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Category: Aquaponics | Posted: Fri Feb 04, 2011 3:21 pm

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With the fish tank safely secured and in place, I am now into the grow beds. At first I thought that it is going to be easy until I take a closer look at the barrels that are going to converted to be the grow beds. So please lend me your minds.


Stable side ( photo / image / picture from KK Ng's Garden )
After rolling the barrel around , I found that laying it this way is the most stable. The 27cm height is more than enough for the grow bed. Laying it down this way means the opening hole will be just at 50% of the height and might be a problem for siphoning out all the water.


Concept ( photo / image / picture from KK Ng's Garden )
This is the concept and it looks simple enough but as I look at it more in detail, it becomes more complicated.

Initially I thought of using the Bell Siphon and I changed my mind because it takes up space in the grow bed. Moreover I do not want to make any hole in the grow tank because more holes means more chances of leaking. Since there is already a hole I'll make use of it the best way I can. To make use of the existing hole, I'll have to make use of the Loop Siphon which I think is possible to incorporate into the design but what would be workable and most efficient.


Design 1 ( photo / image / picture from KK Ng's Garden )
In this design, I am not sure wether the water in the 42mm chamber would be drained out or not. I have to make use of 42mm dia piping because the existing hole can fit a 42mm dia pipe snugly.


Design 2 ( photo / image / picture from KK Ng's Garden )
This might work but .......


Design 3 ( photo / image / picture from KK Ng's Garden )
This will work but I think the water in the first section of the 42mm pipe will back flow into the grow bed.


Design 4 ( photo / image / picture from KK Ng's Garden )
I like this and I think it will work. Well.....
Wanted to try it out physically but all the hardware shops are closed for the Chinese New Year break. Guess I had to wait for next week!
GONG XI FATT CAI





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Jerry Sullivan wrote on Fri Feb 04, 2011 7:02 pm:

Hi KK,

As the siphon fills up will air get trapped in the top of the 42mm segment? I don't know that much about siphon configurations to say this may be a problem. However, if it is a problem, as you test the setup, I have a couple of solutions.

Is the amount of water in the whole system approximately 200 liters? Or because of the grow tanks is the total amount of water more than 200 liters? What I'm getting at is when the power shuts off how much water returns to the fish tank?

Will the nutrient rich water go through a manifold to distribute evenly to each grow tanks?

Jerry

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KK Ng wrote on Sat Feb 05, 2011 2:29 pm:

Thanks for pointing out the possible problem about the air trap. Will let you know if it is a problem when I do the physical test and I am keeping my fingers crossed.

Good point Jerry, power cut and how much water can the fish tank accomodate. At this moment I am not able to estimate the total amount of water that will be in service until I get one grow bed up with the grow media ...... I might have to consider a holding tank huh?!

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KK Ng wrote on Sat Feb 05, 2011 2:32 pm:

Yes the nutrient rich water would be distributed evenly but I don't think that the timing would be the same. The flow would be continuous.

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Jerry Sullivan wrote on Sat Feb 05, 2011 3:13 pm:

Hi KK,
You might think about a power actuated check valve on the return. If the power fails then the valve closes and the water in the grow tanks stay put. This way you are able to have more than 200 liters in the complete system. For a recycled check valve....try a washing machine...the hot and cold water are kept in place by a power actuated valve.

Jerry

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Jerry Sullivan wrote on Sun Feb 06, 2011 6:06 am:

Suppose something happened and a grow tank leaked during the night. A shutoff float in the 200 liter tank would prevent the tank from pumping itself empty and killing the fish. There are many different ways to accomplish this.

Just thinking again,
Jerry

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Jerry Sullivan wrote on Sun Feb 06, 2011 6:20 am:

O.K One more thing and then I'm going to sleep. Since there is water and electrical power in the same location, have you thought about a ground fault outlet for the power?

Jerry

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KK Ng wrote on Tue Feb 08, 2011 2:34 pm:

Hi Jerry, thanks for your concern and tips.
A check valve on the return would definate be a must if the total water volume is more than 200 liters. In this case I would use a overflow valve instead of power actuated check valve to keep the whole design simple and minimal set up/operating cost.
I would not like to think of something happening while I am in dreamland even though it is possible ..... I guess it would then be fish for lunch and dinner.
Since the type of pump that I'll be using is the submersible, I guess the the mini circuit breaker from the power supply should suffice. I am using this same set up for the pumps in my fountain.

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