Filters and stocking levels

[Arfie]

Hi,

Sorry to ask what's probably a stupid question, but rather ask a stupid question than make stupid mistakes, eh?

Is the recommendation for the number of fish in a tank, based on the ability of the filtering system to clean away the waste?

The reason I ask is that I've just (a few weeks ago) got myself a Juwel Reckord 60, 10 Gallon (UK) tank with a built in Juwel 3 stage filter, the guy at my LFS claims not to like these sytems and suggested an undergravel filter, which after consideration I decided to do for the smal extra cost that is was. Now, on his suggestion I have had both filters running together which seems to the untrained eye (namely mine) to work brilliantly as when I set up the tank all the crap off the gravel clouded the water and it took about 3 hours to get it crystal clear, even the LFS were surprised as they expected it to be 24 hours at least.

So if the bacteria is resident in the built in filter AND in the undergravel filter, I must have nearly twice the normal number of bacteria present as in a normal tank, or am I misunderstanding the process?

If they do add up and increase the ability to remove ammonia & nitrite, does this in theory allow the overstocking of fish? subject obviously to them still having enough space?

Cheers
Arfie

 

[tstenback]

It doesn't ALLOW overstocking but it would certainly help if you were overstocked. It also does not give you twice the bacterial colony just more space for the bacteria to grow. The bacteria generally grows to consume the available ammonia. so you can only have the amoount of bacteria that the ammonia will support. hope that made some sense

 

[Arfie]

Thanks Tstenback,

Poorly stated on my part, I meant twice the capacity for the bacteria. (you'd have thought being English I'd have a better grasp of the language than I sometimes do )

I do understand that they will not be present unless there is sufficient Ammonia for them to live off.

So there is the potential capacity for removing more ammonia/nitrite than just the one filter method, if there's enough fish to provide the ammonia.

So in theory I could stock higher than recommended levels of fish?

Not intending on doing so you understand, I just like to know. I wish to keep both filter systems as a redundancy measure (belt and Braces approach) in case one fails.

I'll be asking many more silly questions over the next few days/weeks

Cheers
Arfie

 

[clutterydrawer]

It would probably allow for a bit of careful overstocking but a very important thing to consider is the surface area of the tank. Fish use oxygen which is disloved in the water. As the oxygen enters the water from the surface, the bigger the surface area, the more fish it can support. If there are too many fish relative to surface area they suffocate so be careful.

 

[Arfie]

Thanks Clutterydrawer,

I knew there'd be more than one reason why the limits are there.

As I said, not looking to overstock just wondered if you could, just the way my mind works I'm afraid.

Arfie

 

[clutterydrawer]

It's the way everyone's mind works I think. I always want more fish than I can have.

But I think as long as you don't overstock according to surface area, I think extra filtration will allow you to keep more than you would without the extra filtration. _but_ I also heard that undergravel filters can cause problems in that they trap all the dirt under the gravel, so they're hard to clean, which pollutes the tank. dilemmas!