System Design

If you are designing a commercial or large home aquaponices system, it will take more planning than a budget setup on the back porch.

There are several good system designs from the deep water culture raft system, like which we use,  to the vertical system promoted by Bright Agrotech, LLC, to grow beds with expanded clay media like the Bernsteins use at The Aquaponic Source.   This site is dedicated to the deep water culture with floating rafts, often called DWC.  The others have successful operations with their type of system, so you have choices to make.

Why did we choose the DWC system?  Because of the ability to have large bodies of water which is slower to temperature change.  We are in Boise, Idaho.  It gets hot in the summers and cold in the winters here.  Our aquaponics operation will be in a large insulated warehouse, as we can keep a our warehouse within a reasonable temperature range all year.

There are a list of factors that need to be carefully planned.  Some decisions will dictate options you will have available.  While others will be wide open to your creative engineering skills.  Just because someone else is doing it a certain way does not mean that is the best way or the best way for your situation. 

The reason we call it commercial is because we want to maximize the yield, both in product and in dollars.  Step back and consider all the factors before you start spending money.  This article is a guide, but there is no way we can cover every situation.  Plus will have challenges different than ours. 

Where do you want to set your system up.  We chose an insulated warehouse.  Other people have had their system in the open air on their property, or in a greenhouse.  And then there are others who have had architects design an elaborate building and system.

Regardless, at some point you will have allotted a certain amount of square footage to your system.  We would recommend trying to maximize the amount of grow space to your allotted square footage.  I would estimate your grow beds will end up taking from 60% to 65% of your total square footage.   Many design their system with less, but the more grow beds you have the more product you can grow.  Then size your fish tanks to the amount of grow beds you expect to have.  Many make the mistake of just calculating in one large fish tank.  We recommend you have at least 3 and it would be better to have four, all in one system. 

Why?  Because the output of nutrients from your system is based on the total weight of the fish you have.  When harvest time comes, if you have one tank and harvest all your fish, your available nutrients could drop as much as 95%.  That means you will be suddenly be able to grow a lot less product.  With 4 tanks, each with approximately the same size fish in that tank, you can have a tank for hatchling, a tank for small fish, a tank for medium sized fish and a tank for your large fish.   Then when you harvest, your overall system will not have such a drastic drop in nutrients.

If you click on the image below it should open in a larger window so you can see all the details.

 

Here are some ratios often quoted in aquaponics discussions.

Baby Fish

No more than 40 baby fish per 100 gallons of water.

Fish Concentrations

Up to 1 lb of fish per two gallons of water

Size of Grow Beds

For every gallon of water in your fish tank(s) you can have .5 to 1 square foot of grow beds.

Note:   Before you stock at these levels realize that these guidelines are MAXIMUMS.  You don't drive you car at the maximum speed and we don't reccommend you drive you aquaponics operation at full throttle either.  I would suggest you design your grow beds to about 75 to 80% of maximums.  Also remember it can take eleven months to fully cycle in you system.  If you try to get full production before your system is fully cycled in, your likelihood of a system crash is much higher.  If you drive your system too hard, you will need to increase your water cycles and that can create circular current in your fish tanks. which can cause slower fish growth as you have them in constant exercise.  Take it slower and build things up to a good productive state, rather than a maxed out condition.

In other words, you are not going to be able to grow 10,000 heads of lettuce a month in 500 square feet of space.  There is a definite relationship between the amount of water and fish in your system to the amount of square feet of grow beds to the amount of plants you can actually grow.  We see to common problems here and both are avoidable. 

First, it is sad to design a system then well after everything is working, to realize, that a large amount of space is wasted that could have been producing grow beds.  However you do need workroom.  Room to clean, process, package and store.

Second, designing everything maxed out, and wondering why it has problems.  Build your system in slow controllable steps up to where you are satisfied with its production.  Rather than taking maximums from a book or the internet and starting with them, design your system so that it can produce at close to maximum capacity later when you have built up the system.    

You have three things you grow and you harvest two of them; the produce and the fish.  You are also growing friendly bacteria in your bio-filters.  Your layout should take all into consideration. 

Remember, the amount of water in your fish tank(s) is a guide to determine the surface square footage of your grow beds.  Design your system so that the total surface square footage of the grow beds is for the maximum amount of fish the tanks will support in a healthy manner.  In other words our 1300 gallon fish tank, when maxed out at a healthy level will support 250 lbs to 300 lbs of fish as a logical maximum.  It will take from 4 to six weeks from start up just to establish a basic amount of friendly bacteria to support just 40 lbs of fish in our 1300 gallon fish tank.   So the commercial aquaponics layout will not use all their grow beds probably until at least 8 - 10 months of having water in your system.  If your system crashes where your bio-filters are compromised, that time will most likely be extended.