pipe size for bell siphon drsains?

[Wil Miles]

Hello all first thanks to everyone who gives info we can all use it ,so does anyone know if there is a set pipe size for bell siphon drain, per gallon of water in a tank as far as drain size wise ?such as i found 1/2 inch pipe worked well to drain a 40 gallon container in less than 4 min

[TCLynx]

Bell and stand pipe size need to be tied more to the inflow rate of water to the grow bed.

[Vlad Jovanovic]

Will check these out if you haven't already...

http://affnan-aquaponics.blogspot.com/2010/02/affnans-valve-detaile...

http://affnan-aquaponics.blogspot.com/2010/05/siphon-revised.html

[Wil Miles]

still not what needed im asking the amount of water flowing in and out in two separate systems.as far as timing beteen fills and drains

in other words i have created a system that fills in roughly 10 to 15 mins and drains in 2 to 5 min

i just double drain pips size and grow bed and same time in filling and draining just curious with out all trial and error if there was a mathematical equation for it.Like in order to get this fill time and drain time you will need this size pipe with this many gallon container to get that flow     maybe im asking this wrong way ?lol

[Wil Miles]

and thanks for the reply's and yes lynx i believe you are correct that water flow is the motivator here not pipe height and yes Vlad have seen those pages but they only address the siphon start and stop but thanks for the info was always good to see  other perspective 

[David Wilcoxson]

You will not find a better article than this.  My bell siphons work perfect.  There are very easy directions to follow, and a chart describing what size bell siphon to use for different sized growing beds.  I ended up using a size smaller than recommended as the area at the end of the bed for drilling did not allow a larger size.  I just had to slow down the flow into the bed, and it works great.

http://www.ctahr.hawaii.edu/oc/freepubs/pdf/BIO-10.pdf

[TCLynx]

Wil,

    There are so many variable involved that there are few "charts" that will be very accurate.  Keep in mind as roots and stuff build up in a bed, it will change the flow of water through the media and the flow of water through the media will really affect how a bed drains.

So if you were to put a really large siphon in a bed but still use the same small media, you may find that the water in the gravel guard gets siphoned out really quick and the siphon stops while the rest of the bed is still pretty full of water.

If you are looking to run a larger bed but using the same flow of water, you will probably be stuck using the same size siphon and it will just take longer to fill and drain the bed.

Now I wouldn't get too caught up in the timing since the time it takes to fill and drain seems not to be all that important.

And in order to do what you are asking, you would need to know exact amount of water needed to fill up to the trickle over point plus the amount of water needed to trickle over at what rate before the siphon kicks in etc and you would need to be able to measure and adjust your inflow pretty exactly to balance just right with the new siphons size.  So will this really be easier than some trial and error?  In your current set up do you even know the exact rate of water flowing into your grow bed?  Have you measured it?

[Vlad Jovanovic]

TC, any one of us would be hard pressed to have the equipment and know how to measure such things...

(Not that it couldn't be rigged up, but why the hell would you want to go through the trouble)?

Mathematical models exist I'm sure, but are all but TOTALLY useless within Will's (or any of our) context.

Listen to TC Will. Trial and error and observation over time (due to some of the changes TC mentioned) are your best bet IMHO.

[Wil Miles]

yes i agree and to test the flow rate you would just use your system to fill a gallon or 5 gallon bucket and time it thats simple

and yes i agree tc you and i understand flow and root and media variables and you have answered my question the only other thing i would like to know is isnt the system made to fill in say 20 min then drain quickly stressing roots to breatha nd ready for the next intake of nuts and this is the reason everything grows so fast but is there a time limit that a bed can be filled and drained  as in how long can the roots be submerged or does that not even matter?

[Wil Miles]

hey David thanks for that info i have seen it before and i have to say like others they are trying to adjust the height of the riser pipe in reference to the bell siphon pipe which i believe doesn't matter i have a 3 inch riser with a 9 inch bell and it works fine and as far as the tubes for air to stop the flow that also is ugly unnecessary item in the smaller beds ive used largest was 2ft by 4ft long 12 inch deep not using the tubing just made the opening on the bottom of siphon 1/2 '  tall your water flow shouldn't be faster than that but again these are my opinions and by no means am expert

[TCLynx]

I've run some beds constant flood, as long as the water is well aerated and there is enough flow to keep it well circulated, most plants do just fine even in constant flood.  Some plants do even better in constant flood and a few plants would prefer more dry time.

[Wil Miles]

such as leafy plants would like raft wet all times  and say tomato or peppers like dry times?so actually the drain time is unimportant as long as your water is circulated and properly aerated i was hung up on drain times and root condition used to hydroponics root rot lol {hard to break old habits and learn new tricks}

[TCLynx]

In Aquaponics we have to keep the water very well aerated and so avoid some of the Hydro problems and I think the relative lack of mineral salts in the aquaponic water actually makes a big difference in how many plants respond to being constantly in contact with the water.

It does appear that some plants might like it better when they are getting less water time but most of them still seem to do ok even in a constant flood bed as long as the surface of the media stays dry.

It seems a common confusion that people get really tied up in drain times but there are trials going over on BYAP where they are running 3 systems.  One is constant flood, another is siphon flood and drain, and the other is timed flood and drain.  All three systems seem to be doing pretty similar.