# Water flow - the forgotten factor!



## Cavan Allen (Jul 22, 2004)

Reading gmop's thread about temperature got me thinking of other things that are frequently overlooked in terms of plant health. I can say that in my experience, it definitely does make a difference! 

Everything else being equal, a tank that has a brisk (but not overpowering) flow will do better than one that doesn't. Having a good co2 system is of little use if the carbon dioxide isn't well distributed. 

I prefer to have my spray bar at one end of the tank do that water flows the length of the tank, but I suppose you're in good shape as long as you don't end up with those dead spots. 

Temperature is definitely affected by flow too. 

Anyone care to expand on this?


----------



## stcyrwm (Apr 20, 2005)

I find my plants have been doing better with extra flow and filtration. Every time I used to work on aquariums sediment would settle on leaves and invariably if I had any fuzz algae this it where it would show up. Seems like even if I had everything else down then this would still be a problem. Now I throw the HOT Magnum on until its clear and everybody seems happier....


----------



## trenac (Jul 16, 2004)

I've found out recently that restricted water flow as a great effect on formation of algae. I installed a tank divider in my 30G tank and the side without the outlet became infested with green beard algae. However the side with the outlet had no algae, except for the greenspot on the glass.


----------



## czado (May 26, 2005)

I have never grown very straight stems, but find it interesting that even flimsier plants will grow against current. My hygro polysperma "sunset" grows near horizontally against ~25x current, for example.

I believe Diana Walstad has said that current is a benefit to natural tanks, as it helps distribute nutrients.


----------



## AaronT (Apr 26, 2004)

I have only met a few plants that prefer still water and they are all floating plants. Two I can think of off the top of my head are Lemna minor and Phyllanthus fluitans. 

Other than those two, every other plant does much better with adequate flow. I would venture a guess that the floating plants don't need the circulation because they are extracted CO2 from the air rather than the water.


----------



## freshreef (May 14, 2004)

when i started with planted tanks - most of the people told me "try to have still water, not to loose co2" , after a short period i have noticed that good filteration/water movment are doing good to my plants. 
dont try to save CO2 !!! add more water circulation n more CO2 - co2 gas is cheap !


----------



## DiPpY eGgS (Jun 3, 2005)

Great post, Cavan!
I just had a battle with fuzz algae because of sediment on the plants, and not enough flow. I lost this battle because I have been very busy lately, and didn't have time to deal with it.
THis is going to help dramatically in the future. Thanks for the insight!


----------



## Gonzofish (Mar 26, 2005)

I run a filterless 50g with only a single powerhead to circulate co2. The key is to position the outlet low to maximize circulation and minimize surface loss.


----------



## Phil Edwards (Jan 22, 2004)

Circulation is a key element of our aquaria and like Cavan said, shouldn't be overlooked or underestimated. Plants need some mechanism to transport nutrients and CO2 to them since they can't go out and get it themselves. Poor nutrient distribution can make all the difference in the world in terms of algae colonization if supplimentation and lighting are sufficient. The current doesn't have to be super strong, but it does need to be steady and strong enough to move water around the entire tank at about 5mm/sec. Try putting some finely ground flake food near the filter outlet and then follow in around the tank to see how the water moves.

I've recently had some horrible problems with a high light tank and attribute my woes to insufficient flow. In an effort to make my tank as attractive as possible I chose not to use the sprabar on my filter and got what I thought was good circulation. After a week or so things really started going downhill and BGA became a big problem. After trying all sorts of things to kill it I finally got rid of it and had a GW outbreak that wouldn't go away. By this time the plants weren't looking very healthy and I wasn't going to try a blackout for fear of killing them. After a couple weeks of GW I tore the tank down, yet again, and this time added a powerhead for CO2 distribution rather than the diffusor and added the spray bar to the filter and things have been good since. 

Regards,
Phil


----------



## plantbrain (Jan 23, 2004)

The entire flow pattern itself needs considered and mainly as a function of CO2 ditribution rather than all nutrients. If there is ample CO2, then nutrients are also distributed evenly thoughout the tank. I like the CO2 mist because I watch where the flow goes.

I use spray bars and flow patterns that go along the length of the tank and from bottom up. The CO2 rich water needs to go into the plant beds from the bottom up, not top down.

This also provides a much better place to hide the spray bar.

You'll note larger tanks have much more flow pattern issues as well as CO2 issues. This correlation is strong. Adding CO2 mist took care of two birds with one stone.

Regards, 
Tom Barr


----------



## defdac (May 10, 2004)

Here is a thesis about the subject:
"The Effects of Water Flow, pH and Nutrition on
the Growth of the Native Aquatic Plant,
Aponogeton elongatus"
http://ian.umces.edu/bill/pdfs/crossley_2002_thesis.pdf


----------



## Bert H (Mar 2, 2004)

> I use spray bars and flow patterns that go along the length of the tank and from bottom up


So Tom, you place your spray bar at the bottom of your tank? Any others do this?


----------



## JanS (Apr 14, 2004)

trenac said:


> I've found out recently that restricted water flow as a great effect on formation of algae. I installed a tank divider in my 30G tank and the side without the outlet became infested with green beard algae. However the side with the outlet had no algae, except for the greenspot on the glass.


Trena, you should post that pic. That was an excellent example of how water flow can affect a tank.


----------



## TWood (Dec 9, 2004)

Just added a separate water circulation pump that rolls the water in the tank down the front and across the gravel to a separate intake (blue line) for a canister filter in the back/bottom. The canister supply (orange line) is made to push water up through the wall of h. difformis in the pic. This, and the new UV sterilizer it runs has made for some very clean water, as well as cutting way down on green dust algae.

TW

EDIT: There's a sump for the circulation pump return, so it and the canister aren't dependent on each other.


----------



## trenac (Jul 16, 2004)

JanS said:


> Trena, you should post that pic. That was an excellent example of how water flow can affect a tank.


Here it is...


----------



## rrguymon (Jul 22, 2005)

trenac said:


> Here it is...


Wow a significant differance

Rick


----------



## zoogan (Sep 15, 2005)

*Thoday.D,Sykes.M.G (1909)*

These guys found out that not only was water and nutrients absorbed through the leaves, but water currents act as the transpiration system for aquatic plants 
. At the end of the leave there is a group of cells called blast cells that draw water through the roots and out through these blast cells.By way of water currents/movement.
Zoogan


----------

