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Increasing flow throughout the aquarium

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15K views 28 replies 9 participants last post by  Stan510  
#1 ·
Morning all!

So I am looking into increasing flow in my tank... As you can see in the photo I have the output flow pushing to the right of the thank and then I have a powerhead pushing the water to the left but pointing upwards to get surface agitation.. I am looking for more of a circular movement to try capture all the aquarium to get some flow.. What are your opinions and what should I change to get things working better?

Reason why I am doing this is that I am starting to get some algae and dead spots so would like to get some more flow moving..



1029062
 
#3 ·
Powerheads and wave makers. I used to use wave makers a lot in my fowlr tanks to help with dead spots. I've used powerheads in my walstad's for flow issues.

Most algae issues are more due to imbalances in ferts then flow issues. Flow issues can contribute to dead zones but spot treating those areas can help.

Is it possible there's excess dead or dying plant matter or a build up of decaying food or organics collecting in there? You may be able to get away with focusing on those areas during water changes to remove this.
 
#4 ·
Fwiw, I have found good flow to be a critical differentiator between my successful and not-so-successful high tech tanks.

I would recommend a spraybar along the back creating a nice uniform flow. Back to front, down the glass, and along the substrate into your scape.

Mmmmm yes. Loves me some good flow.
 
#5 ·
Fwiw, I have found good flow to be a critical differentiator between my successful and not-so-successful high tech tanks.

I would recommend a spraybar along the back creating a nice uniform flow. Back to front, down the glass, and along the substrate into your scape.

Mmmmm yes. Loves me some good flow.
Do you have this on your tank? If so any photos?
 
#12 ·
Over the years, I’ve played with various spraybars, powerheads and pumps (Hydor Koralia), which all work with correct directional tuning. In recent years, I’ve settled upon one spraybar that traverses the entire length (30 inches) of my tank. However, I place it in the very front of the tank, pointing down so that it sweeps the glass front, then across the substrate from front to back and up the rear of the tank.

The benefits that I find to this are:
  • With stems that reach the top, I don’t have them constantly pushed toward either the front or sides.
  • Unimpeded flow until the bottom back half of the tank is reached (main plant locations) which provides more uniform whole-tank circulation.
  • The substrate is swept with stronger circulation.
  • Aesthetically, there are no pumps, powerheads or obvious HOB-type returns in the tank.

I don’t use this for gas exchange purposes, but the water surface clearly is moving toward the front of the tank. My primary engine for gas exchange is a small, inexpensive, surface skimmer, which dramatically maximizes O2 levels (by about 50%), as indicated by a Salifert O2 test kit.

To do this spraybar, I use a small aluminum bar that sits on the top of the rim and holds the spray bar to it with small ties. The spraybar is made up of segments that insert into one another (see Amazon). In my case, I have an opaque border on the rim that completely hides the sparaybar, but the spraybar would only impact a clear rim by about ¾”.
 
#13 ·
Thanks all for your comments!

The spray bar sounds great , but that means that I need a cannister which I dot have space for. My current powerhead I believe is a bit over powered so might get a less powerful one.. From the photo I posted above how do you think I should modify it to get the best possible circulation ?
 
#14 ·
I think a 45 degree angle is the best..it sweeps over the substrate and keeps it cleanest. BUT!..the problem is if you have tall background plants? That angle will cause them to lean forward,shading the plants under them. If you don't have tall grassy plants or tall stems plants,then stick with the 45 degree's and preferably at both back corners of the aquarium.
I did notice that Amano brought that up on a Sumida video..where he tells the helper he wants the flow along the back because he does not want plants leaning forward. How true.
 
#16 ·
It might have been the front come to think of it...but for sure he wanted the return flow to go along the length of the tanks front glass. I've learned that sage advice I gave you,but also I had to break that rule when my tallest C.balansae got in the 30" range..so I had to redirect the flow along the back of the tank- leaning left or right doesn't matter much then. But,I now have to work a bit harder on getting detritus that settles in a tank with a circular pattern.
Its one of the Sumida ADA youtube vids and Amano gets kind of angry at the kid for both the direction and also because he used 3" pipe ( strong jet flow) instead of a I think 6" that made a more calm return.
If I find it later I will post.
 
#17 ·
Reason why I am doing this is that I am starting to get some algae and dead spots so would like to get some more flow moving..
I can't think of a single time I've seen increasing flow solve an algae problem. Most often it's the opposite, too much or too highly concentrated flow causing algae.

Right now your flow pattern is poor. You have your two flow sources aimed right at each other.

IMO flow is often misunderstood. People hear they need good flow and think that means plants waving around. It doesn't. You want a wide gentle laminar flow that creates a flow pattern that has purpose.

If you seek out the best planted tanks in the world, you would be surprised that most every one relies only on filter flow. You don't see extra power heads and plants waving around.

Like some others have mentioned, spray bars are excellent at producing wide gentle flow. In my tank I have spray bars aimed at an angle up to the water surface. This creates good surface ripple and oxygen levels. The flow goes across the front of the tank, down the front glass, across the substrate then back to the rear of the tank. Almost all detritus ends up along the back edge of the tank and is easy to vacuum up during a water change.

Now as to the algae you mentioned, it likely has a different cause. But that is an entirely different conversation.
 
#18 ·
Yeah I think its due to dosing Iron.. as soon as I started the staghorn appeared..

Yes its very true! I never could understand that the nicest tanks have no powerheads at all... i moved the powehead to point to the middle of the tank but still pointing up for surface agitation but not sure it thats gooe enough... do you have a pic of your setup?
 
#21 ·
Flow is good for the fish,keeps them active rather than be balloons floating in place. Not that they can't live years like that..I've seen huge public aquariums with no real flow and the big fish just...float in place. Looking depressed-lol.
Flow does do a number on BGA..but not a cure in itself.
Flow is natural..just as a fan is needed for a greenhouse or your room of houseplants as its a proven scientific fact that the movement cause the plants to strengthen..fighting off pests that thrive in stagnant air. The dopers always have those oscillating fans going for their pot.
I think its good for water plants overall..but ,many plants do just fine in still waters. Especially if you do the typicals scapers use of few and small fish. Those are the tanks where they say they go a few months with no water change. I mean how much dirt do 8 Harlequin Rasboras make in a 30 or 40 gallon, right?
 
#28 · (Edited)
I too personally am not a big fan of spraybars and pumps in my rimless tank. I have one inflow and outflow at back left hand corner and that's it. I think my turnover is only 3x or so per hour.

But it seems to work because water has no choice but to flow in one direction and that's always my answer for those who ask how to improve flow for co2 (ans: rely on the same filtration pump - with a wide dispersion nozzle (s)!).

I manage co2 by controlling injection and I even have a sump. Much easier than futzing about with powerheads imo.

And @Greggz is right that strong flow doesn't always result in effective co2 distribution. There's a whole lot of science behind it but its basically to do with the fact that Co2 is a light molecule and prefers to escape into the air so strong flow can actually just help to push it up especially if it's not co2 injected like a powerhead. Had a long discussion about this over on ukaps but I doubt I was able to convince anyone there.

Co2 is best improved through reaktors, atomisers or just diffusion in my opinion. In Hong Kong where I live nobody uses powerheads on freshwater tanks.

Here's a pic of my high tech low flow:
Image
 
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#29 ·
Flow isnt so important in plant tanks. Fish aren't even important. I've seen great tanks that were filled with fizzy bubbles- like looking at Champagne. When you add more fish..flow helps sweep up the waste that would otherwise collect on the bottom and serve as food for BGA or BBA.
Each aquarium is different, flow as needed.

I should mention that I myself am keeping fish that prefer flow. Stream fish. Barbs,Danio's,Loaches,and Rainbowfish.
No need for flow with Betta or Gourami or Angelfish keepers.