Aquaponics Project – Some Musings.


Here is the chaos surrounding the next stage of the aquaponics project. So far, despite some time spent thinking things over, the project seems to be ‘building itself’. The benches I got some months back have worked out perfect for the job. At the time I hadn’t even thought about using them for this project but they are solid enough and have the second shelf all ready for putting the marron tanks and worm farms on.

It’s taken a little bit for me to get my head around a number of factors.

* The positioning of the grow beds on the stands and the layout of the stands. I was thinking of an L-shape but have decided that too many factors fit well if I just continue right along the house. It has meant making a slight height adjustment to allow for fitting the second shelf of the second stand into the slope of the block. Got that figured. Now I just need to cut the bench stand to fit the space and number of grow beds.

* The actual site of the grow beds. Is it sunny enough? I think it will be, last years crop of cabbage just a few metres over did fine. Is it sheltered enough? There are no tall trees to drop too much of anything and the eaves shelter the beds just enough from most of the directional rain that we get. We had a brief downpour the other day and I went out to see how much the beds are likely to collect and it will be minimal if any.

* Working with the sloping block and sinking the benches. As above but also how far from the house and how far out will the grow beds sit. Plus I figured they will be there for some time to come so I painted the wood work along the house where the stands will cover for a little extra protection. Plus I think it needed it. I treated it after we bought the house and it seemed a little neglected then and just soaked up the oil.

* Where to pump the water to and how to get the water equally through the grow beds and then draining out and getting it back into the fish tank. I have also tried to keep this simple. I was toying with the idea of automatic siphons but don’t see the point in making 8 or so siphons when the tanks can simply gravity feed the water back into the fish tank. So I am going with a simplified drainage version and plan to run the water into a main feeder pipe which will carry it back to the tank.

* The plastic grow beds took a little while to settle on too. I found some perfect black plastic boxes at the hardware store but did a little research and decided there is much, much more to plastic than I ever knew. I found the information below at this interesting site.

Types Of Plastic

In the United States, the following codes represent the seven categories of plastic used in nearly all plastic containers and product packaging:

1 - PET PET or PETE (polyethylene terephthalate) is a clear, tough polymer with exceptional gas and moisture barrier properties. PET’s ability to contain carbon dioxide (carbonation) makes it ideal for use in soft drink bottles.

Examples: Soft drink bottles, detergent bottles

2 - HDPE HDPE (high density polyethylene) is used in milk, juice and water containers in order to take advantage of its excellent protective barrier properties. Its chemical resistance properties also make it well suited for items such as containers for household chemicals and detergents. Most five gallon food buckets are made from HDPE.

Examples: Milk bottles, shopping bags

3 - V Vinyl (polyvinyl chloride, or PVC) provides excellent clarity, puncture resistance and cling. As a film, vinyl can breathe just the right amount, making it ideal for packaging fresh meats that require oxygen to ensure a bright red surface while maintaining an acceptable shelf life.

Examples: Plastic food wrap, shrink wrap, garden hoses, shoe soles

4 - LDPE LDPE (low density polyethylene) offers clarity and flexibility. It is used to make bottles that require flexibility. To take advantage of its strength and toughness in film form, it is used to produce grocery bags and garbage bags, shrink and stretch film, and coating for milk cartons.

Examples: Squeeze bottles, dry cleaning bags

5 - PP PP (polypropylene) has high tensile strength, making it ideal for use in caps and lids that have to hold tightly on to threaded openings. Because of its high melting point, polypropylene can be hot-filled with products designed to cool in bottles, including ketchup and syrup. It is also used for products that need to be incubated, such as yogurt. Many Cambo, Tupperware and Rubbermaid food storage containers are made from PP.

Examples: Bottle caps, take-out food containers, drinking straws

6 - PS PS (polystyrene), in its crystalline form, is a colorless plastic that can be clear and hard. It can also be foamed to provide exceptional insulation properties. Foamed or expanded polystyrene (EPS) is used for products such as meat trays, egg cartons and coffee cups. It is also used for packaging and protecting appliances, electronics and other sensitive products.

Examples: Plastic foam, packing peanuts, coat hangers

7 - Other Other denotes plastics made from other types of resin or from several resins mixed together. These usually cannot be recycled.

Another important type of plastic is polycarbonate, a clear shatter-resistant material used in restaurant food storage containers and the Rubbermaid Premier line of stain-resistant home food storage containers.

Why do we need different types of plastics, anyway? This excerpt from the American Plastics Council website explains it well.

“Copper, silver and aluminum are all metals, yet each has unique properties. You wouldn’t make a car out of silver or a beer can out of copper because the properties of these metals are not chemically or physically able to create the most effective final product. Likewise, while plastics are all related, each resin has attributes that make it best suited to a particular application. Plastics make this possible because as a material family they are so versatile.”

The plastic drums I have used for $25 each and actually worked out better and cheaper than the hardware store boxes I was looking at (even though they did stack neatly next to each other). The barrel drums are deep enough, made of the right plastic and will hold much more – an easy 100 litres each half. They are a No.2 on the above chart.

* I am thinking I will steady the drums by locking them in from each end by wooden posts that will be positioned for supporting climbing plants or those that may need some support. Adding some liquid nails or something to the bottom of the drum will hopefully assist with steadying them also and I am hoping that once full of expanded clay pellets they will support each other nestled together.

I think that is most of the major issues I have come across so far.

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