# Too much current?



## Aquaticfan (Oct 30, 2011)

I have a 20 high that runs an aquaclear 50 hob filter and an aquaclear 20 powerhead. It's not to much current for that tank at all. So you should be fine. The powerhead is adjustable on its output so you can tone it down if you need to.


----------



## nalu86 (Oct 19, 2010)

I have 1700GpH in power heads + 1200GpH in filters on my 125 gallon tank  
Think I will add another 750GpH power head.

If I was you, I would add a canister with 350+GpH flow aan keep that power head, always good to have good flow to spread the nutrients and CO2 over the tank.


----------



## OVT (Nov 29, 2011)

*current vs flow*



nalu86 said:


> If I was you, I would add a canister with 350+GpH flow aan keep that power head, always good to have good flow to spread the nutrients and CO2 over the tank.


+1
The distinction between current and flow is one of the many key concepts in successfully keeping any tank. You can have too much flow (watching dwarf puffers bouncing off the walls might be fun; simulating a hurricane can be rewarding). On the other hand, you can never have too much flow. The flow is what moves stuff around in a consistent, uniform fashion throughout the tank, keeping everything inside healthy and clean.

I am also anal about keeping equipment out of the tank: I personally want to watch a fantasy landscape, not something that looks attached to a life-support system. Given that I spectacularly failed in my attempts to hide a powerhead, I do not have any in my tanks. That failure forced me to learn and to understand how to 'engineer' a tank with good flow and minimal current. You can do it too


----------



## diwu13 (Sep 20, 2011)

If your AC20 filter is on one side of the tank adding a powerhead on the other is a cost effective solution to increase the flow in your tank. So you should be fine!


----------



## Aquaticfan (Oct 30, 2011)

OVT said:


> +1
> The distinction between current and flow is one of the many key concepts in successfully keeping any tank. You can have too much flow (watching dwarf puffers bouncing off the walls might be fun; simulating a hurricane can be rewarding). On the other hand, you can never have too much flow. The flow is what moves stuff around in a consistent, uniform fashion throughout the tank, keeping everything inside healthy and clean.
> 
> I am also anal about keeping equipment out of the tank: I personally want to watch a fantasy landscape, not something that looks attached to a life-support system. Given that I spectacularly failed in my attempts to hide a powerhead, I do not have any in my tanks. That failure forced me to learn and to understand how to 'engineer' a tank with good flow and minimal current. You can do it too


Agreed. One is the difference in pressure using force. The other is about volume. In the tanks we do having volume is much more important then pressure or force.


----------



## talontsiawd (Oct 19, 2008)

HOB filters can be problematic with "force" (going off the post above) but you would have to go really big for the tank size to have too much flow (volume of turnover). I use a AC 50 and AC 20 on one of my 20L's. If I don't keep the water topped off, it will blow everything around within about 2-5 inches from the top. In a 12 in tall tank, that can be problematic. Even using a single AC 20 will blow half my plants over with just a bit of evaporation. On another 20L I have an Ehiem 2234 which probably has a lot more flow, but it is much easier to position the outlet to where I have no problem with plants. 

One tip, if you have raised lights or have the room, you get better results with the filters on the side of the tank. Some find this ugly. Even uglier, if you can put them on the sides, and the front (assuming you don't have tall plants in front), you will have less issues. That is the actual force of the filter, I don't think you have a problem with flow.


----------



## ngrubich (Nov 29, 2011)

I am also having troubles with hiding the powerhead. Would a canister filter (with a spraybar) replace the powerhead and the HOB? 
@OVT: what do you use to get a nice flow since you don't use a powerhead?


----------



## bababooey (Nov 9, 2011)

It is hard to have 'too much' _quality_ current. Ideally you want something that will provide high flow/low pressure current which is much different than the more common low flow/high pressure current found in most setups. This can be accomplished by using wavemakers and/or powerheads with good planning and layouts. This is a really amazing thread with lots of information regarding this topic.


----------



## ngrubich (Nov 29, 2011)

awesome! thanks for the link


----------



## fusiongt (Nov 7, 2011)

Dwarf puffers do not like a lot of flow so just stick with the HOB filter.


----------



## OVT (Nov 29, 2011)

ngrubich said:


> I am also having troubles with hiding the powerhead. Would a canister filter (with a spraybar) replace the powerhead and the HOB?
> @OVT: what do you use to get a nice flow since you don't use a powerhead?


@bababooey: obviously, there is more then one way to skin a cat. Different people achieve similar results with different tools for different reasons. One is not superior then others. I personally strive (not always successfully) for balance: cost vs complexity vs upkeep vs aesthetics vs ad naseum vs results. 

What does bug me is terminology like 'quality current", "high flow/low pressure current" and the like. Just to be an ass, I assert that we tend to hide behind meaningless words that do not help anyone to solve a specific problem. I call them 'meaningless" because there is a LOT more "left-out' qualifiers to definitions of "flow" and "current". If we want to be precise and explicit then we have to fall back on Fluid Dynamics, which is not something that an average person would find entertaining. No disrespect.

@ngrubich: I do not see why not, especially for a relatively small tank like your 20g. I am not a self-proclaimed 'expert': I start with the basic goal of achieving even water movement throughout the tank with minimal areas of stagnation. If you have ever played pinball or pool, you already know the principals, no need for Fluid Dynamics .

My initial thought process is based on 3 'givens": the shape and dimensions of the tank, the amount of hardscape, and the plant density/type. If the tank is over ~120g, the current experience tells me that a sump is the only viable solution for myself. Large tanks aside, here is my feeble attempt to explain myself by using my own functional tanks.

*75G Tall*: It's rectangular, it's long, it's tall. but not very deep. So, my challenge is moving a lot of water across 4' and 2' deep. This tells me that using a spray bar is a better tool then a single outlet: more water with less violence. The narrow tank becomes an advantage: I can bounce the water against one wall. But then I need it going across 4'. Solution: position the spray bar in one corner of the rear wall and the intake in the opposite corner of the same wall. Reasoning being that the spray bar pushes the water in the direction of the intake that, in turn, pulls the water. If the intake is on the opposite wall, I will end up with a dead corner across the intake. This push/pull covers the movement across the tank. What about top to bottom? I adjust the location of the spray bar vertically on the rear wall and the angle at which the water exits the spraybar holes in so that the water streams hit the opposite side in an arc. This creates spiral water movement as it keeps bouncing between two walls on it's way to the intake. Next is how close to the bottom the intake should be? About the level at which the last spiral hits the rear wall. Which usually happens at 2/3 of the tank depth. Phew. I'm 90% done.

The rest is the hard-scape: if the water spiral hits a big DW or a rock on it's way to the intake it will bounce off of it and mess up my grand design. When that happens, I re-locate the hardscape ~1/2" left or right so that is between the spirals. The last piece is the plants: putting a large sword or a hygro against the rear wall at the spot where the spiral hits will deflect the water, plant thinner, less rigid plants there instead. A single Eheim 2026 has been moving the stuff around that 75G for the last 12 years.

*12G*: long (36") but very shallow and narrow. If I use the same set-up as in 75g, the water spirals will hit the bottom, uproot plants, etc. This is a perfect case for using a singe outlet positioned parallel to the front or rear wall: the water travels along that wall, hits the opposing wall, bounces across the tank, hit the other rear/front wall. If that tank is empty, that second hit would be at ~90 degrees, resulting the water bouncing back and forth between front/back walls. Not good. Put a piece of driftwood/a stone so that it deflects the water at <~45 degrees. so that it will continue along the opposite wall. Putting the intake in the corner opposite the outfolow helps the water move along all 4 walls of the tank. Given that the tank is narrow, you do not get dead area in the center. Given that the tank is shallow, the water moves close to the substrate. Given that circular water movement along all walls tells you where NOT to put tall plants or hardscape. A single measly Finnex 360 keeps this tank healthy.

*36G Corner*: This has been my the most problem-prone tank for years. I've tried everything I could think of and tried different recommendations from others. Finally, an LFS owner gave me the solution. It does not involve powerheads, A single Eheim 2026 does the job.

There are no pictures of my 36G on this forum. The first person who comes up with the way to use a single canister filter to keep that tank running gets a 100% FREE large plant package


----------



## zachary908 (Feb 12, 2011)

OVT said:


> Finally, an LFS owner gave me the solution. It does not involve powerheads, A single Eheim 2026 does the job.
> 
> There are no pictures of my 36G on this forum. The first person who comes up with the way to use a single canister filter to keep that tank running gets a 100% FREE large plant package



Couldn't you just use a spray bar? Or perhaps split the outflow into two using lock-line?


----------



## OVT (Nov 29, 2011)

zachary908 said:


> Couldn't you just use a spray bar? Or perhaps split the outflow into two using lock-line?


Maybe. How do I get circulation into corners? 1 corner at 90 degrees and 2 at ~ 45 degrees make things 'interesting'.


----------



## Chlorophile (Aug 2, 2011)

OVT said:


> Maybe. How do I get circulation into corners? 1 corner at 90 degrees and 2 at ~ 45 degrees make things 'interesting'.


Use a T on the outflow and put two spraybars vertically in the back center with the inflow in the middle of them. Have one spraybar aimed at the left corner and one at the right corner. Flow should then sweep across the front glass where it would meet in the middle and swirl around in the middle of the tank, some of which gets sucked up the the inflow which is in the back center between the two vertical spray bars.
I can draw it if it is confusing.

The other option would be the inflow in the back center and two spray bars on one of the side panes of glass aimed straight out at the front glass. That would also create a fairly smooth whirlpool I think.

Either way the key to good circulation in the corners will be having flow sweep across the glass.
Either way there is a cushion of water in any tank in the corners that doesn't move much.


----------



## OVT (Nov 29, 2011)

Chlorophile said:


> Use a T on the outflow and put two spraybars vertically in the back center with the inflow in the middle of them. Have one spraybar aimed at the left corner and one at the right corner. Flow should then sweep across the front glass where it would meet in the middle and swirl around in the middle of the tank, some of which gets sucked up the the inflow which is in the back center between the two vertical spray bars.
> I can draw it if it is confusing.


No, you are very clear, and good thinking. You are 85% there.
Just one potential issue IMHO. <Are hints allowed?>




Chlorophile said:


> The other option would be the inflow in the back center and two spray bars on one of the side panes of glass aimed straight out at the front glass. That would also create a fairly smooth whirlpool I think.


Can you spell "whirlpool"?  o..O you did. Tried that - fish get vertigo.
Moreover, the tank is relatively high and wide. With the outflow split, the bottom ~1/3 of the tank has very little water movement.



Chlorophile said:


> Either way the key to good circulation in the corners will be having flow sweep across the (*front* - added by OVT) glass.
> Either way there is a cushion of water in any tank in the corners that doesn't move much.


+1 to the above


----------



## cdwill (Aug 1, 2010)

OVT said:


> No, you are very clear, and good thinking. You are 85% there.
> Just one potential issue IMHO. <Are hints allowed?>


Put the spraybars below the intake against the back glass, facing upward to the surface. This will create a vertical whirlpool against the back glass, eventually ripping a hole in the space-time continuum, which will suck all detritus out of the current dimension into another, dirtier dimension. Amano uses this technique.


----------



## Mathman (Apr 5, 2009)

Could you please provide a sketch or pic? Thank you.


----------



## OVT (Nov 29, 2011)

cdwill said:


> Put the spraybars below the intake against the back glass, facing upward to the surface. This will create a vertical whirlpool against the back glass, eventually ripping a hole in the space-time continuum, which will suck all detritus out of the current dimension into another, dirtier dimension. Amano uses this technique.


You made me smile: that deserves at least a +2. The idea of another dirtier 4th dimension accessible via the space-time continuum was beyond my meager spacial abilities: I have trouble with 3. (I bet that where all of my socks disappear into).

I will get back to you as soon as I find "the back glass" in a corner tank.


----------



## Aquaticfan (Oct 30, 2011)

OVT said:


> You made me smile: that deserves at least a +2. The idea of another dirtier 4th dimension accessible via the space-time continuum was beyond my meager spacial abilities: I have trouble with 3. (I bet that where all of my socks disappear into).
> 
> I will get back to you as soon as I find "the back glass" in a corner tank.


Well isnt that relative to where your standing and what direction you face? :icon_smil


----------



## OVT (Nov 29, 2011)

Please let's leave the Theory of Relativity out of this: I have enough problems as it is. 



Aquaticfan said:


> Well isnt that relative to where your standing and what direction you face? :icon_smil


----------



## bababooey (Nov 9, 2011)

OVT said:


> @bababooey: obviously, there is more then one way to skin a cat. Different people achieve similar results with different tools for different reasons. One is not superior then others. I personally strive (not always successfully) for balance: cost vs complexity vs upkeep vs aesthetics vs ad naseum vs results.
> 
> What does bug me is terminology like 'quality current", "high flow/low pressure current" and the like. Just to be an ass, I assert that we tend to hide behind meaningless words that do not help anyone to solve a specific problem. I call them 'meaningless" because there is a LOT more "left-out' qualifiers to definitions of "flow" and "current". If we want to be precise and explicit then we have to fall back on Fluid Dynamics, which is not something that an average person would find entertaining. No disrespect.


Whether you like it or not, there is a difference between 'good' and 'bad' current. You can 'not believe' that gravity exists, but that doesn't mean that you're going to fly off the ground if you stop believing it exists. The qualifiers for ideal current is pretty straight forward and easily defined. High flow/low pressure current is good, low flow/high pressure is bad. This has been proven and I've seen it first hand. 

A common complaint is 'I added a new powerhead/filter/pump and now my tank is a whirlpool!!'. Well this is often due to being misinformed by posters who insist on using 'meaningful' information while condemning logic, science, and evidence laid out by others. No disrespect.


----------



## OVT (Nov 29, 2011)

bababooey said:


> The qualifiers for ideal current is pretty straight forward and easily defined


I would really like to learn how 'good current', 'bad current', and "ideal current" are quantified. Thank you.


----------



## bababooey (Nov 9, 2011)

OVT said:


> I would really like to learn how 'good current', 'bad current', and "ideal current" are quantified. Thank you.





bababooey said:


> It is hard to have 'too much' _quality_ current. Ideally you want something that will provide high flow/low pressure current which is much different than the more common low flow/high pressure current found in most setups. This can be accomplished by using wavemakers and/or powerheads with good planning and layouts. This is a really amazing thread with lots of information regarding this topic.


Third time's the charm? As always, no disrespect.


----------



## OVT (Nov 29, 2011)

Unless that thread by Tom Barr was cited in error, it and the referenced studies have, imho, little relevance to the question at hand and no practical applications for either the OP or myself.

On a different subject, my cousin's parrot, Packitta, has a decent vocabulary. I have always wondered if he is as smart as his owners or is he just good at mimicking random sounds. My conversations with him are at least entertaining, which is a lot more then I can say of this one.


----------



## bababooey (Nov 9, 2011)

OVT said:


> Unless that thread by Tom Barr was cited in error, it and the referenced studies have, imho, little relevance to the question at hand and no practical applications for either the OP or myself.
> 
> On a different subject, my cousin's parrot, Packitta, has a decent vocabulary. I have always wondered if he is as smart as his owners or is he just good at mimicking random sounds. My conversations with him are at least entertaining, which is a lot more then I can say of this one.


Hilarious! I wonder if it takes Packitta 3 days to shoot back witty comments as well? Aw...so adorable.


----------

