Water Usage Gauge - How Many Fish And Growbed ?

Strap a graduated rod to the siphon for checking water usage by one growbed. Alternatively you can stick a piece of plastic ruler to the side of the fish tank, don't have one at the moment. Needed to do this to find out how many growbed this single fish tank can safely support.



Below is water level just before siphon start, that mean water is full inside the growbed. It stood at about the 140 mm mark.



At siphon stop, that when you hear the burp sound is at 95 mm marking.



Subtract 95 from 140 we get 45, so its 45mm or about 1.7 inches of water used for one of this growbed. This is the easy way to determine how many growbed we can use for a given tank.

Fish tank water height is about 17 inches. 2 growbed will take about 3.5 inches, and 4 growbed will take 7 inches. I can say 4 growbed is good for this tank. This water usage is at its maximum, with time we can reduce water height in growbed. On average four growbed in this setup will use less than 25% of total water, anything less than 30% is safe.

How many fish can be in there, well what you do is measure maximum water in tank and then get the minimum reading (fill all growbed) add the two figures then devide by two, we want the average.

If average is 80 gallon, I will put 80 full grown Tilapia but if you feel its too many just reduce it by 20%

In above example with four growbed it around (17 +10) /2 , so around 13.5 inches. This we need to multiply by tank area to get volume in cubic inches and then convert to gallon.

So around 50 x 30 x 13.5 = 20250 cubic inches equivalent to about 87.5 US gallon. 

BTW, its recommended that you turn the water minimum 4 times in an hour so, if the tank capacity is 100 gallon you should total pump capacity of at least 400 Gallon or about 1500 liter per hour.

So having 2 growbed with 1500 to 2000 Liter per hour flow rate is sufficient to get this size tank cycle at minimum 4 times per hour.

15 comments:

  1. Hi Affnan,

    Could the water be turned more than or less than 4 times in an hour?

    Rgds,
    YK

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    1. If it's a large amount of water then it is ok, due to sheer volume make it impossible to turn it more than 4x in an hour. These are just rule of thumb, you would have to check on Ammonia, Nitrite and Nitrate to ensure it's within tolerable level to your fish. You would also need more aeration to top up depleted dissolved oxygen, if you see any sign of fish gulping at surface.

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  2. Good day Affnan! I am an avid reader of yours...I read your blog daily.... this is the first time i ventured into aquaponics...can i feel free to post any comment again,... salam aalaykom...i was in the in the middle east for years... and i knew a few arabic...ha...ha..ha..,,Good day to you and your family...Have a nice day!

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    1. Thanks for your comments. Sure any comments are welcome

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  3. Hello Affnan, is it ok to use polished limestone? I came across some packets at RM10 per 20Kg which is cheap compared to hydroton. Since I am just experimenting budget is tight. Thanks for sharing.

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    1. Not a problem, it is just heavy that's all.

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  4. What are the sizes of the GB and the FT - the length, breadth and the height

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  5. dear Affnan, may I know what is the suitable volume of LECA we need to support a 1 tonne water of a Fish tank?

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    1. Maximum you can go is 1000 liter of LECA.

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  6. Thank you for your reply, then what is the minimum LECA needed to support a 1 tonne water of fish tank? Because I will consider the costing, so I need to know the minimum of LECA to support my fish tank.

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  7. hi, for your calculations, (17 +10) /2. 17 is for fish tank height, what is 10 for? and why divide by 2?

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  8. hi affnan, im jsut going to start an aquaponic system in my home... but the problem is im gonna use the water from my fish pond which is quite big... and im just going to start small in the aquaponic... so is there any restriction or anything.... the thing i concern is the water ph level... and the water pump thing... is there any method to contact you privately?? have quite a lot of question to ask ask

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    1. It's not a problem to use existing pond as water source, however don't expect the aquaponics beds can do all the filtering of the pond water. You still require the existing system filter and on the pump use, it's best to use a separate pump just for aquaponics beds because it may be difficult to use existing pump.

      On water pH.. try to achieve around 6.5 to 7 it will be good for most plants and fish.

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