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I have 2 2217 eheim filters for my 75 gal pleco tank. Do I need to add more waterflow or is it sufficient flow with those 2 eheim's?

more specificly what kind of pleco?

I've got an inspector, but I plan on a blue eyed pleco, and a royal pleco along with a few cats/cichlids

It's hard to define "enough" here. I'm pretty sure this is "more is better" to an almost infinite extent. In one of my 100 liter tanks that have a ~1000 lph filter (Fluval 4+) and another 1200 lph "power-head", as well as sump filtration that circulates water. That is about 20x turnover, and the fish I have in there are small Panaque and some Sturisoma. The fish are all seemingly happy, the Sturisoma are breeding (although I believe a lot of fry got eaten by the Corydoras that was in there - but I've sold 19 corys, so there are no corys in there now).

But that's not the same as "these fish would be unhappy" if I lowered the flow-rate to say 5x.

--
Mats

So really how do you know enough is enough? I guess my search thru the net hasen't given me a solid definition as to what I should have in my tank. My setup includes two canister 2217's plus airstones. Would you say that, that is enough?

I personally would add more flow into the tank. Since unless you do modifications to the Eheims, the water that comes out of the spray bar loses its energy really fast.

Like Mat said, there is really never "too much flow". Get some powerheads in there. For my 20g longs, I always run at least 2 aquaclear 30 powerheads. So that about 300gph of water movement for a 20g long (not including the eheim).

Blackhawker wrote:So really how do you know enough is enough? I guess my search thru the net hasen't given me a solid definition as to what I should have in my tank. My setup includes two canister 2217's plus airstones. Would you say that, that is enough?

Well, it comes down to how you define "enough"... Enough for the fish to survive, enough for it to thrive, enough for it to be "happy" [if you can use that term]?

--
Mats

Enough to thrive and have a sparkling clean tank.

I personally would put a power head or two in there - just to make the water move a bit more.

--
Mats

on my pleco tank i have 580gph movement on the 20gallon tank. For plecos having spots where the water is really fast and spots where there is no movement is key. At times they will prefer faster movement , but when they sleep I find they enjoy a slower current.

blackhawker,

Here is the outlet I use on my Eheim 2217 filters. Far superior to spray bars. I use the 5/8 inch diameter return.
http://www.drsfostersmith.com/product/p ... catid=1313

I prefer to have at least 8 to 12 tank volumes of a filter rate gph flow rate. More is not necessary nor is a detriment. In any case their caves and your design layout should use some wood and/or rock to create some quieter zones.
In addition to the filter I recommend running one air stone. Keeping the water as close to it dissolved oxygen(DO) levels as possible for a given temperature is important and the canister filters alone do not accomplish that. The warmer the water the lower the potential DO. Most of the interesting plecos seem to be warm water species like all the Hypancistrus species to cite an example.

Superior to spray bars in that forcing the outflow into a single outlet so it is more powerful I get... but that will help the flow throughout the tank you think? (as opposed to having a spray bar turned vertically from the top to the bottom of the tank, which is what I do now)

COOL thanks apistomaster. I will attach two of those to both of my eheim's. That should help the flow be where I want it to be.

This type of outlet is better than any arrangement using a spray bar but don't forget to also use an air stone for best results.
The air stone running vigorously will both help saturate the DO levels but also sets up counter currents which will help the inlets pick up more debris from the water.
Another thing you can do where you are using 2 Eheim Classic 2217's is to run an extension tube section on one filter so that you have a strong flow exiting the outlet nearer to the bottom and the other near the surface. Just invert the "U" tube at the bottom.
All plecos like a flow across the bottom. The dual level flows plus an air stone will normally prevent the apearance of "poop" piles plecos tend to generate a fair amount of heavier waste that filters often do not efficiently remove.

there is really never "too much flow".

In many ways this is correct, but there IS a point of diminishing returns. All the motors of the filters, pumps, powerheads, etc used to get more flow are also going to raise the tank's temperature. Higher temps actually equal lower oxygen levels. I designed and built a high flow system for Chaetostoma once that I thought was perfect. My great design flaw though was that all the pumps kept the water at 85F. Much too high for Chaetostoma and actually giving me the opposite result of what I wanted since warmer water holds less O2.
This is one great point in favor of airstones (as Larry suggested) because they provide good water movement without having a motor that heats the aquarium.
-Shane

I don't keep any cool water fish so it never is an issue how warm pumps may raise the water temperature.
I was using hyperbole anyway. There are points of diminishing returns where it makes no sense to add more pumps and waste heat than you need.
I also use large wet/dry filters on my large show tanks and wet/dry filters tend to dissapate heat due to additional surface area exposed to the air through radiative and evaporation cooling.

Basically, any watt consumed will end up as heat. Having a tank with a large pump in the filter myself I know how much this heat can be. The pump consumes 38 watt, and all of this will finally be turned into heat - and the tank is 4 degrees C warmer than the kitchen it's standing in, resulting in a temp which is acceptable, but not nicely cooled.

If I had placed the pump outside of the tank (that is, dry) part of the jeat would have gone into the kitchen, thus reducing the water temp.

Still, the above mentioned dry filter is a good idea to cool water - not only because the large surface area will mean a fas approach of equilibrium, but also because a lot of water is evaporated, which reduces the temp even more - but this evaporation does have - at least potentially - have it's own disadvantages

It is another form of Murphy's law - the law of recurrent misery

To get back on topic, running two Eheim Classic 2217 with and air stone is not going to cause a water temperature increase and is perfectly adequate filtration for this 75 gal tank.

Awesome. I'm in the process of looking for a hood/light for this tank as well. What would you recommend as far as a bulb/lighting goes?

Blackhawker wrote:Awesome. I'm in the process of looking for a hood/light for this tank as well. What would you recommend as far as a bulb/lighting goes?

Lighting is for humans and plants, the fish will be perfectly fine with a very low level of lights. Plecos are nocturnal, so they come out when lights are off. You'll have more chance of seeing them if you have a less intense light.

CIchlids normally live in shady areas too, so won't want/need strong lights.

--
Mats

The new "second generation" marine circulation pumps (by manufacturers such Tunze, Vortech and Hydor), are able to shift enormous amounts of water at very low velocity, wattage and heat transfer.

With many of them, the motor is actually housed outside the aquarium. I think they are going to really catch on in the pleco hobby.

I like these Coralife Aqalights series with 2- NO T-5 lamps. They are equivalent to larger diameter lamps output despite lower wattages. Equals power savings and decent plant grow. Very stream lined designs. Available from 24 to 48 inch lengths.
http://www.thatpetplace.com/pet/prod/209809/product.web All but my 125 gal tank have these fixtures/lamps. It has HO T-5 lighting although I am only running it with one tube per fixture rather than two since all I have are some Anubias plants growing on the wood work.

Sure, plecos don't need much light but they do come from an environment subject to a night and day, Hello? Seasonal
lighting, water changes due to wet/dry seasons all factor into the breeding cycles of fish and their food base.
In the closed system that aquarium are, best we can do is simulate. We may grow plants when plants aren't native because plant life does exist whether it is simple or more complex which has positive effects on closed system water quality. I don't mind have some Hornwort or Java Moss sharing my pleco tanks nor a colony of Cherry Shrimp to assist in cleaning up bits of food beneath the notice of plecos. I strive for a modestly complex ecosystem. I even tolerate a few live black worms colonizing my thin layers of substrate. it all adds up to something greater than the individual components.

racoll wrote:The new "second generation" marine circulation pumps (by manufacturers such Tunze, Vortech and Hydor), are able to shift enormous amounts of water at very low velocity, wattage and heat transfer.

With many of them, the motor is actually housed outside the aquarium. I think they are going to really catch on in the pl*co hobby.

I bought some similar to those and had to remove them as their is no way to pre-filter and it chops up baby plecos. I don't think they will catch on.

-Trent