FishProfiles.com Message Forums

I have an 18 gallon tall fresh water with a Penguin 200. This HOB filter is good up to 50 gallons. Is it correct for me to assume that this quite oversized filter would further accommodate the use of NO pump? I assume that there will be considerably higher agitation and current flow than the smaller but adequate Penguin 100 (Up to 20 gallons) which is 2 models down and signifigantly smaller. As soon as I turn off my pump, my tank instantly seems so much more peaceful. I am like many that just feel uncomfortable after a while and turn it back on, but I have to think that this over-sized filter has got to be more than enough to oxygenate the water adequately. But, I am no expert, hence the question. And I do have some live plants and do not use CO2. Thanks in advance.

Hi,
Welcome to FP!
There are some intangibles that go with answering your
question. Many filters are packaged with the "For tanks
up to xx and even xxx gallons." It would probably be
better if they said "for tanks between 30 and 55."

Personally, I would use the smaller filter on your specific
tank.

Filters with too high an output, confined in a
small tank, give currents that can stress the fish, and
even prevent plants from properly anchoring themselves in
the substrate because the plants are worried loose before
the roots can take hold, High currents can stress fish.
While many enjoy frolicking in the currents, all of them
have to have something they can rest behind out of the
high currents.

Conversely, tanks with too little current, can become
stagnant and the water "layer" into areas of poor
oxygenation. Little or no currents prevent the distribution
of nutrients for the plants to feed on. Little or no
current can also help promote the growth of algae such
as the dreaded blue green algae.

If you keep your bio-load (number and size of the fish in
the tank) between "normal" and "light" the smaller filter
would be ideal for your situation. Turning a filter on
and off is generally not a good idea. The bacteria that
live in the filter depend upon a constant flow of water
to provide nutrients and oxygen for them to live on.
Turning it off can starve them of oxygen and that can
promote the growth of anaerobic bacteria (not good) that
can cause problems. The lower current will also allow
the plants to grow and better anchor themselves into the
gravel, which in turn will promote better growth.

In short, I would go with your "gut" feeling and use the
smaller filter.

Frank


-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--

Ah!

Take a look at this thread that I posted last night!

Some fish species require modest but not overpowering currents. So if you have Cardinals or similar fishes in there, go with the more modest filtration setup.

Other fish species, however, will welcome strong currents. My Panda Corys fall into this category (they surf the powerhead bubbles because this current resmebles that found in their native waters) and some Loricariids will welcome even stronger currents. Basically, if your fish species is native to a fast flowing, well oxygenated river system (Hillstream Loaches are classic examples of these) then you put them in an aquarium with an 'over-powerful' filter.

At the opposite end of the spectrum, numerous Labyrinth Fishes are natives of still waters in the wild, and will NOT appreciate a strong current. Bettas, Dwarf and Honey Gouramis etc., will need only a modest turnover, and will make up any oxygen shortfall by breathing atmospheric air.


Panda Catfish fan and keeper/breeder since Christmas 2002

Thanks for the replies. I think you misread my post Frank. Anyway, It is not the filter that I want to turn off, it is the noisy pump. I get more current and noise from that than my filter by far. My filter is oversized for this tank, but the current generated is not bad at all and I am very happy with it. Remember, this is an 18 tall tank. From mid-way down the current is almost non-existent and my plants hardly move at all below mid point. With the pump off, there are still a good amount of small oxygen bubbles populating the tank from the filter which leads me to think that there is plenty of gas exchange going on without the bubbler. From what I understand, the oxygenation process happens at the surface anyway and the bubbler really isn't doing anything different that my filter in terms of oxygenation. I have a couple platys an angel, a bottom feeder and some tetras that are not having fun durring the cycle of the tank. Lost a few already. I am showing nitrites now. so almost there. Anyway, like I said, when I turn the bubbler off, the tank goes to instant relaxation mode. So much calmer. Anyway. Just curious to what you guys think.

Hi Top, and welcome. What pump are you talking about? It sounds like maybe your air pump? You may be correct in your assumption that your air pump is not needed. Yes, the oxygenation does happen at the top by means of an air exchange with the water, as the bubbles burst the outer shell of the bubble is very thin and the oxygen enters the water there and then the oxygenated water(from the burst bubbles)falls back into the water. Anything that creates turbulence will do it. The way to tell would be to shut off the air pump and observe closely. If the fish seem to move close to the top of the water and appear to be gasping for air, especially in the early morning then they are not getting enough oxygen and you do need your pump.
That being said, I have two tanks, one takes air(my 29) and the ten does not. All the fish are healthy and happy. I could turn the air on in the 10 but I don't like it and the fish don't seem as happy with it on either.
If I do turn it off on the bigger tank then in the morning (when there is less oxygen in the tank from your plants using it during the night) the fish do hover close the the surface wanting air.
If pump noise is your problem there are several things you can do. First thing would be Buy a Rena air pump (I believe they are some of the quietest pumps out there), and don't listen to the rating on the box, get the smallest one they make. You'll be valving it down anyways. look at your hoses, are they vibrating against something? that makes a lot of noise. Try hanging the pump in a sock behind the tank, or setting it on a soft surface. I had one that vibrated like crazy, I set it on a mouse pad and I almost could't hear it.
Hope this helped

Allow me to issue a correction here.

Gas exchange takes place throughout the entire surface area of a body of water. This is why, for example, a 20 gallon tall aquarium with modest surface area has a lower holding capacity for fishes than a 20 gallon long, shallow aquarium with a much greater surface area.

If the body of water is stagnant, then exchange of oxygen for carbon dioxide is relatively slow, because the only carbon dioxide that can escape readily and be replaced by oxygen lies within a narrow thickness of water close to the surface - the rest has to diffuse upwards to be exchanged, a long and slow process. Once the water is agitated, however, and a constant current is set up, deoxygenated water is brought to the surface for gas exchange, and the rate of exchange is vastly improved - in effect, you permit gas exchange to take place throughout the body of water in the aquarium by the simple expedient of bringing water from the depths up to the surface in a continuous cycle.

The only purpose that bubbles from an airstone serve in this regard is to create the current - the bubbles themselves are in contact with the water for far too short a period of time for effective diffusion of gases to take place. If the bubbles were fine enough for efficient gas exchange to take place, they would never reach the surface, and would never create an appreciable current.

The point to be stressed here is that whatever mechanical means of creating a water current is chosen, that current is the driving force behind efficient (as opposed to inefficient) gas exchange, which always takes place at the surface. Think about it - the deep oceans are oxygenated, yet there's no giant air stones present in the oceans! If you have any doubts that the deep oceans have a good oxygen content, check out the fish life found at the abyssal depths - there's a surprising amount of fish life even in places as deep as the Marianas Trench, the bottom of which is seven miles below the surface! However, compare that 7 mile depth with the five thousand mile width of the Pacific Ocean to which the Marianas is connected, and the ratio of surface area to depth is huge.

So, if you have a high turnover power filter creating a current in the water, the gas exchange taking place is already very efficient. In a system with filtration driven by powerheads or internal motors, an airstone is largely superfluous. Of course, the air pump and airstone are handy to have as a backup if the power filter goes down temporarily, particularly in the case of undergravel filters, but in an aquarium with a working power filter, the power filter is generating far more current than would be possible with airstones unless you filled the tank with airstones!

Again, look at the streams in which Hillstream Loaches live. The only driving force in that environment is gravity causing the water to tumble down the sides of hills and small mountains, yet that motion is sufficient for the water in those streams to be very highly oxygenated - up to saturation level. Incidentally, the definition of 'saturation level' of oxygen content of water is not fixed - it is inversely related to temperature, whereby cooler water (again, our typical hillstream full of Pseudogastromyzon Loaches) has a higher saturation point that warm waters such as those found in slow-flowing swamps in Malaysia, the home of many Labyrinth Fishes.

This is why, incidentally, long, wide, shallow aquaria are recommended for the majority of fishkeepers over tall, deep ones of the same volume - they have a greater surface area, and a greater capacity for gas exchange with or without current, and of course with a good quality power-driven filter in place, their oxygen exchange capacities are superb. Tall aquaria are recommened principally for fishes such as Angel fishes whose body morphology demands the vertical space, while for the moajority of other fishes, particularly fast swimming shoaling species such as Rummy Nosed Tetras, a long, shallow (around 12 inches depth) aquarium that has a large surface area for gas exchange (and more room for them to swim up and down the length of the aquarium to boot) is preferable.

Since you already have two power filters present, you're in a 'belt and braces' situation, where if one fails, the other can be brought into service - in which case, you are to be congratulated because you won't be caught on the hop by malfunctions unless you are extremely unlucky and both fail simultaneously, which, fingers crossed, is an extemely unlikely event with modern, high reliability kit.

Needless to say, this is a good reason to keep spares around.


Panda Catfish fan and keeper/breeder since Christmas 2002

Hmmm, thanks Cali, for explaining that better.

Excellent reply calli. I appreciate the in depth explanation. FYI, my filter is the bio-wheel variety. Kinda like a small waterfall from under the wheel. I keep my water level pretty high to reduce noise and agitation. The water falls a half inch or so. I was a bit off when describing my currents from the filter. The plants do in fact move a little bit at the bottom. My platys like to swim directly into the outlet of the filter and they have to go full speed to keep up with it. When I turn off my pump/airstone, the tank seems much more peaceful. My gut tells me that my tanks is fine with it off but now second guess myself due to the warnings of tall tanks, which I have. I may try it and view the fish's behavior throughout a 24 hour period to see how they react. I have been pretty happy simply valving the stone down as well. I did hang my pump and it is much better. It is a cheap one and may get the one you suggested considering this tank is right next to where I watch my flat screen. Thanks again.

If you're worried about the outflow being too violent, you can maintain throughput yet create less turbulent currents by directing the outflow through a spray bar - basically a flexible pipe with numerous holes in it. This will create gentler currents at one particular location, but in turn will create movement more equally distributed, thus maintaining the efficiency of gas exchange.

Your Platies are exhibiting interesting behaviour - at first, the thought occurred to me that this might be something to do with their wild behaviour - grazing algae off stones in swift moving currents. However, it transpires that Platies inhabit waters with more modest flow rates in the wild - here's the Fishbase page for the species - and so this isn't applicable here. Even so, if the outflow area near your filter boasts a healthy crop of green algae, chances are the Platies are trying to get at it, because like most popular livebearers, they eat algae as part of their natural diet. Hence the need to provide some vegetable matter for them when feeding if they don't have a great deal of algae to graze on. It's not as important with Platies as it is with Mollies, which need a reasonable amount of algae in their diet if they're going to be healthy, but cultivating some algae on some rocks for them would probably be a good idea - a trick I use with Otocinclus catfishes as well, under the heading of "Otocinclus Pet Rocks" . Basically, all you need to do is obtain a jar of approximately 1 gallon capacity, a selection of small, smooth, rounded rocks, and find a place to site the jar where it will recieve lots of natural daylight, ideally sunshine from s south facing window. Fill the jar about 1/2 full of old aquarium water from a water change, drop in the rocks, leave until they're boasting a nice coat of green fur. Then, pick one or two rocks out at a time, place in the aquarium for your algae eating fishes, exchange for more fur covered rocks when they've been scraped clean. If yu have Otocinclus catfishes or similar algae eating fishes in your aquarium, you want to see how they attack the algae with gusto once they discover the rocks!


Panda Catfish fan and keeper/breeder since Christmas 2002

Interesting. As I said, my tank is still in the cycle mode. I just started showing Nitrites about 10 days ago. Thats about when my driftwood started getting green. I see them pick at that pretty often. Is it reasonable to think that my female platty has been pregnant twice in the last 10 weeks? I never saw babies but her size sure seemed to change.

It's possible she gave birth and the fry ended up immediately as lunch for the other fishes. Depends what else is in there.

Incidentally, if you can find some Java Moss, attach it to a piece of bogwood, and let it grow, that will form a nice hiding place for future Platy babies until they're too big to be eaten, if you want to see some fry. Otherwise, you're looking at transferring her to a purpose built 'maternity ward' aquarium.

Now, you're doubtless wondering how to put one of these together. Simple!

Since Momma will be the only fish in there until she's given birth, what you need is a nice compact aquarium - a 5 gallon will do nicely. Next, you need some stiff, transparent plastic sheeting. You cut the sheeting so that you can create a V shaped cavity at the bottom, with a gap through which the fry can escape. To illustrate the kind of setup I have in mind, I've drawn a nice little schematic diagram for you in PhotoShop - see below!


Attached Image:


Panda Catfish fan and keeper/breeder since Christmas 2002