Backyard Aquaponics
A place to discuss aquaponics

Hello to all. I am working on an experimental ebb and flow system. What would be the recommended duration of the flood and the drain periods ? Thanks in advance.

Theres so many vairables i have 3 min flood and 57 min drain also another system 15 min flood and 2 hrs drain and they all grow the same

as above.

As long as the plants get wet twice a day, they dont care. It comes down to how many fish in how much water as to how often you need to flood.

More fish load = more filtration requirement = more flooding of beds, more often.

I have a 15 min flood and 1.5 hr drain, along with a 10 min flood, 15 min drain.
It really depends on your plumbing, position of growbeds, pumps, sump size, tank size, number of growbeds, personal preference, what side of the bed you wake on, state of mind etc.
Some of us do crazy things, just to see if it will work.

Ideally you would pump your entire fishtank volume per hour, for the health of your fish. So being that a GB will hold 40% of it's volume of water (once filled with gravel) just divide your tank volume by water volume in GB and then fill that many times per hour.

ie. TankVolume/(Growbed volume * 0.4)
if that comes to 3, then ideally a 20 minute cycle would be used
if it comes to 0.5 then ideally a 2 hr cycle would be used.

It is difficult to cycle too much (some plants will get wet feet) but it's disasterous to cycle not enough.
So, build your system, time the flood and drain time, then see if you can fit in enough cycles. If not add some beds.

Further to that you should have the same volume of GB(empty of gravel) to Fish tank, but that's a different topic.

When first starting up or cycling up a new system. More floods and drains per hour is better to get the bio-filter going ASAP. Then once things are well established, you can adjust the cycles to suit the fish/plants/weather.

Yep its more about bio filtering than the plants. Infact I notice plants grow better with less flooding, but when your grow bed is your bio filter you really must flood more often. How much more flooding depends on stocking density and feeding amounts; you must keep the ammonia levels down. Watch you ammonia levels and when you see more showing up then flood more often.

THANK YOU gentlemen. Now I have the idea on how to sync the cycles. Cheerz.

I was under the impression that the once-an-hour suggestion was to do with DO as well as ammonia? Is that right?

We'll be using trout so the DO is important I believe.

For trout you realy need a seperate air pump they love high do and clear water

Yes... and capture of solids and suspended matter... and really you should aim to turnover your tank capcity once an hour...

People get away with less, some drop cycles for heat retention/cooling reasons... or pump/power conservation... but IMO... depending on your fish... you're better off with regular cycles..

Dropping cycles through winter in order to retain tank temperature, doesn't compromise oxygenation as much as through summer... as the colder water holds oxygen better and may have been sufficiently oxygenated through the day... but pH plays a part in things as well..

Regardless of your cycles... IMO... supplementary aeration with an air pump is or should be mandatory... particularly with trout..

Yeaeh, sorry I left off the extra air bit