Improving Water Flow

Terry

Member
Joined
13 Oct 2007
Messages
47
Location
Cowplain, Portsmouth
Observing some dead spots in the tank I'm looking at ways of improving the flow. The tank is 48 x 20 x 15 (inches) 250 ltr, CO2 injection, filtration is via an EHEIM 2026 Pro II. Spray bar is one the side with the holes pointing down at about 10 degress off the horizontal with the inlet pipe at the opposite end of the tank. The filter is running at about 90%.

I note in the latest edition of PFK (Back to Basics article) George recommends both inlet and outlet at the same corner of the tank to promote all-round circulation.

Does this apply only to small tanks or would it work on larger ones? The only way to find out I suppose is to try but grateful for any advice.
 

LondonDragon

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21 Feb 2008
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10,599
Location
London
You could always add a powerhead, thats what I did in mine and helped a great deal. The Koralia series look great, work very well, very quiet and low power consumption ;)
 

Themuleous

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Joined
6 Jul 2007
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4,124
Location
Aston, Oxfordshire
To add flow in my tank (120x18), I added an external eheim compact+ 3000, which can be used outside the tank. Very quite, but not cheap. This combined with the the eheim 2080 I have gives me a rated flow of 4700lph, but I only run the powerhead when the lights are on to give the fish a rest as it is mighty fast in the tank!

Sam
 

GreenNeedle

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Joined
19 Jul 2007
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2,720
Location
Lincoln UK
The reason for inlet and outlet at the same end (normally in one corner) is that the inlet is pulling water in from the bottom and the outlet is pushing water out from the top. The outlet is also pushing the water away whilst the inlet is pulling water in.

Therefore assuming you had the outlet and inlet at the left end then the water will theoretically move from left along the top of the tank and then down the right side returning along the bottom to the left side completing the 'circuit'

This of course is theoretical and there are all sorts of things like plants, hardscape that make this 'simplistic' flow change.

In a larger tank people often use 2 filters and have them set up at each end.

At the end of the day the flow should keep a lot of the 'crap' in suspension and therefore it should eventually find its way to the inflow. More important than the positioning of the inlet is the positioning of the outflow so that you can get the best circulation. Experiment with its positioning and observe the differences until you find the best position and this should also mean more particles remain in suspension.

AC
 

Terry

Member
Joined
13 Oct 2007
Messages
47
Location
Cowplain, Portsmouth
Guys,

Have made a few minor adjustments to the spraybar postioning and the inlet is now same end as the spraybar and will see what happens. The CO2 diffuser is postioned underneath the spraybar and last night most of the plants were pearling nicely.
 
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