The effects of Current and some new options, considerations for planted aquarist

Tom Barr

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In efforts to improve the habitats for captive livestock, and to replicate similar flow patterns found in natural systems, various "wavemakers" have been developed, marketed for the aquarium hobby. Some are rather simple. These generally have a low pressure high flow compared to the typical powerhead pumps which have high pressure and low flow.

Natural systems tend to have much higher flows and at a gentle pressure, so the first type of flow(high flow/low pressure) is ideal for our purposes. Current breaks up boundary layers they reduce nutrient and CO2 uptake in submersed plants. Additionally, good pulsed current has been demonstrated to remove up to 40-80% of epiphytes that colonize submersed leaves( Koch 1993;Hopson and Zimba, 1997; Munteanu and Manly 1981; ).
A good book web format is here:

http://books.google.com/books?hl=en...e&q=Current effects on algal epiphyte&f=false

Some discussion of light use efficacy and epiphyte modeling are discussed here:
http://wap.aslo.org/lo/toc/vol_48/issue_1_part_2/0456.pdf

It seems reasonable to me, that reduced epiphytes will obviously enhance the lower light PAR we typically provide and allow us to get the most/highest yield from the least energy from light, not to mention the aesthetics of clean leaves.

Put another way, why try and squeak out every last PAR/PUR from a light system, when some good cleaning current might offer 10-20% more growth for the same wattage you now have?

You have cleaner better growing plants, better light use, and let's not forget the main reason most of us are in this hobby: fish. Fish get much more O2 and exercise with good gentle current to swim against, they feed better, detritus is also removed and brought up into the water column where filters can remove it.

Low pressure pumps also use much less energy than high pressure systems, so the total energy required is much less than with most filters. We lack not filtration in most planted systems(the plants do a fair job of that), rather, the current is dramatically reduced through time as the plant beds form and fill in, get over grown when we often forget to prune and garden routinely.

Mixing CO2 to all regions of the tank is also much easier to accomplish. Many aquarist have used spray bars and plumbing hoses to direct current to specific spots to help achieve better mixing. These can be unsightly and complex and are still high pressure/low flow.

A good solution is available from the reef hobby using wave powerheads and timers. These cost a lot to ....relatively inexpensive. Plants and corals tend to do better with pulsed flows that are wide and low pressure, this also does not knock the fish or plants around as much.

We desire moderate even wide spread pulsed flows throughout the aquarium, not a torrent nor stagnation. Higher grade timers and more advanced systems do cost more, but offer nicer aesthetics and control variables and generally are more quiet switch on/off.

Here are some products I've been using for some time:

For smaller tanks: Rio powerheads running a long distance before hitting any plants can work rather well. A cheap strip wave timer can be used, or, if you have a advanced controller, you can use those to cycle the flow/start times, alogn with your lighting etc. Neptune, Reefkeeper etc make various controllers that have many timers built in. If you are into tech, these are likely what you might like.

Powerheads also have modification kits that convert the high pressure low flow, to high flow, low pressure:
http://www.marinedepot.com/Algae_Fr...ree_Sure_Flow_Sure_Grip-AF1551-FIPHAC-vi.html

These work quite well.

Recently, I've started using these:

http://ecotechmarine.com/

I really like these units, they cost a fair amount.
The minimal equipment inside the aquarium is attractive, no cords etc inside the aquarium, easy to use and adjust flow controller, randomizer is a nice feature.

Due to the size and design, these can be hidden easily!

The CO2 can be well mixed and get away from a mist cloudy effect, plants will pearl more vs continuous current also due to pulsed flows.

I think this, good CO2, careful even spread of light using T5's/T8's etc will really help many folks that have CO2 issues and improve fish health, reduced fish stress.

Regards,
Tom Barr
 

JDowns

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You can also use a squid aka SCWD. One input and timed dual outputs. Although for larger tanks I don't think this would work well since the amount of flow dictates the switching time. Low flow longer period of flow per output and vice versa. So for a smaller tank you can have two outputs from a canister, one on each end of the tank. This would give you a nice ebb and flow and not worry about jetting the water across the length of a tank. Only thing I wish they had was a longer time frame between switching.
 

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SCWD's and wave timers are definitely things worth a good look over. I've seen some skepticism in their application for SW reefs, but SAM's seem like very obvious candidates for this technology.

Powerheads have become my new best friend over the past months when it comes to flow distribution. It was Tom's needle wheel mod that got me into it, and now I find myself using two powerheads and a rain bar on tanks quite often. I'm considering a koralia nano for flow in my dry start tank to get more even flow.

Those VorTechs have me drooling; definitely going on the hardware list. Mrs. Philo pointed out that if you timed one of those systems right, you could create a fish sh*t tornado in the center of your tank.

-Philosophos
 

dutchy

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Tom Barr;43298 said:
Recently, I've started using these:

http://ecotechmarine.com/

I really like these units, they cost a fair amount.
The minimal equipment inside the aquarium is attractive, no cords etc inside the aquarium, easy to use and adjust flow controller, randomizer is a nice feature.

Due to the size and design, these can be hidden easily!
.

Regards,
Tom Barr

This setup is $628 here in NE, (420 Euros) :eek: That's 50% more than the US price :(
Very nice equipment though.
 

Tom Barr

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dutchy;43366 said:
This setup is $628 here in NE, (420 Euros) :eek: That's 50% more than the US price :(
Very nice equipment though.

I snagged a MP40 for 330$ USD$ new off Reefcentral.

That would run 220 euros right now or close less shipping.
Someone is making a lot of $ on imports, either that, or high import tax.

Regards,
Tom Barr
 

DukeNJ

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Interesting reading. I find it challenging to follow at times, but I'm learning.

I've been in the planted tank hobby for all of 2 months now. I've been reading much about flow, distribution, constant current promoting algae. I had the feeling that alternating currents might be a good way to mix things up. When I was younger I used to stir my coffee by stirring in one direction, then the opposite because it seemed to stir things up more than just stirring in one direction.

Seemed "stirring" might be better than blasting powerheads into deadspots. Looking for an elegant, "fewer devices in the tank solution", I ordered an Eheim 3e for the pulse function. Probably naive to think it will be adequate, but still it seemed like a good experiment to see if variable current from the filter output could kill a few birds with one stone.

Haven't installed it yet, but I really look forward to doing so now.

I was also wondering if some of the oscillating powerheads might be a poorman's solution. Two angled towards each other from some distance apart, with streams passing sometimes, colliding others might produce a nice mix of current in the aquarium. Probably too simplistic, but fun to think about. .. and another experiment to try for inexpensive options.

Wish I was more knowledgable and able to record measurable outcomes for tothers benefit.

Enjoying the site,
Duke (NJAquaBarren on TPT)
 

Tom Barr

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ddaquaria;43406 said:
Besides the randomizer, which mode is your preference for a planted tank?

Lagoon Mode seems good.

Different tanks likely will respond differently.

I'd imagine a lower light tank might do well with the lagoon, where as a dense stem plant, might do better with Reef crest. Try and see what you like.

Regards
Tom Barr
 

shoggoth43

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For the ecotech units, do you have a tank sizing recommendation? The 1500 gph on the mp10 seems to be pretty hefty for a 75 gallon tank but I can see springing for the mp20 so that you could upgrade to the mp40 later on.

Eductors seem to require a higher pressure to work relative to what most people seem to have. i.e. I don't know that an eductor gets you much, if anything, off a typical eheim type cannister. If you run an OC or Nu-Clear type cannister you probably have a hefty pump that could drive an eductor quite well, possibly multiple eductors.

-
S
 

Biollante

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Eductors Good

Hi Gilles, S, All,

I like eductors. I will grant that I tend to use pressure rated pumps, but even non-rated pumps seem to run eductors quite well.

Eductors provide wonderful mixing, large volume of non-laminar flow.

Eductors tend o provide 4 or 5 times the volume of the pumps actual flow. Most of the readily available eductors are designed for commercial mixing and like a pressure of 23 feet (10 psi) at minimum. :eek:

The eductors do what the VorTech devices or the Hydor Koralia for that matter; provide high volume at low velocity. Of course, the VorTech MP series allows pulsing and a high degree of variable flow.

Not that I would ever wish to be contentious, but I contend that the VorTech MP-10 is a bit undersized for a 75-gallon, planted tank. Given the variability of volume provided, I would think the MP-20 or 40 a better choice.

I have not used or seen the VorTech’s, but hoping some nice Loud Creature will get me a couple or six for my birthday and/or Christmas, a little hint there.:rolleyes:

Biollante
 

Tom Barr

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Gilles;43423 said:
How about eductors, did you try them are they any good?

I'll be sending a couple, then you can tell me:)
There is a trade off.

Regards,
Tom Barr
 

shoggoth43

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Good to know about the non pressure rated pumps. I've always read that the pressure rated pumps were needed to get the fullest out of them. The non pressure "should" work, and obviously do from what you say, but I would imagine the flow is quite a bit more anemic because of it.

The obvious trade off would be velocity for mass. More flow in the tank for less speed. Pressure should help keep the speed up a bit if that's what you need/want.

-
S

Biollante;43612 said:
Hi Gilles, S, All,

I like eductors. I will grant that I tend to use pressure rated pumps, but even non-rated pumps seem to run eductors quite well.

Eductors provide wonderful mixing, large volume of non-laminar flow.

Eductors tend o provide 4 or 5 times the volume of the pumps actual flow. Most of the readily available eductors are designed for commercial mixing and like a pressure of 23 feet (10 psi) at minimum. :eek:

The eductors do what the VorTech devices or the Hydor Koralia for that matter; provide high volume at low velocity. Of course, the VorTech MP series allows pulsing and a high degree of variable flow.

Not that I would ever wish to be contentious, but I contend that the VorTech MP-10 is a bit undersized for a 75-gallon, planted tank. Given the variability of volume provided, I would think the MP-20 or 40 a better choice.

I have not used or seen the VorTech’s, but hoping some nice Loud Creature will get me a couple or six for my birthday and/or Christmas, a little hint there.:rolleyes:

Biollante
 

Tom Barr

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But we do not desire speed and fish blasted and plants blasted to the walls.

We desire good high volume gentle currents, slower speeds.
This yields better growth rates in natural systems, higher rates decrease plant growth or scours them out on the other hand.

So these type of pumps, (boat propellers) give the best type of flows, not high pressure. They also use much less energy for the same volume(but the trade off is very low pressure). Since we do not need to pump against a head pressure, this makes a lot more sense to use from a engineering/efficiency standpoint.

Regards,
Tom Barr
 

shoggoth43

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trade offs

I'm all for flow rates and needle wheel CO2 injection but I'm with you in thinking the plants and fish would be happier not living in the whirlpool tub. :) I was thinking of velocity from an eheim equipped eductor being a couple inches per second vs. maybe 12-16" per second with a pressure pump which doesn't seem out of line compared to what a vortec can do based on the videos I've seen.

So from an efficiency/flow standpoint, is it better to shove an eductor on an existing outflow from a cannister like an eheim or are we better off with a prop pump? How does this change if one uses a pressure pump? Does the eductor affect power usage by adding head pressure to the pump and will this pressure affect the power usage of a pressure rated pump all that much?

I think you mentioned at one point going back and using a sump and then vortec pumps in the tank. Do you expect that to be more or less efficient overall since you'll be pumping up 4 feet or more head pressure compared to the minimal net head pressure of an eheim type cannister? I think the MJU pumps would be fine for something like that and draw in the 60-100W range so that seems high compared to an 30-40W eheim but they'll push a lot more water to start with and I guess it depends on how many cannister filters you used.

Sorry for the rambling, I'm just trying to get a better idea for really good flow with least wattage and prop pumps do seem like they're currently where it's at.

-
S

Tom Barr;43661 said:
But we do not desire speed and fish blasted and plants blasted to the walls.

We desire good high volume gentle currents, slower speeds.
This yields better growth rates in natural systems, higher rates decrease plant growth or scours them out on the other hand.

So these type of pumps, (boat propellers) give the best type of flows, not high pressure. They also use much less energy for the same volume(but the trade off is very low pressure). Since we do not need to pump against a head pressure, this makes a lot more sense to use from a engineering/efficiency standpoint.

Regards,
Tom Barr
 

Biollante

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Eductors Experiment

Hi All,

I think the problem with the non-rated pumps is a reduced ‘fan’ as well as volume and the eductors do I believe (my observation, all, may be another of my many bad conclusions) they create a backpressure that could be a problem for some non-rated pumps.

The relatively gentle, wide flow seems to be a real plus.

(Without arguing, the accuracy and I concede my experience is not to replace lab quality everything.)

One thing I have noticed using my little CO2 test gadget-probe thing is that the CO2 gradient is relatively high from bottom to top of water column at the front of the tank and lower in among the plants. I have found that the eductors tend to mix that higher CO2 water and distribute it to the center.

I am experimenting with an eductor (from a water bed fill kit) to pump from a front corner, piping under into a the center of a group of plants, distributed via a pvc tube with some holes drilled along the length.

(Please read disclaimer, I am not trying to offend anyone.) :eek:

Biollante
 

Tom Barr

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The educators have a much lower total volume running through the orifice due to higher pressure and smaller outlet. This intense pressure pulls in surrounding water.

The surrounding water is what causes the higher flow, not water through the pipes/filter etc.

If you have head pressure to burn.......then sure.
But that cost more $, energy, louder pumps etc.

I think it's better, more efficient to use a supplemental powerhead.
You get more flow, less noise, less expense, less energy

Regards,
Tom Barr
 

Biollante

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Trade Offs

Hi All,

Yes everything can be done with powerheads and so forth; I never suggested eductors replace other means. :) Just as powerheads do not add anything to the flow through the pumps the eductor simply uses kinetic energy to propel the water rather than an impeller or propeller. :)

I am not trying to offend, a question was asked, my opinion, carries no weight, requires no action of anyone.

Though for some the price of the alternatives are extreme. For the price of one of those VorTech’s a person might, could, maybe find a pretty good used or rebuilt pressure-rated pump, plumbing and an eductor or six. ;)

If someone is using power rated pumps, often cheaper, quieter and more efficient (in my experience, anyway) in the long run, then eductors, in particular some of the commercial mixing and pumping eductors, can make a system more efficient and increase the effectiveness of existing pumps.

Life and this hobby are trade-offs.

Eductors, into the off-limits bucket.

Biollante
 

Tom Barr

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Well, they can be tried and see how they work, but overall, they have a bad trade off by reducing the flow through the pump system.

If you cannot add any more powerheads, wave makers etc, then it might not be a bad idea, or you have some head pressure to burn.

Reef folks might, plant folks rarely do.

Regards,
Tom Barr
 

Gilles

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Well the problem i have is that all my returns are placed inside my DIY rock wall. So i can't place a MP20 in there..