Backyard Aquaponics
A place to discuss aquaponics

I have been researching Aquaponics for about a month now and have gotten a lot of information on the subject. However, I have not been able to find out what the pros and cons are of both the Flood and Drain and a Constant Flow system. If anyone would be able to point me in the right direction here I would greatly appreciate it.

Depends somewhat on what you mean by "constant flow" Bfee... and what model is employed...

If you mean a continuously pumped system (like Chift Pist) delivering water to the growbeds and drained by auto-siphons.... then it's essentially flood & drain...

If you mean a constant flow... ala the UVI model...or even a system drained by overflow standpipe but continuously pumped....

Then the pre-requisite... IMO... for success... is high oxygenation, and/or solids removal....

The UVI model is highly successful... with those caveats in place... and some have had success pumping continuously into growbeds with an overflow standpipe system... again with those caveats... and often depending on the age of the system and the media depth...

Systems with small and/or shallow growbed media usually fail IMO with constant flow... as they are prone to developement of anaerobic zones and prolonged elevated nitrite levels...

They are essentially on a knife edge of imbalance... IMO..

In general, IMO.... flood & drain wins hands down in a media filled growbed model...

Flood and Drain it is than. That seems to be the general consensus. Thanks for the quick answer.

Oop looks like Rupe beat me to it.

Here is my answer assuming both options have media in the beds.
Do you mean constant flow or constantly flooded?

See you can have flood and drain even with a constant pump if you use auto siphons or some other means to manage flood and drain.

If you want to know the pros and cons between flood and drain (by whatever means) or constantly flooded beds there are many.
The main pros for constantly flooded
1-no water level fluctuation
2-perhaps somewhat more stable temperatures

Cons for constantly flooded
a- lack of aeration to plant roots causing problems with root rot or poor plant growth
b- lack of aeration to the bio-filter causing nitrite to never go to zero and other water quality issues.

Flood and drain takes care of the aeration problems very well proving good aeration to plant root zones and good aeration for the bio-filter.
Main draw back to flood and drain is the fluctuation of water levels in the fish tank or the need for a sump tank to take care of the extra water needed to flood and drain the beds. Also, when temperatures are on the extreme side, flood and drain gravel beds tend to either heat or cool the water because the air being drawn down into the grow beds on the drain cycle tends to affect the temperature of the gravel and thus the water.

We do have one member on here managing a system successfully with constantly flooded beds (Creative 1) However, that is the only one I know of that has been really successful with constantly flooded beds. I have occasionally left beds flooded for a period of time for one reason or another, I find that if I leave things flooded for a few days, I will see nitrite levels show up again if the weather is warm and fish are eating well. If you do constantly flooded, I advise adding lots of extra aeration to the system.