Siphoning help needed

recampbell

So my bell siphon works great, only problem is when I set my pump on it's lowest setting when the siphon kicks in it drains fast enough so that the water level cant rise anymore so the siphon can't kick in the way and the water level remains the same and it can never fully drain the grow bed. If I turn the pump on any higher the siphon kicks in all the way but again the water level never diminishes. The standing pipe is 3/4" pvc and the Bell is 2" pvc. The soon to be fish tank is a 70 Gal tote and the grow bed is a 20 Gal flat tote. The pump is a 400 gal/hr pump, it was the only kind they had in stock. Are my proportions in correct or is my pump just to big for this set up?

arbe

Are you saying your siphon doesn't break/stop?

Charlie

Hi Recampbell :wave1:

Auto syphons can be a finicky thing, too much flow and syphon wont break, too little flow and syphon wont start.

3/4 is fairly small for a standpipe. You could try putting a 3/4 to 1" reducer on top of your standpipe, it helps speed the flow of water as it enters the standpipe and helps draw the water quickly from the media guard area and break the syphon.

Mr Damage

You need to by-pass some of the flow from the pump through a spray bar, so you can slow the in-flow into the GB and get the siphon working properly. The excess flow/pressure is run through a spray bar fitted to the top of your FT and helps aerate the water. Start with 2 or 3 x 4mm holes drilled in the spray bar.

Valves fitted to the spray bar and in-flow into the GB make fine tuning auto siphons much easier.
I would start with the valve in the in-flow to the GB fully open and the valve on the spray bar fully closed. Partially open the valve on the spray bar, wait for a couple of minutes, if the siphon doesn't stop flowing then open the valve a little more and wait another couple of minutes, repeat the process until the siphon breaks and the GB begins refilling... then don't adjust the taps any further.

If you've completely opened the spray bar valve and the in-flow to the GB hasn't slowed enough to break the siphon then slowly close the GB in-flow valve in stages (as before) until the siphon breaks. If you have to close the GB in-flow valve too far before the siphon breaks, then you will be putting excess back pressure on your pump, so you should maybe drill another hole or two in your spray bar... and start the adjustment process again.

Charlie

I think he is saying he cant find that happy medium yabbies.

recampbell wrote:

when I set my pump on it's lowest setting when the siphon kicks in it drains fast enough so that the water level cant rise anymore

and

recampbell wrote:

If I turn the pump on any higher the siphon kicks in all the way but again the water level never diminishes.

or am I reading it wrong :dontknow:

Mr Damage

Yeh, dunno Charlie... I read both those quotes as the siphon wouldn't stop flowing... whether the pump was on minimum or maximum flow... so basically the pump was too big. :dontknow:

Charlie

Yea I think your right.

hmmm, need to convert.

20Gal GB = 75L
70Gal FT = 265L
400Gal/hour = 1500L/hour

Yep, pump too big. As yabbies said, divert some water. :thumbleft:

PLJ

Great explanation and diagram, MrDamage. You have helped more then just recampbell.
Onya!

Charlie

Basically what I did with one of my old systems... spray bar to regulate pump volume to GB.

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recampbell

Wow thanks everyone! This is my first attempt and even post on an aquaponics forum and I'm astounded at the quick and helpful responses! Charlie and Mr Damages I'm going to be trying both.your ideas tonight or tomorrow and ill let you know how it goes! Thank you very much!

Charlie

Thats why this is the best AP forum around :wink:

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