HOB flow slows down every week?

tiger_cory

i'm the pie
Jul 5, 2013
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Alberta, Canada
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hello
Hey guys, so the flow on my HOB filter (marina s15) slows down every week. I've found that cleaning the impeller every week gets the flow back up to normal for 1-2 days before it slows down again. When I take out the impeller to clean it, it usually isn't very dirty. This has been happening for a few months now. What do you think the problem is? Should I get a replacement impeller, or is this an issue with the motor? Thanks!
 
If its clogging up every week, you may have too much bioload for the filter to handle and either need to look at your stock relative to tank size, how much you feed, or look at the filter rating.


What size tank? What are the fish species and numbers? Feeding plan?

All of these can lead to filter issues.

Ideally we still need to clean the filter at least 1-2 times a month for it to clean well, but every week might mean something is up.
 
tank size - 10 gal
fish - 4 neon tetras and 1 bristlenose pleco
feeding plan - flakes once a day for the tetras, and I drop in a fresh broccoli every day for the pleco so he always has something to munch on.

The tank is pretty heavily planted, I've got a bunch of hygrophila polysperma, riccia, and salvinia in there

Maybe I'll try cleaning out the sponges? I modified the filter so that it's just sponges in there, instead of the media that came with it. It never occurred to me that they could be clogged, since I've been focusing so much on the impeller... but I'll give them a rinse today and see if that fixes anything!
 
The bristlenose pleco is the problem... theyre high bioload--meaning they poop a lot and often. Theyre best suited for tanks 30 gallons and up because of the waste and the size they get (3-6")
A 10g filter cannot handle the waste they give off.

So I would suggest a few things here...

1)get a bigger tank (at least a 30 gallon) and more filtration (make sure to transfer your current filter media over to the new tank and/or to the new filter if you get a much bigger filter)

OR

2) rehome the BN pleco, keep the 10g but make sure you add more neon tetras, they need shoals of 6-10+ to feel more secure. A 10g is a bit small, but if space is an issue, you could do *only* neon tetras in the 10g setup. Regardless if you upgrade tank or keep the 10, you should address the schooling need of the neon tetras.
 
I’m betting it’s clogged sponges. Don’t rinse them in tap water unless you know for sure there is no chlorine. Take out some tank water into a bucket and swish it in there.
 
Sorry if I missed it, but does this HOB also do this when you leave it in factory form?
 
Sounds to me as if part of the problem is clogging intake tubes, then exacerbated with sponge partial clogging. In my experience, the first (intake tubes) occurs relatively fast, and reduces flow most substantially. Whether you use disposable cartridges (nobody should be doing that!), sponges, or your own DIY changes little the history above.
I have solved that issue by adding prefilters to all intakes. After trying various types over the years (i.e, cutout sponges, etc), I settled down on my own standard (a small piece of plastic screen mesh, held by rubber bands) (picture attached, on Aquaclear 110). I use this on all filters, HOB and canisters. The rubber bands last about a month, the screens several months. I once bought a roll (< $8), and will last me forever.
Weekly I clean all prefilters (meshes) and sponges/noodles (HOB) and canisters' interiors monthly. Using this method, I only rarely have a filter that over the week slows flow sufficiently to be a concern. And this is even having floating frog bit and Salvinia.
Also in my experience, using this method I don't actually clean the impellers more than every few months, at which time I also grease them well. Some impellers have been going for quite a few years, but of course replacements are sometimes needed.
My opinion ? Pre-filters forever, and planning of cleaning them weekly.

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