Canister filter Flow rate, GPH, etc

Hi there!

I'm presently shopping for a canister filter and am wondering if the flow rate can be reduced to accomodate my fish (they all prefer low flow)..
I'm also wondering how silent they are and how efficient they are compared to HOB filters.

Currently my HOB filter blows all the fish out of one side of the tank so the fish are all on one side of it..

I'm also wondering how much GPH I should be looking at for a 46gallon tank?
My tank is planted as well, not sure if this makes a difference?

Keep in mind, my fish don't really like current, I have Rummynose Tetras, CPD and Endlers in there.
I've seen them struggle a bit in the strong current that my AC 70 creates (It's modified with an AC50 impeller so less flow rate already!)

All input is welcomed!

I would certainly suggest a good canister filter here.  Many use HOB but you have mentioned one real issue with these; I gave up on HOB years ago.  I have had canisters on my larger tanks, 70g, 90g, 115g, since 1996, and sponge filters for smaller tanks.

Select a canister rated for a 46g tank.  They all have a rating "up to xx gallons."  Some have flow control, but even if not, there are ways to deal with this.  Most will have a spray bar that can be removed which is useful when you do want more flow, but with the spray bar you can position it along the end wall with the holes directed into the wall at an angle.  This way you can adjust the surface water movement.

Some will say flow doesn't impact fish, but this is not true.  If fish have to work against a current--and remember that the filter is on 24/7--this takes more energy that is better used for other purposes, and it does wear down the fish.  Over the years I have experimented with this and found that many species of forest fish will seek out the areas of the tank that have less water movement when they have the option.  Some fish need current, some do not.  A canister is an excellent filter to provide either, or a happy medium.

Canisters run absolutely silently, at least the good ones.  I have experience with Eheim, Marineland and Rena.  In the view of most, Eheim are the best.  They are more expensive, but they have the track record of reliability.  My two Eheims have been running continually since 1996 and 1998 with never an issue.  You can use non-Eheim media to save money; I use Fluval ceramic disks and biomax media.

Byron.

I am a canister filter fan and have experience such like Byron with Eheim, Marineland and Rena.

Normally people always recommend a 10x turnover rate. In other words, you should be looking for a filter that states they do in your case around 500 gallons/hour. However, with a planted tank you can get away with less.

Normally the recommendations from the manufacturer come down to a 5x turnover and I have good experiences with that in a planted tank.

I prefer spray bars as they provide you with a nice equal flow throughout the tank opposed to jet nozzle type outlets. The power type outlets concentrate the flow and create a stronger current in your tank. So in your case I would definitively go with a canister that has a spray bar. The other advantage of a spray bar is that you have less 'dead points' in your tank and this also helps with avoiding algae.

I personally think that Rena provides the best value for money. Unfortunately though, they are no longer being sold with a spray bar. You might be able to buy it separately from Ebay or another place, but I am not sure about that.

Thank you for the valuable information!

I am leaning towards the 264GPH models as I do have a LOT of plants.

I have another question now, what are the advantages of having 4 compartments instead of 3?
Are UV sterilizers any good? (I have seen a few models with it included..)

I highly recommend the API Filstar canister line(formerly Rena) I have 7, some the 4 tray, some the 3 tray. I have some older Renas, with spraybar. You can easily make your own for the new Filstars. These filters are very quiet, efficient and reliable. My oldest is about 8yrs, runs as well as it did on day1.Another thing I like is they have individual baskets for media, you can customize set up for your tank needs. I have big tanks and big fish, so I use them primarily for bio, with an accompanying AC110 hob or 2 for mechanical. For your 46, a Filstar xpl 3 tray will handle that on its own with ease. While older Eheims made in Germany were top shelf, I believe they are now made in China.. thats a big red flag to me.

I would say it doesn't matter whether you have a 3 or 4 compartments. Internal volume is more important. You want mechanical and biological filtration.

Start off with course filters at the bottom (1 tray), then bio media (1 tray) and a top tray with more biological media and fine sponge for polishing the water as they call it.

Edit: I wouldn't take a filter with an internal UV. If the UV is integrated it is running 24/7 and you will have to change the lamps frequently which is costly. Some people do it to keep their tanks algae free but otherwise you only need an UV to get rid of certain pathogens.

My tanks are all planted, and fish are all small, so as someone mentioned this makes a difference.  The canister rated for the tank size will work fine here.  I never fuss over gph.

On the UV, you do not want to waste your money on this in a planted freshwater tank.  UV will not prevent algae; it can prevent green water which is due to unicellular algae, but it cannot do anything to prevent any other form of algae from appearing and increasing.  It could help with parasites, but only if all the water could be removed from the tank and run through the UV and only then all the water returned; a system of flow-through which none of us has in our home aquaria.  And one detriment to UV, it will remove some plant nutrients that pass through it.

On the compartments...the larger the filter the more compartments.  My two Eheim Pro 2's have two baskets, my Rena XP3 has three; one of these contains four pads (which certainly collect sludge and must be rinsed more often than my Eheims or the flow will all but cease).  Some planted tank aquarists leave the compartments empty, except for one or more pads to do the fine filtering.  With plants you do not want to "encourage" biological filtration as this is competing for valuable nutrients.  I have the ceramic disks in my first basket, then the "bio" stuff but only half full.  I use the filter solely for water circulation, and mechanical filtration.  I realize it is obviously performing biological filtration, that can't be prevented, but it is not being "encouraged" much.

Byron.

Byron Amazonas wrote:On the compartments...the larger the filter the more compartments.  My two Eheim Pro 2's have two baskets, my Rena XP3 has three; one of these contains four pads (which certainly collect sludge and must be rinsed more often than my Eheims or the flow will all but cease).  Some planted tank aquarists leave the compartments empty, except for one or more pads to do the fine filtering.  With plants you do not want to "encourage" biological filtration as this is competing for valuable nutrients.  I have the ceramic disks in my first basket, then the "bio" stuff but only half full.  I use the filter solely for water circulation, and mechanical filtration.  I realize it is obviously performing biological filtration, that can't be prevented, but it is not being "encouraged" much.

Byron.

I don't know much about planted tanks but I would think you would want to encourage biological filtration so the plants could use the Nitrates created?

Steve

Plants most readily use ammonia. They need to reduce nitrates to ause them.

Darn, lost my post!

I encourage biological filtration to get the fish poop and decaying plants available as nutrients for my plants.

The bacteria in my filter help to convert the ammonia via nitrites into nitrates.

Nitrates is one of the big 3 for plants together with potassium and phosphate.

So yes, Steve you are right.

See that horticulture degree wasn't a total waste of my parents money.

Steve

Aggies. Get a life

alexmtl wrote:Aggies. Get a life

Insert image of my tongue sticking out.

Steve

Well l_l_l

You deserve an honest answer. If your HOB is creating too much flow, try a deflector. The dollar store has a suction cup basket that can catch the outflow from the HOB and thus block much of the turbulence. I have used these in my small tanks, all with HOB.

Canister filters are great but the expense is at least twice the price and higher potential for leakage, on the downside. On the aesthetics they are probably the best you can get. As for filtering equivalence you are looking at about the same efficacy. Different ways to access for cleaning the media but that is preference.

For me, I prefer simplicity. High flow, yes. If too much turbulence, look for a deflector. HOB are cheap. Comes down to personal preference.

As to nitrates, I prefer to maximize surface area and I am a believer in undergravel filters. I'll stop there to avoid a war of words and still keep my personal honour intact.

Thank you for your replies and for the hearty debate.
From what I have read on a few other places, plants will be faster at transforming Ammonia than the bacteria. The bacteria will only serve as a "backup" crew, in case plants are not fast enough.

I'm still thinking I'll look for a canister filter but am not ready to buy it for the full price.
I will be patient and look on the local ads and if nothing pops up, I'll probably buy one at boxing day as a christmas present
For now, I'm going to try diverting the filter outflow.

Keep going to garage sales! I got my Eheim at the curb last year and the only thing I needed were new hoses...

l_l_l wrote:From what I have read on a few other places, plants will be faster at transforming Ammonia than the bacteria. The bacteria will only serve as a "backup" crew, in case plants are not fast enough.

Hmm. Got to be careful on what you read on internet forums as posters often repeat misinformation  . I believe that bacteria (and other archaea) are the primary nitrogen fixers in the water system and do most of the transformation. When I get a chance I will post some references on this.

alexmtl wrote:

l_l_l wrote:From what I have read on a few other places, plants will be faster at transforming Ammonia than the bacteria. The bacteria will only serve as a "backup" crew, in case plants are not fast enough.

Hmm. Got to be careful on what you read on internet forums as posters often repeat misinformation  . I believe that bacteria (and other archaea) are the primary nitrogen fixers in the water system and do most of the transformation. When I get a chance I will post some references on this.

Thank you,
I don't like being that poster who repeats the wrong information.

Seconding or thirding the bacteria being the major factor in nitrogen fixation. I can't count tonight.

Biulu wrote:Darn, lost my post!

I encourage biological filtration to get the fish poop and decaying plants available as nutrients for my plants.

The bacteria in my filter help to convert the ammonia via nitrites into nitrates.

Nitrates is one of the big 3 for plants together with potassium and phosphate.

So yes, Steve you are right.

Sorry to disagree, but this is not entirely correct.

Aquatic plants in the aquarium mainly take up ammonia/ammonium as their preferred source of nitrogen.  There are a very few species that prefer nitrate, but the majority prefer ammonium.  In acidic water, ammonia produced by the fish is changed into ammonium and the plants take this up.  In basic water, the ammonia is taken up and converted by the plants into ammonium (some may not get changed, that is another story).  Only when ammonia is no longer sufficient in balance with light and the other 16 nutrients, will plants turn to nitrates.  This is because the plants have to spend considerable energy changing the nitrate back into ammonium, as someone else mentioned, and plants are clever enough not to waste energy if it is not essential.  BTW, there is some thinking that some plants might actually take up nitrite after ammonia and before nitrate, but there is no conclusive evidence.

So the plants take up ammonia/ammonium.  They do this faster than bacteria, according to scientific tests.  However, encouraging nitrification does compete with the plants for the ammonia, depending upon the level present.  Plants can take up a fair amount of ammonia/ammonium, more than would (or should) normally be present in a healthy balanced aquarium.

Turning to the issue of fish poop and nutrients, it is not the nitrifying bacteria that do this, but a very different set of bacteria that live primarily in the substrate where naturally most of the organics accumulate.  There is a host of bacteria, both aerobic and anaerobic, that perform this task.  Snails assist them significantly because snails readily eat all fish waste which breaks it down faster for the various bacteria.  But your nitrifying bacteria are not part of this, at least not principally.  The ammonia produced by the breakdown of organics would be taken up by Nitrosomonas bacteria but again most live plants will take this up first.  There are also denitrifying bacteria that reverse the process, and these too are an essential part of a healthy aquarium.

Nitrifying bacteria are autotrophs, meaning they synthesize their own food, and as they need oxygen to do this, they are aerobic.  The waste control bacteria are heterotrophic, meaning they cannot synthesize their own food so they need organic matter; some are aerobic, but many are faculative anaerobes which means they can survive either in the presence or absence of free oxygen.  Someone mentioned archaea, and there is evidence that these may take over the nitrification in an established aquarium.  But this is a whole new subject.

Nitrogen fixers was mentioned.  It is important to keep these two things separate, i.e., plants taking up most of the ammonia and then the nitrogen fixers.  Plants do not perform this function of fixing nitrogen, they simply take up ammonia/ammonium as their preferred form of essential nitrogen for life.  The fixing of nitrogen occurs through the nitrifying agents, bacteria and/or archaea, and that occurs in any aquatic system.  The end result is free nitrogen, released back into the atmosphere.  However, nitrates will (should) be very low or non-existent using our test kits in a heavily planted aquarium.  This is not due to the use of nitrate by plants, but to the high take up of ammonia, meaning that little (or at any rate less) gets oxidized into nitrite to be oxidized into nitrate.

Hope this has helped, but feel free to question.

Byron.

Byron Amazonas wrote:
Turning to the issue of fish poop and nutrients, it is not the nitrifying bacteria that do this, but a very different set of bacteria that live primarily in the substrate where naturally most of the organics accumulate.  There is a host of bacteria, both aerobic and anaerobic, that perform this task.  

Carbon cycle, phosphate cycle etc. I don't think this is counter to what Builu was stating.

Byron Amazonas wrote:Someone mentioned archaea, and there is evidence that these may take over the nitrification in an established aquarium.  But this is a whole new subject. 

Probably more evidence recently. This should be discussed as it started in Canada.

Byron Amazonas wrote:Nitrogen fixers was mentioned.  It is important to keep these two things separate, i.e., plants taking up most of the ammonia and then the nitrogen fixers.  Plants do not perform this function of fixing nitrogen, they simply take up ammonia/ammonium as their preferred form of essential nitrogen for life.  The fixing of nitrogen occurs through the nitrifying agents, bacteria and/or archaea, and that occurs in any aquatic system.  The end result is free nitrogen, released back into the atmosphere.  

Agreed these are separate. However plants do perform this function of fixing nitrogen, such as floating azolla. Others with symbionts. Blue green algae are also excellent examples. Definition of fixing nitrogen is actually reverse of what you state. Fixing = taking atmospheric nitrogen and converting into plant consumable form.

Interesting discussion. Learning alot and great topics building up !

Very good discussion here.

Now.
I got a hold of a nice filter for a very cheap price this weekend and installed it to my tank.

I'm trying to figure out a way to install the spray bars/filter output to have some good flow, without having too much of it.
I'm very impressed by how silent it is, and very happy about my purchase.
I bought a Via Aqua filter, and set it with a spray bar, running verticaly. I'm going to see if I can make it run horizontaly but at the first try, my Endlers seemed to struggle/fight the current.

l_l_l wrote:Very good discussion here.

Now.
I got a hold of a nice filter for a very cheap price this weekend and installed it to my tank.

I'm trying to figure out a way to install the spray bars/filter output to have some good flow, without having too much of it.
I'm very impressed by how silent it is, and very happy about my purchase.
I bought a Via Aqua filter, and set it with a spray bar, running verticaly. I'm going to see if I can make it run horizontaly but at the first try, my Endlers seemed to struggle/fight the current.

I will assume the spray bar is perforated with a series of holes.  The spray bar should be attached horizontally along one end wall (opposite to the end where the filter intake is positioned, to create a flow down the length of the tank).  You can adjust water movement by positioning the bar so the holes are aimed into the end wall.  You can create some surface movement doing this, as this surface disturbance will vary depending upon the angle of the holes to the wall. Aiming the holes directly downward will produce no surface movement whereas aiming them into the wall will.

Doesn't matter which end you use for the intake and outflow bar; you will probably find that the fish generally remain headed into the flow, even if very slight, so you can have the fish facing left or right in a sense.

Byron.

Thank you Byron for this.

Do you know if the fish do that because they enjoy it, or just because they just "have to".?

l_l_l wrote:Thank you Byron for this.

Do you know if the fish do that because they enjoy it, or just because they just "have to".?

It is a physiological necessity for resting fish because they cannot swim backwards, so they face upstream or into the current in order to respirate naturally with the least amount of effort and in order to remain in relatively the same place.

There is another aspect, namely that fish naturally expect food to be in the current so this is the easiest way to feed.  They also have a fairly high sense of smell and can smell upstream food before they see it.  Characins are particularly adept at this.  Someone, can't remember who, once wrote that if you scatter food on the surface of a South American stream, the characins are inevitably the first to find it.

We are considering fish "at rest" here.  Obviously they can swim in any direction when they want to.  But when resting they will face into the current if there is one.  You do not see this in tanks with no water flow.  I have a 3-foot 33g with a small Eheim inside sponge filter in the right rear corner; the flow is very low.  The group of sparkling gourami prefer still water, so this suits them.  I also have groups of some small rasbora in this tank, Trigonostigma hengeli, Brevibora dorsiocellata, and Boraras maculatus, and these face in any direction as the mood strikes them.  The last species tends to not shoal tighltly, so they can be scattered here and there, facing different directions, but the first two are fairly tighly shoaling fish and remain in a group (both of these species always mixed together, interestingly) facing various ways but all together.

This is just one of the reasons I always advocate providing the most natural environment as one can; the natural behaviours of the fish will be more evident.

Byron.