Hypothetical system

[Eric Warwick]

As always I was thinking about aquaponics and I thought of an idea of a chift pist type system. ( or at least I think) How it works is a; gravel sump tank comes out of a overflow and goes through the entire grow bed with another overflow, then a raft system gains water from  the overflow from the sump/gravel bed and uses a water pump to go back to the fish tank through N.F.T. . If this is crazy I understand, or if this is not an original idea then good luck to the inventor. I don't have a diagram as it is just a simple not well done drawing.

[Eric Warwick]

Picture? Sorry having a hard time understanding.

TCLynx said:

A DWC beds need aeration but not necessarily their own pump.  You might have a single large blower supplying air for a large aquaponics operation but if a particular tank or bed is having extreme water level fluctuations and it is being fed by the same air pump as other tanks that are not fluctuating the amount of air flow out the various parts of the system could fluctuate in ways detrimental to other parts of the system since the valves balancing the air flow won't be getting adjusted according to the water level fluctuations.

[TCLynx]

Air will choose the path of least resistance and the shallower the water, the less resistance there is to the air bubling out the stones.  I'm not sure how to draw a picture of it.

If you have a deep tank with some air stones and a shallow bed with air stones you will need to have a valve to restrict the amount of air that goes to the shallow bed so that you can still get air to come out the stones in the deep tank.  The the water levels in the different parts of the systems is fluctuating much, the amount of air coming out the different parts is going to fluctuate too.  This might not be too big a deal if you still get enough air out all the necessary parts but if the water level gets too low in a raft bed/ sump tank you might not have any air coming out in the deep fish tank if they are both hooked to the same air pump.

[Eric Warwick]

Ok, I understand now, thank you.

TCLynx said:

Air will choose the path of least resistance and the shallower the water, the less resistance there is to the air bubling out the stones.  I'm not sure how to draw a picture of it.

[Averan]

Here's a crazy idea:

How about a Flood & Drain DWC?

Run rails under the rafts to set a minimum height, when the water in the sump-bed drains lower it will expose the wet roots to air.  When the sump floods the roots will be soaked and the rafts will be caught and floated up.  If there are no significant downsides (air temp?), this could save on aeration costs/needs!

Too crazy or just crazy enough?

[TCLynx]

Could be worth an experiment there Averan to see if it works well.

[Eric Warwick]

Actually that could work. It seems similar to an aeroponics system. What I'm thinking is just doing aeroponics with a changing amount of water, to grow potatoes. 

Averan said:

Here's a crazy idea:

How about a Flood & Drain DWC?

Run rails under the rafts to set a minimum height, when the water in the sump-bed drains lower it will expose the wet roots to air.  When the sump floods the roots will be soaked and the rafts will be caught and floated up.  If there are no significant downsides (air temp?), this could save on aeration costs/needs!

Too crazy or just crazy enough?

[Eric Warwick]

I think you should start a new discussion about this.

Averan said:

Here's a crazy idea:

How about a Flood & Drain DWC?

Run rails under the rafts to set a minimum height, when the water in the sump-bed drains lower it will expose the wet roots to air.  When the sump floods the roots will be soaked and the rafts will be caught and floated up.  If there are no significant downsides (air temp?), this could save on aeration costs/needs!

Too crazy or just crazy enough?

[Chris Smith]

Your idea will work on a small scale. If you are flooding and draining troughs you have to deal with the volume of water that is fluctuating. On a large troughs there is more water to deal with. On my 40' troughs a 1/4 inch difference in water depth can equial 100 gallons or more.
Averan said:

Here's a crazy idea:

How about a Flood & Drain DWC?

Run rails under the rafts to set a minimum height, when the water in the sump-bed drains lower it will expose the wet roots to air.  When the sump floods the roots will be soaked and the rafts will be caught and floated up.  If there are no significant downsides (air temp?), this could save on aeration costs/needs!

Too crazy or just crazy enough?

[Averan]

Just balance with media beds.  ;)

That's the last I'll distract from the OP, promise.