The grow beds are made with 1/4″ treated plywood sides, 2″x4″ top edge rails, and 1″x2″ untreated top edge covers. The 1″x2″s cover the edges of the pond line that is stapled into the top edge of the 2″x4″ rails.
Pond Liner Nicknames
The material I’ll refer to as pond liner has several different nicknames:
- pond liner
- water garden liner
- greenhouse cover material
- Hydroponics pond liner
- Aquaponics pond liner
- polyethylene tarp material
- UV resistant
- Fiber reinforced
- 20-23 mills thick
- One side white is best; easier to see what’s going on.
- Food Grade
Material – preferred
LDPE (Low Density Polyethylene) material.
Materials – acceptable
PVC (Poly Vinyl Chloride) pond liner is OK
PVC, PVC with internal reinforcement, and similar products
HDPE (High Density Polyethylene), but this is usually expensive. I also believe it is more ridged and harder to work with.
What to avoid
- EPDM. It out gasses toxic to system bacteria and leaches unwanted chemicals into the water
- Vinyl liner as it is too streatch
- Any product that doesn’t specifically identify what is made of.
The pond liner recommended FAP
- 23-mil P2000 by Inland Plastics Company
- 20-mil DuraSkrim R20WW by Raven Industries
Sources to obtain liners
- Green house suppliers, like those serving farmers or commercial nurseries, etc.
- Some Farm Stores
- Other Aquaponic businesses willing to sell pieces off of their large roll
- Home Depot for PVC pond liner. Don’t use the EPDM liner they sell, it’s toxic!
- Internet suppliers that sell fish pond supplies, EX: Koi ponds.
Notice that the liner in the picture above is tight/flat above and behind the bulkhead. When water is added the wrinkled part of the liner will lay smooth. This picture was taken on long grass which pushed the new liner up a couple inches.
The bulkhead has threads to allow removing the plumbing inside the tank. This makes it easy to change filters, run a fish tape down the plumbing if it gets clogged, etc.
I used PVC pond liner from Home Depot that was 7′ x 11′ in size and about $39 each. The pond liners I found were way too large physically as they would have covered 3-4 grow beds. Also the price, even though very good quality (German made) and discounted was much more than I wanted to spend, $150.
I found a couple places on the Internet that sell pond liner custom cut. They wanted $0.62/ square foot plus shipping costs.
Ex: “Custom cut liners available in widths of 10, 15, 20, 25, 30, 40 ,50 feet, and in any length to the nearest 5 foot up to 100 feet. Must be in 5 foot increments”
They often sell rubber liners. I have no clue if they will work favorabley with fish and plants.
37. “Where can I get some net pots in large quantities (5,000 pots), and some trough liner?”
69. “I purchased the 2010 Micro System DIY plans. I am having problems finding a 20 mil LDPE liner for the troughs. Homedepot has the liners but they are PVC. Will this work? Do you recommend any places that carry this material”?”