# Exactly how does the flow go thru HOB filter?



## JJ09 (Sep 11, 2014)

I have an old marineland penguin HOB. It came with carbon filter cartridges. I cut them open to remove the carbon, and then later on cut off the sheet of blue filter media, kept the plastic grid to hold things off the wheel, and put in these sponges








in the order you see (blue filter media pieces aren't in there anymore, I kept them for a while to transfer the bacteria). Also put in a stack of ceramic bio cubes under the wheel where there's a little gap but I don't know if they do any good there.








I've had it like this for over a year now. 

I'm going to get poly quilt batting to put after the finer sponge, to try and clear small particles out water column. Now rethinking how I have my filter media. Does the flow go like this, from side with the intake out side with the media in a back-to-front manner (sketch is looking down on the box)? 








Or does it go from bottom to top of the HOB chamber (sketch is looking at side of the box)? Maybe I should cut the sponges different so they stack, and put the biocubes on top of it all- see drawing.









If somebody already answered this elsewhere, can you point me to it. I did a search but didn't find anywhere describing what I'm asking.


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## Leeatl (Aug 8, 2015)

It goes like the first pic .


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## JJ09 (Sep 11, 2014)

Ok so my media arrangement is fine? thanks


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## Leeatl (Aug 8, 2015)

Yes it is fine , but I would consider getting a better filter depending on the size of your tank .


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## JJ09 (Sep 11, 2014)

It's a 38. I always assumed I had decent flow- there's a good amount of ripple across the surface, most of the plants wave gently and the fish have to struggle in one corner against it. It stays fairly clear, only when the light's on and I lok close see particles


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## Bandit1200 (Dec 11, 2010)

I think the flow is going to be a combination of both directions, especially as the sponges become clogged.


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## JJ09 (Sep 11, 2014)

It's a 38 gal. There's a good amount of ripple across the surface, most of the plants wave gently and the fish have to struggle in one corner against the flow. Water stays fairly clear, only when the light's on and I look close do I see particles. It's not good enough?

Of course when it just up and dies, I'll get a new one, but what kind is better.

Bump:


Bandit1200 said:


> I think the flow is going to be a combination of both directions, especially as the sponges become clogged.


Hm- so maybe it doesn't matter which way I arrange the media?
I do rinse them out every other week.


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## Leeatl (Aug 8, 2015)

If you look at your pic here , the water comes out of the right hand section into the left . The way you have it now most of the debris is getting caught in the area circled in red . I would take one of those sponges out or get a thinner one . You need to have an empty cavity behind the sponges so the water will contact the whole sponge as it passes . Hope that makes sense .


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## PlantedRich (Jul 21, 2010)

I also see it as LeeAtl describes. Not all HOB do it the same but for this one. The water comes up the intake and then needs to go behind the first sponge as circled in red. When it is this tight, the water can only go more or less into the side of this sponge and then into the lighter grey and out the front. You may be able to tell where the water is flowing best by looking at the media when it gets dirty. If the red circle has all the dirt and debris, it may be because the rest is just setting off to the side and not getting much flow through it at all. 
Where to place the bio-media is more a matter of how you think about cleaning. If you place bio media at the start, it can let the tiny little holes and crevices where bacteria grow get gunked up and full sooner than if the bio media is only dealing with water than has the major debris screened out first. But given time, there is good bacteria all over everything in the tank and bio media set specifically for that becomes less important unless we are really pressing hard on being overstocked so that we need total high performance from the bio media. 
For HOB design, I like the Aquaclear models. They move the water into the bottom and then is spreads out under the first media and then moves upward through each layer. They tend to be easier for me to adapt and change media to suit each tank better.


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## Leeatl (Aug 8, 2015)

I have used the Penguins of all sizes from the 100 to the Emperor for years . They are decent enough but lack in media choices . The 3 largest ones come with refillable racks now and I got them years years ago . They help cause you can use Matrix or crushed coral or whatever you want in them . All of them work the same way as Planted rich and I have said....flow from right to left and back to front . I have read "tests" that say the bio wheels don't do anything....I do not know but I use them and they get really gunky so something is growing on them...lol
I now prefer Fluval C series and a lot of folks use the AC's , but I still hang on to my Marinelands and have a couple in use .


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## thedood (May 30, 2015)

I agree with @Leeatl as well and have the same experiences. If the op wants to continue using the current hob then I think they have been given good advice. The way I set mine up was remove the blue pad, zip tie floss to the plastic insert, fill the remaining with biomedia, as they have done, all the way to the top. I also run a prefilter on mine.


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## thedood (May 30, 2015)

In case your wondering why I remove the blue pad it is so I can dump the carbon out. I get course mech filtration from the sponge prefilter and get finer filtration from the floss. Leave the top open and you can stuff a purigen pack down in there as well.


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## JJ09 (Sep 11, 2014)

Thank you everyone yes, that is clear to me. I thought stuffing it w/more media was usually better, but it makes sense that the water has to go behind it. I will pull one of those sponges (squeezing it out all over the remaining one) and only add the poly batting if its thinner than the removed sponge and can leave a gap in the back.

I do have a prefilter sponge on my intake. That is usually the dirtiest thing when I rinse. I can't skip rinsing it every other week, whereas sometimes I go three or four weeks between rinsing the stuff inside the HOB box.

Yeah I've also read reports that someone did a detailed test to see if the biowheel actually does anything. And supposedly it does _except_ if you have hard water- which I do- because then the deposits clog the media and make it inhospitable for the bacteria? But I've noticed that a few times when my wheel quit turning and flow was still going thru the filter, water quality quickly went downhill. So I think it must have an important function. 

It's the filter that came along when I got my tank and after I got it all running I just didn't feel like changing it. I've been satisfied w/its performance but sure glad I asked about now. 

So- the ceramic bio cubes are good where they're at? I only have them stacked two or three deep in that gap right where the water exits, but have more and can fill to the top if it is beneficial.

Bump: I have noticed that the coarse sponge rarely has gunk in it- usually the finer one (pale gray) is the one needs rinsing. Probably because the prefilter on intake gets most of the bigger debris out. So I'll pull the coarse sponge.


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## PlantedRich (Jul 21, 2010)

I think we are all talking pretty much the same idea now. something that we want on almost all filters is the way the water moves through. We want it to use all the media so first it needs to spread out from where it enters. On the Ehiem Classic line, they have a grid that stands up on legs about an inch off the bottom. On top of that grid is are barrels. They have holes at least an 1/8 wide so they only catch really big stuff like leaves but they do act as a "maze" which makes the water spread out over the full width of the bottom before heading up. Then the next layer is often course sponge to strain out the heavier stuff before passing it through to the bio-media. Some put a finer sponge, either before or after the bio. But many do use a finer floss or sponge to "polish" the water going back to the tank. HOB are dealing with less room but do pretty much the same. A couple items to strain things before passing through to bio and then maybe fine filtering to improve the "look" of the water. Where and how each layer is set depends on what that tank and user finds. 
My tank has lots of bio to take care of my larger fish while my daughter needs more mechanical to clear the water as she has catfish that stir the bottom a lot. 
I like bio wheel ideas but they tend to be funky to keep moving. 
Filters are never exactly right but then most can work real well if we give it a little tweaking to fit best.


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## JJ09 (Sep 11, 2014)

Changes to my filter yesterday. Image only shows left side of the HOB. I took out one sponge and cut a piece of poly batting to fit between it and the plastic grid panel, and have bio cubes between that and the outflow- they're really filled almost to the top I added more after I took this picture.








Tried to hold them in the spot in a mesh bag at first. Later in the day noticed some overflow through the spillway. Took it all apart again several times- it turns out the flow was blocked because the poly was doing its job! In just a few hours it had turned from white to dark gray/brown, and was clogged with gunk. I rinsed it out in tank water in the bucket, but still had a little overflow until I took the cubes out of the bag and just dropped them in the spot. Not sure why that was slowing it down.








Tank water already looks cleaner- visually there are far less particles- but when I tested it surprised at the result. I expected an ammonia or nitrite spike from removing part of the sponge, but instead found high nitrates 80+. Maybe there was an ammonia spike and it resolved quickly into nitrates? or I inadvertently fouled the water when messing with the filter on/off. Regardless, I did a partial wc and got nitrates down to around 40. Tomorrow will do another one.








The flow is a lot stronger now. As soon as I had it going properly again, the cherry barbs were very active in the plants just below the outflow. I wasn't watching them closely but I am pretty sure they were flirting, sparring and spawning again. This morning dismayed to find one of the females is missing half her tail! I can only think one of the other fish bit it in a fight. Hope having the water cleaner will help her heal.


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## PlantedRich (Jul 21, 2010)

Missing part of a fin is kind of routine in my tank of cichlids and they do grow back. I am very slow to go to medicines as so many of them also wipe out the good bacteria. That can put your tank into what I call the "death spiral" of using meds to clear a disease and finding the whole thing is in turmoil due to losing the cycle. 
But there are two meds which I keep on the shelf for low level things that I want to clear before they get worse. I find Pimafix and Melafix are both safe to use as well as cheap enough to make it practical. I will not spend more on meds than the fish is worth unless it is a very nice fish. I find a shot of Meal and Pima can give me some pretty cheap insurance even when I am not good enough to say exactly what disease may move into the injury. 
Kind of like aspirin for the tank? Not sure of the problem but I feel better when I use it!


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## JJ09 (Sep 11, 2014)

Ok but how are those meds with scaleless fish? I have otos and kuhli loaches in there... I do have both melafix and primafix on hand, but haven't used them in a long time because up until recently I had a betta in each tank. 

I've seen fins grow back too- one of my smaller males had a piece missing of his tail a month or so ago- it grew back clear at first and now has full color. And over a year ago I had a cherry barb with tail rot- for her I put into QT and did water changes twice a day to keep it really clean, it grew back completely. This was just a shock, to see an entire half the tail missing. I didn't know my barbs would be so mean to each other.


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## JJ09 (Sep 11, 2014)

Filter was still not quite right- yesterday I noticed a trickle coming down the spillway, and this morning it was a steady little stream. So during maintenance I turned it off and pulled the media out again- no clogs. Lifted out all the bio-cubes and thought about this: 



PlantedRich said:


> ... something that we want on almost all filters is the way the water moves through. We want it to use all the media so first it needs to spread out from where it enters. On the Ehiem Classic line, they have a grid that stands up on legs about an inch off the bottom. On top of that grid is are barrels. They have holes at least an 1/8 wide so they only catch really big stuff like leaves but they do act as a "maze" which makes the water spread out over the full width of the bottom before heading up.


There's ridges in the bottom of the HOB box, both sides of the panel, maybe they have a purpose. Smaller bio-cubes settle down between them. I took them all out and replaced with larger, ring-shaped ceramics. (Half were already those type anyway). Put it all back together and voilá! No more overspill. Not even the smallest amount. I forgot to replace the loop of fishing line that held the sponge and poly batting onto the panel, but it doesn't seem to matter- the flow holds them in place. Very pleased. Fishes are playing again.

This was in the morning. I've looked at the filter every time I walk by the tank, and still the overspill remains clear. How quickly do bacteria colonize the media? Three days ago I took out part of that sponge, and added more small bio cubes and some ceramic rings on top of that. There weren't very many of the bio cubes in there to begin with, maybe a dozen or so. Today I took out all the small bio cubes and replaced with ceramic rings. Hope I didn't disrupt too much at once.


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## JJ09 (Sep 11, 2014)

Now I'm not sure what to do with all the little bio-cubes I took out. I hate to throw them away. I suppose if I dry them out, I can save them for future use when I might have a different filter? They've been rinsed.


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## Leeatl (Aug 8, 2015)

JJ09 said:


> Now I'm not sure what to do with all the little bio-cubes I took out. I hate to throw them away. I suppose if I dry them out, I can save them for future use when I might have a different filter? They've been rinsed.


Keep them they don't "go bad" . I have a bunch of different such media in storage . If I need to start a new filter I just take some out of an established filter and replace with new...almost instant cycle . I do run at least 2 HOB's on each tank so I don't mess up the established tanks cycle by doing this . 
I still say I think you would be happier with a different HOB for that tank . That one is so small that finer debris will clog it faster . I bet you will have to redo it again Sat or Sun because of this .


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## JJ09 (Sep 11, 2014)

Is it really... ? The width of the filter box is a fourth the length of the tank. My model is discontinued, but I figured that if the 150 model is rated for a 30gal tank, the 170 (mine) would be fine for a 38gal. How do you judge. I know now that it's not really designed to put different kinds of media in it, so for that alone I will probably go with a different kind when this one is kaput- but otherwise... ? help me understand.


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## Leeatl (Aug 8, 2015)

On these filters the width is not as important as the thickness , IMHO . If you are using a prefilter sponge , I would just take out all the ceramic..etc and use a sponge/quilt batting inside and the bio-wheel . That will be plenty of surfaces for bio to grow . Just rinse the sponges in tank water when dirty . You can have a thin piece of fine filter material , but only to polish the water . Point is you want as much flow behind the filter material as possible for max effect .


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## JJ09 (Sep 11, 2014)

Ok, yes that's what I've got now. Prefilter sponge, sponge in the HOB with one piece of poly after it for fine particles, and then some of the larger ceramic rings. I guess I just thought it was big enough because when I eyeball the filter, it looks large on the back of the tank.


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## PlantedRich (Jul 21, 2010)

I think you may be okay but then it does change with each tank and how we each mange the tank. How to tell what works is a matter of how you feel at times. I suggest not rocking the boat very much at all when a tank is newish. After a tank has been up and running for months, there will be a coating of good bacteria just about everywhere that you've not been wiping down. Things like the bottom, plants and the tank walls get bacteria after a while. The filter is designed for this with the bio-media having all kinds of little, tiny nooks and cracks for bacteria to hang out. Kind of like an apartment building but they can also be lots living outside on the street? 
So after some time, moving and changing things like media is less prone to killing off too large a percentage of these good guys and you can do more at one time without seeing any spike. You may have seen/heard of people doing their cleaning and using tap water with chlorine? Yes, it can be done but it is far less dangerous if the tank has a good coat of bacteria all around. Not something I recommend but I wish folks would explain why they can do bold things like that. 

How well the current filter works may be as simple as asking how often you need to clean the sponge. Too often and it's a pain may require changing the filter or some other move. But if it works and fits your schedule in life, no reason not to go with it. In theory, we could all go without a filter--if we changed enough water! But for most of us, we change water when we need to but like the filter to keep us out of trouble in the meantime.


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## Leeatl (Aug 8, 2015)

My bad , it looked like a 100 or so when I looked at the pic you posted . It should be fine . I use a 200 on a 25 gal and it works fine . Just keep watching and tinkering if need be till it works for you .


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## JJ09 (Sep 11, 2014)

Thanks, guys. Yeah- right now I rinse out the prefilter sponge every other week. The sponge inside the HOB once a month (I usually forget about it until flow reallly slows down). The filter on a little airpowered sponge I have in opposite corner (just to prevent a dead area) gets rinsed even less frequently- maybe once every other month- it just never seems to collect much mulm. Now that I've got the flow different I'll have to keep an eye on it and see when things need it I guess. 

It's been established just over a year now, so I don't feel quite as nervous messing with things... like moving plants around but filter stuff always seemed like a bigger deal.

No way would I ever think putting straight tapwater in the tank! I've never heard of anyone doing that- didn't know it was possible to be safe w/that... but it makes sense when you explain it.


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## JJ09 (Sep 11, 2014)

Leeatl said:


> I still say I think you would be happier with a different HOB for that tank . That one is so small that finer debris will clog it faster . I bet you will have to redo it again Sat or Sun because of this .


You were right. Here it is just the next morning, and there's water over the spillway again. 



Leeatl said:


> If you are using a prefilter sponge , I would just take out all the ceramic..etc and use a sponge/quilt batting inside and the bio-wheel . That will be plenty of surfaces for bio to grow . Just rinse the sponges in tank water when dirty . You can have a thin piece of fine filter material , but only to polish the water . Point is you want as much flow behind the filter material as possible for max effect .


Ok, that's where I'm going now. I removed all the ceramics and looped the sponge and batting onto the panel inside the box with fishing line again- hold it more snug. If it keeps overflowing, I guess I should either take out the sponge or the batting, and just have _one_ thing inside the HOB? Maybe there's something else I can use to polish the water- finer poly fiber? I thought this quilting batting was plenty thing- it's made for baby blankets- but guess not. It does have some fluff on one side, which I didn't realize until I opened the package.

I really do like the look of the tank with clearer water. I don't want to have to take out the poly, now that I've seen what it can do... (My husb says why are you so stubborn? Just go buy a new filter already. Ha.)

Bump:


thedood said:


> I agree with @Leeatl as well and have the same experiences. If the op wants to continue using the current hob then I think they have been given good advice. The way I set mine up was remove the blue pad, zip tie floss to the plastic insert, fill the remaining with biomedia, as they have done, all the way to the top. I also run a prefilter on mine.


What do you use for floss, exactly? I put polyester quilt batting in, but it is clogging so maybe something diff would work better.


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## Leeatl (Aug 8, 2015)

Take the finer stuff out and wait a few days . As the coarser pad clogs it will catch smaller particles until it is polishing . You may have to live with a little overflow to maintain the clarity you want . I use quilt batting and sponges mostly .


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## JJ09 (Sep 11, 2014)

Ok. I tried it again two different ways today. Now have it: prefilter sponge, in the HOB two layers poly batting against the plastic panel, ceramic rings after. No overspill and it's been four or five hours. But I'll have to wait a day or two and see if its ok like this... I don't mind if I have to rinse/change the poly once a week. But maybe having two sponges is redundant? especially if the prefilter one is already getting all the big particles out.


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## JJ09 (Sep 11, 2014)

Thought: will using the poly batting to polish the water help reduce algae? I have some that's just noticeable if you look closely. I just wanted the clear water look, but if cleaning fine particles out gets rid of some algae, it would be a big plus. Easier for me than fiddling with the light intensity or ferts dose (or even how much I feed the fishes) again...


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## Leeatl (Aug 8, 2015)

The short answer is no . Just have to balance the tank .


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