Filter question: Two 20s on a 55g?

We currently have two AquaClear HOBs on the tetra's 55g (filters are a 50 and a 30, I think). We recently bought a Marina Slim HOB 20 for the tequila's 33g tank as the AquaClear we originally got would not fit between the tank and wall (this tank also has two sponge filters running). I have quickly discovered that I love these Marina filters, namely because the motor is in the water and it needs absolutely no priming to start, which is important for us with our frequent power outages.

I would love to switch the tetra tank over to these filters, but the biggest Marina HOB that I can find is a 20. The 55g has only 14 black skirt tetras, and we do not plan to add anyone else - it is their turf! Would two Marina HOBs be enough for a 55g with this stocking level? I checked AqAdvisor and it says we would have plenty of filtration capacity - but I generally only use AqAdvisor as a 'guide,' not as the ultimate answer! I know that, with filtration, more is better, but a part of me thinks that this is not as big of a deal with such a small bioload....?

Any thoughts?

Hmm. For the stock level it's probably reasonable but for the volume of the tank (etc turnover rate) I'm not sure it would be sufficient long term. You might get away with it, but personally I would be hesitant to just go with a 20. I'm sure others will weigh in too.

CAAIndie wrote:Hmm. For the stock level it's probably reasonable but for the volume of the tank (etc turnover rate) I'm not sure it would be sufficient long term.  You might get away with it,  but personally I would be hesitant to just go with a 20. I'm sure others will weigh in too.

Thanks Indie, I appreciate your input. Two 20s seems low in a 55g to me as well, but when I think about the bioload (14 black skirt tetras) I get the vibe it might be okay. My vibes, however, are not always right! So, I am, of course, hesitant...I am now half considering leaving the 50, and replacing the 30 with the 20...at least then in an outage, one filter would come back on if we are not home...?

Shell wrote:

CAAIndie wrote:Hmm. For the stock level it's probably reasonable but for the volume of the tank (etc turnover rate) I'm not sure it would be sufficient long term.  You might get away with it,  but personally I would be hesitant to just go with a 20. I'm sure others will weigh in too.

Thanks Indie, I appreciate your input. Two 20s seems low in a 55g to me as well, but when I think about the bioload (14 black skirt tetras) I get the vibe it might be okay. My vibes, however, are not always right! So, I am, of course, hesitant...I am now half considering leaving the 50, and replacing the 30 with the 20...at least then in an outage, one filter would come back on if we are not home...?

For some reason I missed in in the original message/title, but I thought you were putting just one 20 in too. That sounds like a better solution to me personally (the 20 with the 50 still going).

CAAIndie wrote:

Shell wrote:

CAAIndie wrote:Hmm. For the stock level it's probably reasonable but for the volume of the tank (etc turnover rate) I'm not sure it would be sufficient long term.  You might get away with it,  but personally I would be hesitant to just go with a 20. I'm sure others will weigh in too.

Thanks Indie, I appreciate your input. Two 20s seems low in a 55g to me as well, but when I think about the bioload (14 black skirt tetras) I get the vibe it might be okay. My vibes, however, are not always right! So, I am, of course, hesitant...I am now half considering leaving the 50, and replacing the 30 with the 20...at least then in an outage, one filter would come back on if we are not home...?

For some reason I missed in in the original message/title, but I thought you were putting just one 20 in too. That sounds like a better solution to me personally (the 20 with the 50 still going).

oh, I think you read it right the first time (at least mostly!), I am considering putting in two filters rated for 20g each.

Putting in just one 20, and keeping the old 50 was an after thought...

Someone gave me a tank a while back and it had one of those Marina Slim 20's. I initially loved the idea of the pump being in the tank for the self priming feature. However i quickly found out that they gooped up fairly quick and needed a extensive dismantling in order to clean it all out. After doing it a couple of times I got POed and launched it into the woods.

But that's just me and my super pooper fish

I will say a couple of pot scrubbers fit perfect in it.

Steve

Hmm. Those are small filters. If they are rated for 20 gallons, they are good for 15. So they will provide 30 gallons of filtration, in a 55 gallon tank. You are lightly stocked though.
Let me suggest an alternative. You could buy a maxi-jet type powerhead (a 900) and position it on top of a large hydro-sponge filter. The contraption would be fully submersed, and cost $43.13 at Mops, pre-taxes and shipping. It would provide self-starting filtration that would allow you to throw in another 25 blackskirts if you wanted, at a reasonable cost. As long as the powerhead has a base that can extend into the sponge filter set up, it is easy and efficient. It's quiet as well, and the maxi-jet pumps are extremely durable.
Just an idea...

So, the time has definitely come to move forward with a change in filters in this tank. I have been doing a few more WCs than normal on the black skirt tetra tank as Jack is displaying white on his tail fin and skirt. When I went to pull the AquaClear 50 off tonight to give it a cleaning, I pulled a big chunk of paint off of the wall! It is too darn big!

So, we are looking into your idea Gary, I just want to make sure that we do not add any more of a current as these guys do not do well with a high flow. I am also now half considering replacing the AquaClear 50 with a Marina slim 20 (with only 14 black skirts, I can't imagine there would be too much of an issue with gunk, as you mentioned Steve - but, again, you just never know!). I say the 50 now as this is the filter giving us the most trouble.

The other option is to drain the tank down to about 30% and move it out a bit - but I am not liking that option at the moment! The stand is hollow, so I have visions of the whole tank plopping over if we tried to move it!

I'm a big believer in overfiltering. If a filter is rated for 20g, it is good for 15. My 120 has filtration for a 200, for example, and that is barely enough.
I would move that tank out. I'd drain it to an inch or so, and slide it out 2 inches.

I use live plants as a back up filter. As long as there is some natural light coming into the tank, they will continue to photosynthesize and convert your poop into nutrients. This has proven to be very useful for me when they cut the electricity once in Mexico and I was away for almost a month.... No harm was done; all fish were alive.

I have Two 70s and Two 50s on my 46 Gallon

But the water is really clear

Thanks guys - I too believe in over filtering, and we do so with all of our tanks. There is only one live plant in this tank (and two moss balls - not really plants!), and I am not sure we have the time (or patience!) to turn it into a planted tank at this time - too much going on here! Hmmm...maybe we will have to move the tank out a bit - grrrrrr...I dislike moving tanks with 'fish in'! That will have to wait until after Christmas as we would need at least two good strong bodies to help! That's again for the replies - much appreciated!

I am a believer in quality filtration not over-filtration. Such and such gallons per hour do not replace quality filtration. Are there ways you can add better filter media to the filters you have? Stuff some pot scrubbers in where needed and let your water tests be the judge of your water quality. If you can go a week or more without drastic water quality issues you are good. Circulation can also help weak filters do their job. A cheap powerhead or circulation pump could improve things by moving debris around and getting all the water through the filtering systems.

That being said there is nothing wrong about over-filtering as long as the outcome is water quality.