scrubbies touching the water would have bacteria but would that be better than not having it at all?

My fishes eat sinking pellets so they never come to the surface so I'm wondering if I can utilize that room for scrubbies. I have a heavily stocked tank and never quite know how much bio media I need and have read differing opinions on the topic. Some say bacteria is a ratio to the "amount of fish kept in the tank" so the more you add the better in heavily stocked tanks. Others say bacteria is a ratio to the "size of the surface area of the tank" so it doesn't matter how much bio media is added, the size of the tank determines the amount of bacteria it can support. Does anybody know for sure?

 

Maybe before you do that get sponge filters???

 

Do you mean prefilters for my canister? I have one and also have a sponge attached to a power head. But I thought scrubbies provide more surface area for bacteria than sponges?

 

If you're not getting ammonia and nitrite spikes, you're fine.

 

Everything seems good for 3 days after a water change but things get a little less stable afterwards and the water is visibly less clear. Purigen seems to help water clarity but it turns brown after 2 weeks so I'd like to increase the bio capacity of the tank if I can.

 

What is in your cannister filter already? Often times we can add other media in the cannister itself, and increase capacity by quite a lot.

Water clarity could also be helped by a water polishing action.

Both statements about the bacteria population are true.

To see how it is both true, think of it like this. You have 1 fish. His waste can feed 10 bacteria. Your tank can hold 20 bacteria.

Your bacteria will not grow beyond 10 , since there isn't enough food for them (fish waste). You add another identical fish, now you can support 20 bacteria, and this is also the amount that the tank can support.

You add another third identical fish. These 3 fish could feed 30 bacteria, but you only have enough space for 20.

So to get up to 30 in the same tank, you can add more surface area via the media, as an example.

So you do need fish population (their waste) to support more BB. This is the idea that some people say, the number of fish determines the BB size.

The BB grow all over the tank's surface and other object surfaces but more of them are in the filter media. This is the idea that some people say, the tank will be the limiting factor (they're not wrong but the filter media is most important). That's why the filter media is the most important to preserve across water changes. You can take out rocks and plants and wipe down the tank surfaces to get rid of algae, but if the BB in the filter are safe, then the tank resumes its operations after the maintenance.

To make use of that top space of the tank, I think you could make a horizontal DIY bottle filter. Most examples are positioning the bottle vertically, but I think you could achieve a similar result by positioning the bottle horizontally. Make the escape holes along the side of the bottle (rather than at one end like the vertical examples), and as the air works its way through the length of the bottle, it gets water and oxygen movement through the bottle.

 

Thanks so much, purslanegarden! That was very helpful.

I have an Eheim Pro 4 600 and the media it came with - which is a coarse prefilter sponge, filter plus pad, substrat pro, bio mech, and mech pro. Here's what they look like starting at 2:17 into the video:

I tried a horizontal DIY bottle filter but couldn't get the physics to work right. The bottles won't hold together well enough to support the powerful stream of water flowing from one side to the next but I'll continue to test and learn. Which makes me wonder, how important is it to have oxygen flowing through all the scrubbies? For ex. if I have 10 scrubbies lined up submerged near the surface of the water and a powerhead is blowing water/air bubbles against it on one side by the time it reaches the 7th scrubby, the power of the water/air stream is lost and so the 8-10th scrubby is just sitting beyond the tail of the stream. Would they still be able to hold BB but not as well as the first 7 scrubbies or would they not really do much?

 

Sorry if youve already fixed the problem, but by sponge filters I meant as in the air driven ones you hook up to an air pump.

 

Thanks, Kettlekorn13! I have one of these but found the bubbling sounds they made a bit loud because I already have a couple of air pumps (attached to air stones) going. Do you know of a way to dampen the bubbling noise?

As a side note, I've always wondered what the clear plastic tube on the top was for. Does anybody know?

 

Thanks, Kettlekorn13! I have one of these but found the bubbling sounds they made a bit loud because I already have a couple of air pumps (attached to air stones) going. Do you know of a way to dampen the bubbling noise?

As a side note, I've always wondered what the clear plastic tube on the top was for. Does anybody know?

Attaching a finer air stone can reduce the bubbling sounds. The clear tube is to increase the amount of suction the air bubbles produce.

 

I'll try that. Thanks, tocandesu!

Although a sponge filter won't increase my bio media that much, at least it'll help with the mechanical part.

 

I'll try that. Thanks, tocandesu!

Although a sponge filter won't increase my bio media that much, at least it'll help with the mechanical part.

Actually, a sponge filter is more biological than mechanical.

 

Yes. Sorry, just to clarify, they do provide biological filtration, it’s just that my sponges dirty quite quickly so they’ve worked more as mechanical filtration for me because of how frequently I clean them.