There are a few other DWC systems on the market and usually they are sold as part of a complete farm package. Here are a few features of other systems to watch out for and how ours compare.

The Framing System – Other DWC troughs on the market use way too much expensive metal framing and fittings then are necessary. This increases the cost and complexity of your troughs. In addition, you have to fasten the framing system together with self tapping screws which requires an impact driver and leaves metal shards everywhere.  In some DWC framing systems the sharp metal frame edges are fully exposed on the outside of the trough showing the insulation panels. This is very unsightly and you could easily cut yourself when working along side the troughs.

Growasis troughs have no sharp edges, no cutting or drilling and no visible insulation boards.

 

 

 

 

 

 

 

Raft Boards

Other DWC systems on the market require you to purchase your own insulation panels to be used as floating plant rafts. There are so many things wrong with this it’s hard to know where to start. Here’s a quick bullet list of issues.

• Manufacturers of insulation panels (like Dow) have publicly discouraged the use of insulation boards for plant or food production yet suppliers continue to promote their use.
• Pink or blue insulation boards are not ideal as they do not reflect the light back to the plants as the white boards do. There are suppliers who even recommend painting the insulation boards so they can be white. This practice is a waste of time and now you have latex paint peeling off your boards and getting into your food production system. Not good…
• When using insulation boards you have to not only cut all the boards but then you have to drill potentially thousands of little holes which creates a huge mess and is extremely labor intensive! This is arguably one of the worst things we’ve ever had to do in our early years in aquaponics. Why drill holes in insulation boards when there is an affordable food grade and pre-drilled solution already out there?

EPDM pond liner

Some suppliers also use heavy duty 45mm black EPDM pond liner for their troughs. This type of liner is extremely heavy and difficult to work with compared to the light weight 20mm structurally reinforced DuraSkrim liner. EPDM is great for lining ponds because it stretches and forms well to uneven surfaces but that feature as actually a drawback in DWC applications. Duraskrim liner is also white which is a good thing because it allows you to easily see your airstones and any accumulation of detritus in your troughs. EPDM is also a petroleum based product which is not recommended in food production applications.

Only virgin resins are used in the production of the DuraSkrim. All resins used in the food contact layer are FDA 21 CFR 177.1520 (c) 3.2 compliant.  “Dura-skrim has been approved as a material in organic farming.”

Jeff Evard
Certification Manager
Ecocert ICO LLC