Aquaponics Continuous Flow Vs Flood and Drain

1. 

   simonavc New Member

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   Apr 3, 2010

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   Seems most people have flood and drain type setups.
   Is there are reason the constant flow systems are not more popular?

2. 

   Daryl New Member

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   Oct 12, 2009

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   I have run my Barra system on both flood/drain and constant flow the latter during some really hot weather in summer as it helped keep the water temp from getting to high and the only difference I found was that with constant flow the GB didn't seem to be trapping as much of the fine suspended matter in the water

3. Constant flow works fine... but you need to aerate the tank more... to compensate for the oxygenation that is acheived through flood & drain... particularly for the plant oxygen requirements....

4. 

   Murray Site Admin Staff Member

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   And, flood and drain ensures there is no tracking of water and therefore dead spots/areas in a bed.

   Continuous flow theoretically, works fine on shallow beds, say 100mm (4")
   I saw a set up recently when I was in that US run that way, 100mm deep beds with continuous flow and frankly the veggies did not look too good....ok, there could have been some other nutrient issues, but I don't think so....the fish were fine and there were plenty of them (Tilapia)
   The system had been running in excess of 6 months so nutrient should not have been an issue.

   I feel the issue in this case was poor oxygen to the roots of the plants, the beds were flooded in places showing evidence of serious tracking and the problems that brings...areas of anaerobic activity in the beds.

   This type of system can work well, but more people have more success using 300mm deep grow beds that are flood and drain. The flood and drain can be achieved by the use of auto siphons or a timer and slow drain set up. Either way works well and is well proven in the field.

5. 

   simonavc New Member

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   This is the sort of constant flow I am using.
   Not channel type system.

   The pumps are in the tanks and the pots are fed by poly rings about 250mm dia with 3mm holes every 100mm so the flow is evenly spread over the surface of the pot.
   The pots are alos up off base so no water should sit in them.

   I would have thought there would be more oxygenation this way then with flood and drain types. Huge surface area on the 200 odd litres of clay balls with constant O2 exchange (around 2000l/hour or twice system volume).

   I'll take some more close ups today, so you guys can give me some more ideas. I have made enough mistakes already.

   Attached Files:

   • 
6. 

   simonavc New Member

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   some better pics of the contrant flow pots and drainage table.
   Hope you get the idea.
   They are off my crappy iphone camera.

   Pic 4, one of the fish my mates kid gave me, forget the name, cool eh.

   The last pic is of a GP fingerling, shows the clear water in the tank (sorry about the dodgy cleaing job on the glass).

   Attached Files:

7. 

   Murray Site Admin Staff Member

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   Ok,
   The photos make a difference. Your system looks good.
   I wrongly assumed you were using traditional grow beds.
   Are you having any problems ?
   If it is working....keep on doing it that way.

8. 

   simonavc New Member

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   Just crook fish.
   See fish forum. ?Cotton wool disease.
   I've cleaned all the dead uneaten prawn off the bottom of the tanks so fingers crossed it clears up on its own.

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