How Big Should The Filter Be?

[Kyle Sy]

Hi,

I have a Raft type Aquaponics system. The Grow Bed can hold 3,800 litres of water and my fish tank can hold 2,000 litres of water. I just want to make sure hoe big or what requirements should my filter be?  

Is there a rule of thumb or a calculation to know this?

Thanks very much! your help and replies will be appreciated

From,

Kyle Sy

Tagaytay, Philippines

[matthew ferrell]

Are you going to to batch crops or more of a never ending conveyer?

[Kyle Sy]

We are going for batches, meaning one whole harvest at a time, did i get you right? :)

[matthew ferrell]

Yep, you want a filter that can handle the whole load then.  Go 2:1 media to tank.  If you were doing successive plants it would be different.  You do not have to run all the water through the media all the time, but i would increase the volumn towards the end of a batch. 

Actually that is really a crude answer.  What fish are you going to grow and what will be the max standing crop.  What will be the max feed rate?  Filters are properly sized that way.

[Kyle Sy]

Hi Matthew,

Thanks for your reply and suggestions!

We are growing Tilapia. We are not yet sure of our max population of the fish since we are quite new to this. But maybe you can help us determine the size of our aquarium/mechnical filter that should be placed with these details.

Fish Tank Water Max Cap: 2,000Litres (Currently at 1,200)

Grow Bed Water Max Cap: 3,800 Litres (Currently at 1,000)

Weight of FIshes as of the moment: 35kg

What would you suggest?

Thanks!

From,

Kyle

[matthew ferrell]

Okay lets say you are going to grow until a standing crop of .25lb/gal or .1lb/L which is 46grams/L. Your max fish biomass is 91 kg on fish tank water alone.  If it were me this is where I would stop, to prevent problems of overload.  If we follow this logic then you will

Max feed 1.5%bdywt/day= 1.37kilos/day
You will feed a 28-32% protein feed which will release=70 grams NH4/NH3 a day
We will assume you will be operating in temps greater than 20.  So a media filter such as beads or sand can handle about 1 gram/NH3/m2/day.  Find a media and figure out surface area, and your done.

[Jim Hebert]

Matthew, I'm a bit late, but how did you figure the 70 grams of ammonia per day?