Filter size question

[noelberg]

Is it better to get the penguin biowheel 125 gph or the 170 gph for a 20 gal tank?
I think I'm underfiltered right now, and the first is for 10-20 g tanks, the other is for 20-40 g's.

There's a sale at Petco.com right now
petco filters

 

[noelberg]

PS the one i have now is 100 gph

 

[Shizat]

I think the rule of thumb for fish tank filters is multiply your tank capacity by 5 and that gives you how many gph you need. So 20x5 = 100gph is at the minimum but bigger is not always better.

 

[Bol]

Most manufacturers do seem to use that 5x total gallons "rule" for sizing their filters.

Many hobbyists recommend something closer to 10x. /shrug

The problem that sometimes arises, though, is that you get too much water disturbance. Unfortunately, the Penguins do not have any direct flow controls (at least my 170 doesn't). I've got a 170 on a 46 gallon tank, and frankly, I think it would be scary to have in a 20 gallon (a 20 "high", especially). On the other hand, while I think the Penguin 125 would certainly be sufficient for your tank, I'm not sure it would be worth the upgrade.

What is your current filter (make, model)?

 

[noelberg]

Thanks for the info. Current filter is a Penguin biowheel mini in a 20g high tank. My friend said it should be sufficient, and I haven't had any problems so far ... I'm playing around with the idea of getting out the 5g tank in my basement for either a betta tank or quarantine.

 

[Adrinal]

Bigger is neerly almost always
1) over time cost effective
2) more surface area for bacteria to grow.

I have never seen the water flow from a HOB filter be too much for the tank it can fit on... any kind of filter for that matter.

Full on planted tanks would be the only acception. Rainbows neons zebras will welcome any more flow.
cats will sit in the extra o2
cichlids will hide in rocks...

bigger is better in this case!

yes over 20x overturn may... may be too much

sometimes dithering the water with a rock or plants is neccesary.

 

[Adrinal]

I just realized I never answered your question...
I would at least get thw 170!

Yep, I just checked, I have a 170 on my 10 gal grow out and IMO I could easly go with larger... infact there is no way I would go as small as this 170 on a 20 gal tank I mean to be used as a FO tank. The water flow does not even cause the baby fry to move if they sit still on the bottom... and there is no plants or gravel.
That rating stuff on tanks is BS. It Can do the job... but I would get larger for sure! Better to get a large one now to find out you need a seccond latter.
A small can would be best. IMO

 

[Bol]

Out of curiosity, noel, why do you feel you're underfiltered right now?

 

[noelberg]

Maybe I'm not underfiltered .... I read somewhere that the mini was only recommended for up to 15g tanks. I think I'm just overly anxious right now with my fish since it's a new aquarium. I don't want to be a deadbeat fish-dad!

I'm thinking about using the biowheel mini for my 5 gal and getting a 125 for the 20 gal. Gotta cycle the 5 gal and get a hood so I can use it for quarantine.