Too much filter for my tank?

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jd8521

Aquarium Advice Apprentice
Joined
Oct 19, 2009
Messages
12
My old HOB filter died last night. I ran out and grabbed a filter for a 40g tank. Is this too much filter for my 29g tall? I have it set on high flow and when I feed I drop it to low to make sure the fishys get some food.
 
Well, from what I've heard about aquarium filtration, its best to get a filter atleast 10 gallons OVER your tank size.
sounds like your perfectly fine!
 
Well, from what I've heard about aquarium filtration, its best to get a filter atleast 10 gallons OVER your tank size.
sounds like your perfectly fine!
most filters you can cut in half or more. they over rate their filters all the time. i run a AC 70 on my 29 and think its under filtered.
 
actually, AC filters measured with an inline flow meter to flow just about what theyre rated (give or take a couple of GPH depending on the individual impeller).

i have a tank running 60x turnover/hr (thats 1 turnover a minute for my math friends) and its running perfectly.
i also have a 40g with a 450 gph sump and 2x 500gph HOB, and there is no added stress to the inhabitants.
 
but does that include the media? even if it did that would be new unclogged media run it in a tank a day or two and it sure doesnt have the same flow.
 
if your tank is filthy enough to dramatically clog your media in 2 days, then the flow rate of your filter is the least of your worries.

with regular cleaning (as directed by the manufacturer, as well as fellow aquaria enthusiasts) you will not have to worry too much about reduced flow due to debris build up in the filter. though it will reduce it as you suggested, it should not be enough to make a noticeable difference.
 
never did flow meters on mine but ill give you that.though i do run floss in mine which you can see the slow down with or with out it. i didnt say you can cut gph they claim but the tank size.

i use what i know. for example aquaclear 20 they say is for a 20 gallon tank with 126gph. i would never run a tank with just one of those on there. not only are you running low turn over rate but small area for the media. bigger filters with higher turn over rates tend to also have larger media area.
 
i think youre confusing media volume with available surface area for bacterial colonization. with a good quality bio-media (such as the bio max pellets the AC20 come with) you get a ton more surface area than other media like ceramic rings (i believe its 6-10x. i dont remember the exact amount, id have to look it up). so even though the volume of the media basket doesnt look like much, there is a lot more room for microscopic bacteria than you can see.

also with a properly stocked 20g tank, the 6x turnover of the AC20 is more than enough. however, i agree with more filtration = BETTER. smallest filter i run on a 20g is an AC50.
 
Gallons per hour alone isn't the proper measurement for a filters performance it's the quality of the filtration that matters. I would chose a filter that has as close as possible to 0 bypass as possible over GPH.
 
That size filter is fine on your tank. The gph is tested without media in the filters, when media is added, depending on how much, it will sow the gph of the filter.

If the outflow is to strong for your fish, you can always fix a spnge over the outflow to distribute the water more as it flows back into the tank.
 
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