throttling a canister filter

[jaiden]

A friend of mine has a canister filter which flows too much for his tank (ok, wrong forum I guess since it's [acronym:6a083114c3="Freshwater"]FW[/acronym:6a083114c3]). He asked me if it can be throttled with a rheostat (a light switch dimmer).

I had to admit I have no idea...

anyone?

[Atari]

I would think something like that would reduce the life of the pump.. that's why it's important to match output before buying.

Even the fluvals with the built-in mechanism for reducing flow tend to last longer when you leave it on full.

[RocketSeason]

you can put a valve in the return hose and close it down a bit, but like atari said, your ruining your canister filter that way.

how about a new, smaller canister filter???? or a nice big [acronym:418f9c6463="Hang On Back"]HOB[/acronym:418f9c6463] filter?

[grimlock3000]

What size tank is it and what type of canister is it? It might not be an issue where the canister has too much power, he could just be distributing the water poorly.

[jaiden]

I haven't seen it, but trust me, it's too big.. it sucks the poor fish down to the bottom when it's on...

I'd guess it's a 200+[acronym:ef2b8a037d="Gallons per hour"]gph[/acronym:ef2b8a037d] filter on a 3-4 [acronym:ef2b8a037d="Gallon"]gal[/acronym:ef2b8a037d] tank

it's a split terrarium with dirt or something on one side and a beta on the other.

I know, I know. wrong forum.

He already has the filter though, and doesn't want to get rid of it.

[grimlock3000]

I'd guess it's a 200+[acronym:a199a46ab6="Gallons per hour"]gph[/acronym:a199a46ab6] filter on a 3-4 [acronym:a199a46ab6="Gallon"]gal[/acronym:a199a46ab6] tank

He already has the filter though, and doesn't want to get rid of it.

If this is the case, he just needs to not use it. Or buy a bigger tank. It does not matter how much he wants to use it, if it is simply not approriate for the tank its not going to work.

Back to your original question, you can not slow down a canister (or other aquarium filter) by the use of something like a rheostat. You can block the water flow with shut off valves and such, however like previously mentioned, those are not a good idea.

[jaiden]

pardon me if you don't want to explain your point, but I don't get it...

why wouldn't it work? isn't the motor in a filter basically the same thing as the motor in say, a window box fan? aren't these slowed by a dimmer switch? seems like the pump would turn slower with less voltage.

or is there just something about the impeller that only works at a certain speed.....? or am I missing something entirely (does it have something to do with 60hz [acronym:c73759d0c1="Activated Carbon"]AC[/acronym:c73759d0c1] current?)

[MattP725]

They are not speaking of it that way... they are saying if you restricted flow using a valve. The back pressure against the pump working at full speed would cause extra work load eventually overloading the pump... what you are saying is cutting the voltage which also is not a good idea... fans use a magnetic motor which is ok with less of a voltage because there really aren't any real gears or anything that are stressed. I don't know the mechanics of a canister filter motor but just cutting voltage on any old electronic item is def not a good idea. Infact he may fry the motor doing that. If I were him and were insistant on using it I would get a foam prefilter guard to put around the intake... that way the fish couldn't get close enough to get stuck to the guard but most particles could still penetrate or atleast get stuck on the prefilter.

[RocketSeason]

Originally Posted by jaiden

I'd guess it's a 200+[acronym:a470fc5c08="Gallons per hour"]gph[/acronym:a470fc5c08] filter on a 3-4 [acronym:a470fc5c08="Gallon"]gal[/acronym:a470fc5c08] tank

talk about overkill!!!

for that sort of situation he is best off getting a small sponge filter. (about 10-15 bucks.)

Otherwise he will just be killing everything he puts in there.

save the canister filter for another tank. a 200 [acronym:a470fc5c08="Gallons per hour"]gph[/acronym:a470fc5c08] filter would be good for a 75 gallon [acronym:a470fc5c08="Freshwater"]FW[/acronym:a470fc5c08] tank.

[grimlock3000]

or is there just something about the impeller that only works at a certain speed.....? or am I missing something entirely (does it have something to do with 60hz [acronym:6108be21ce="Activated Carbon"]AC[/acronym:6108be21ce] current?)

Most motors used in aquariums are controllerless, their rotation is based of the 60Hz [acronym:6108be21ce="Activated Carbon"]AC[/acronym:6108be21ce] current. A while back I tested my equipment when plugged into a cheap UPS unit designed for a computer. None of the filters worked right, they all just clicked a lot. This is because the output from the UPS was a 60Hz squarewave, and the output from the wall was a 60Hz sinewave.

Fans used in computers are [acronym:6108be21ce="Direct current"]DC[/acronym:6108be21ce] fans, not [acronym:6108be21ce="Activated Carbon"]AC[/acronym:6108be21ce] fans. Not sure on large box fans, but at that point you are comparing very different technology.

When I push down the gas pedal in my car, the engine goes faster. Can I use a gas pedal on my canister filter? :P