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Constant flood and drain with same water level in growbed.
http://byap.backyardmagazines.com/forum/viewtopic.php?f=14&t=25970		 Page 1 of 1
Author:  yoshisabroad [ Sep 26th, '15, 16:04 ]
Post subject:  Constant flood and drain with same water level in growbed.
Hi, I am a beginner in aquaponics, started 3 years ago. I once built small scale system nearby my window with flood and drain pipe with same water level all the time, and pump runs constantly. And I grew like leaf lettuce, mint, arugula with this system.

I do know that draining process gives oxygen to plants' roots and bacteria, that's why autosiphon is one of the most popular type.

Does the system with simple flood and drain(single pipe with media cover) make sense? Since it's constantly flowing with same water level, it doesn't bring enough oxygen to plants and bacterias. But I thought that this is easier to build and understand. I was wondering if this system is all wrong, and I should use autosiphon system.

Thanks.

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File comment: flood and drain image of the system I mean.
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Author:  Fishy John [ Oct 10th, '15, 05:01 ]
Post subject:  Re: Constant flood and drain with same water level in growbe
Hi Yoshi, its called a wicking bed, and it works well if the system you show is reversed with 1/4 water and 3/4 media. Plant your plants so just the bottom of the roots are touching the water, and the rest are in the moist media that way the air roots can breathe and the water roots can drink. Hope this helps. FishOn,FishyJohn
Author:  dlf_perth [ Oct 10th, '15, 06:45 ]
Post subject:  Re: Constant flood and drain with same water level in growbe
Quote:
Does the system with simple flood and drain(single pipe with media cover) make sense? Since it's constantly flowing with same water level, it doesn't bring enough oxygen to plants and bacterias. But I thought that this is easier to build and understand. I was wondering if this system is all wrong, and I should use autosiphon system.

yes it can work provided there is sufficient circulation around your bed.
The negative is that it always picks up water from the top not the bottom.
(but even that can be addressed)

no - you don't have to use an auto-siphon.
Many systems don't - including the basic IBC Aquaponics one
(it uses the timer method to achieve flood and drain water renewal).

the BYAP threads below cover comparisons and explanations:
viewtopic.php?f=51&t=8621
viewtopic.php?f=8&t=18956
Author:  Yavimaya [ Oct 10th, '15, 06:59 ]
Post subject:  Re: Constant flood and drain with same water level in growbe
Fishy John wrote:
Hi Yoshi, its called a wicking bed,



lol no, just no.
its not a wicking bed, what he propsed is a normal setup that is used by many.

constant flood, drop the "and drain" part mr. yoshi.

it will work just fine, as long as there are enough oxygenation points in the system then the O2 levels are more than high enough.
Author:  scotty435 [ Oct 10th, '15, 12:06 ]
Post subject:  Re: Constant flood and drain with same water level in growbe
Yes it works and it's called Constant Flood as Yavimaya mentioned. Lots of us use it :thumbright:
Author:  Stuart Chignell [ Oct 11th, '15, 03:54 ]
Post subject:  Re: Constant flood and drain with same water level in growbe
Well some of us call it constant flood and constant flow (well one of us anyway (ie me)) because the bed is constantly flooded but you also have constant flow.

As people have said it works and can work well but you have to make sure there is enough flow relative to the grow bed.

I found in my large grow beds (1m x16m) that plants did very well at the start of the bed but start to grow poorly after the first 3m. They still grew just not very well.
Author:  Yavimaya [ Oct 11th, '15, 06:50 ]
Post subject:  Re: Constant flood and drain with same water level in growbe
thats because you pumped in at one end and drained at the other.

if you spread the flow to the far and + the middle, your results would be a bit more consistent.
Author:  Stuart Chignell [ Oct 11th, '15, 07:01 ]
Post subject:  Re: Constant flood and drain with same water level in growbe
Yavimaya wrote:
thats because you pumped in at one end and drained at the other.

if you spread the flow to the far and + the middle, your results would be a bit more consistent.


Yes I know but one of the reasons I built the beds 1m x 16m was to test for scale effects and how necessary a distribution grid was.

Remember this was a design and experiment I conceived 7-8 years ago so what may seem obvious today wasn't back then.

For example back then it was being discussed whether distribution grids for FnD GBs were ncessary. The consensus was that they were. My 1m x 16m bed showed pretty conclusively that for basically all BYAP systems they were not.

However, as you say for a constant flood bed they are.

I now categorically that I don't need a distribution grid upto beds 16m long and 1m wide. The next bed I'm planing on building will be 6.8m x 17m. I'll be running trials to see how much of a grid I will need along that 6.8m width. My evidence suggests that I will need less than 7 outlets.
Author:  Yavimaya [ Oct 11th, '15, 07:22 ]
Post subject:  Re: Constant flood and drain with same water level in growbe
your 1m wide will now translate out to more like 1.5m potentially in the wider bed, but you will need to grid down some of the length too.
Author:  Stuart Chignell [ Oct 11th, '15, 07:46 ]
Post subject:  Re: Constant flood and drain with same water level in growbe
Yavimaya wrote:
your 1m wide will now translate out to more like 1.5m potentially in the wider bed, but you will need to grid down some of the length too.


Maybe and maybe. For the loads I put on the 16m bed I wouldn't for the 17m but I'm planning to increase the load to push the boundary again so yes, maybe.
Author:  Yavimaya [ Oct 11th, '15, 18:16 ]
Post subject:  Re: Constant flood and drain with same water level in growbe
well if you make the bed 6 times wider, then 6 times the load would theoretically make the same load.

i think the spread would then be 1.5m instead of 1m, roughly.
Author:  Stuart Chignell [ Oct 11th, '15, 18:49 ]
Post subject:  Re: Constant flood and drain with same water level in growbe
Yavimaya wrote:
well if you make the bed 6 times wider, then 6 times the load would theoretically make the same load.

i think the spread would then be 1.5m instead of 1m, roughly.


Yes but I wasn't talking about just increasing the total load but the relative load.
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