Q: Canister filter inlet options

[George Pontis]

All the canister filters that I have seen come with an inlet strainer that is
meant to be installed fairly deep in the water, and the filtered effluent returns
near the surface, preferably at the opposite end of the tank. Makes plenty of
sense in terms of water movement.

I was wondering what the pros and cons might be of skimming the surface, at least
partly, in the freshwater aquarium. One option might be to actually use a tank
with built-in overflow. Another would be one of the new gadgets from Eheim and
others that draw a mixture of surface and deep water.

I am assuming that the tank would be planted and injected with CO2.

Any thoughts, experiences to offer ?

[NetMax]

"George Pontis" > wrote in message
t...
> All the canister filters that I have seen come with an inlet strainer that
> is
> meant to be installed fairly deep in the water, and the filtered effluent
> returns
> near the surface, preferably at the opposite end of the tank. Makes plenty
> of
> sense in terms of water movement.
>
> I was wondering what the pros and cons might be of skimming the surface,
> at least
> partly, in the freshwater aquarium. One option might be to actually use a
> tank
> with built-in overflow. Another would be one of the new gadgets from Eheim
> and
> others that draw a mixture of surface and deep water.
>
> I am assuming that the tank would be planted and injected with CO2.
>
> Any thoughts, experiences to offer ?


There isn't the same necessity of skimming freshwater tanks as there is with
sal****er. It's almost a cosmetic issue with freshwater (removing the
protein layer) though it does improve equalizing CO2 and O2 levels (which is
not necessarily a good thing with CO2 charged systems as it drives off the
excess CO2 slightly faster than would normally occur). While skimmers might
seem at cross-purposes with CO2 injection, in some applications which have a
lot of CO2 added, then the amount lost might not be significant.

Mechanically, skimmers can be a PITA. Carefully designed, installed and
adjusted, they work beautifully - then your water level changes and slime &
algae coat everything. Here is where some skimmers are better than others.
ymmv

Overflows can work great, however in any planted tank, there is an increased
risk of blockage as leaves break away and move in the turbulence towards the
intake. I like designs where a blocked intake does not cause the tank to
overflow (obviously ;~), but this generally requires some margin in water
levels (you can't ever completely fill the tank, nullifying your safety
margin). All in all, I prefer the simplest and most robust designs possible
with planted tanks, so I prefer to only use overflows with water change
systems (because you are viewing the operation), and not in normal
filtration paths. It is possible to do, by keeping your return flow rate
modest, oversize your intake grill and test worst case scenarios. Wet/dry
sump systems address these issues all the time.

ps: overflows depending on design *can* be noisy, ymmv

that was my usual wordy 2 cents
--
www.NetMax.tk

[George Pontis]

In article >, says...
> "George Pontis" > wrote in message
> t...
> > All the canister filters that I have seen come with an inlet strainer that
> > is
> > meant to be installed fairly deep in the water, and the filtered effluent
> > returns
> > near the surface, preferably at the opposite end of the tank. Makes plenty
> > of
> > sense in terms of water movement.
> >
> > I was wondering what the pros and cons might be of skimming the surface,
> > at least
> > partly, in the freshwater aquarium. One option might be to actually use a
> > tank
> > with built-in overflow. Another would be one of the new gadgets from Eheim
> > and
> > others that draw a mixture of surface and deep water.
> >
> > I am assuming that the tank would be planted and injected with CO2.
> >
> > Any thoughts, experiences to offer ?
>
>
> There isn't the same necessity of skimming freshwater tanks as there is with
> sal****er. It's almost a cosmetic issue with freshwater (removing the
> protein layer) though it does improve equalizing CO2 and O2 levels (which is
> not necessarily a good thing with CO2 charged systems as it drives off the
> excess CO2 slightly faster than would normally occur). While skimmers might
> seem at cross-purposes with CO2 injection, in some applications which have a
> lot of CO2 added, then the amount lost might not be significant.
>
> Mechanically, skimmers can be a PITA. Carefully designed, installed and
> adjusted, they work beautifully - then your water level changes and slime &
> algae coat everything. Here is where some skimmers are better than others.
> ymmv

Thanks for the well-considered comments. Your reminder of the problems of skimmers
does have a wall of dulling my enthusiasm for installing another, especially if
not necessary. Last night, and after posting, I went to do a water change on this
tank and was somewhat surprised to see a lof of algae growing in a film on the
surface. I guess that's the power of two 96W PC lights...