"Peter in New Zealand" wrote in message
news

I have a medium sized tank which is very underloaded with just three
fish. It's been running like this for about a month now and everything
seems to have settled down and got comfortable. I started out with a
really cheap internal filter that blew lots of bubbles but didn't seem
to do a whole lot of filtering. When I pulled it to bits to see how it
worked I just couldn't see how it was expected to do anything but the
most primitive filtering. I guess you get what you pay for, and it was
cheap. Recently I installed a Hagen Stingray internal filter. I keep it
running all the time and the filtering and circulation it provides is
wonderful. My question is this - does increasing the filtering increase
the practical capacity of the tank? In others words can I carry more
fish comfortably? Obviously there would be a practical limit to all
this, but within reasonable limits would this be a correct assumption?
The Hagen has plastic foam, for biological filtering I presume when the
bacteria get established, and two activated carbon cartridges. Thanks
for any comments - I really am a little new to all this.
--
Peter in New Zealand.
Pull the plug out to reply.
You would need to specify how many gallons your medium tank is for more
specific advice, but if I recall the design of the Hagen Stingray, I
don't think that would keep up with only one Jar Jar Binks, and I don't
know what your other 2 fish are. If all three are goldfish, then your
aquarium is between 30 and 60g and generally speaking, will need more
than average filtration (goldfish!).
Generally, increasing the filtration (by adding more filters) will
increase the tank's capacity, however whether this is a practical
increase depends on what the next constraint is. For example, in a tall
narrow tank, an early constraint is the re-oxygenation of the water.
Extra filtration might help (extra turbulence at the surface), but you
would get into trouble faster during a power failure, so might not be a
practical increase.
Another example is substituting the only filter with a much larger filter
(on any tank). Any single mechanical failure would more rapidly
adversely affect the fish if you had added more because of the larger
filter.
A last example is that adding more fish load creates more waste, which
extra filtering will help with but only to a point. You would need to
also increase the other maintenance (gravel vacuuming, water changes) to
address what the filter cannot help with (solid waste accumulation and
dissolving back into the water).
As a general rule (which works nicely with goldfish), if you need
filtration for a 40g, then use two filters, each rated for a 30g and
clean them on an alternating schedule.
--
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