Pond liner thickness, bell siphon, tight outflows - beginner questions

[Louise]

Here are some more beginner's questions:

I'll be lining my grow bed in my first ever AP system with pond liner. Do you have any recommendations on the thickness of pond liner?

Any tips on how to make good, tight outflows through the liner?

I'll try to build a bell siphon like this one: https://www.youtube.com/watch?v=oDzcKgWLRf0&feature=related

Any tips or warnings?

Thank you!

Louise

[TCLynx]

John, I just sent you a private message with info on the liner if you are wanting to get a small quantity there are at least two sellers in Florida that will cut it for you.

As to the cattle panels for sides to a rectangular tank.  No I don't recommend it.  I did once try to make a "raft tank" out of cattle panels and liner.  didn't work very well.  Even after I pounded in steel fence posts every 4 feet and added wires across the top to hold the sides in from blowing out, I still wasn't terribly happy with it.

I'll have to see if I can find pictures

There is also no good way to attach the liner to the panels.

I'm working on posting about my other methods.

[TCLynx]

Ok, I know I don't have any rafts but the bed construction is the same as I would do for a raft.

Here is a picture

[John E Windsor]

Okay, no cattle panels.

Now, the rafts. I have been looking at the 2' insulation boards at Lowe's. They even offer 2' x 4' insulation boards which would mean less cutting. It is made of Expanded Polystyrene. Safe, I would assume.

[Jim Troyer]

Hi John:

The foam will work for rafts, you're gonna want 2" think as the plants get too heavy before harvest.

As far as the raft beds go the biggest thing working against you is simply the weight of water.  Water weighs 8.3 pounds per gallon; a 50 gal aquarium weighs over 400 pounds (50*8=400)  That is one of the reasons round tanks are so prevalent, the opposite sides work against each other forcing the other side to stand up ...

[Vlad Jovanovic]

John, not all polystyrene rafts are the same. Some are are considered safe, while others contain chemicals that are up for global banning…or stuff that’s on the EPA’a “Chemicals of Concern” list and are toxic to aquatic life…persistent bio-accumulative toxins…those sorts of things…

 

A manufacturer, a brand name etc…would be helpful info to confirm or deny your assumption.

(There’s not a Lowe’s within about 10,000 km from here, so I don’t really know, or care what they happen to carry)…

 

When in doubt, go with the DOW BlueBoard, as they don’t use the troublesome hexabromocyclododecane (unlike Owen Corning or Insulfoam and some others). 

[TCLynx]

Green Acre Aquaponics used to sell 2" blueboard already cut to 2' by 4' pieces.  You might contact them to see if they still carry it.  I know the 2" blueboard is usually a special order item through lowes or home depot.

[John E Windsor]

The 2" x 2' x 4' insulation boards at Lowes are Insulfoam. Now I am on the hunt for Dow. I looked at Gina's site and they don't show any in their product list.

[TCLynx]

Contact them then because on their old site they used to have it.  It won't hurt to ask and if they are not selling it, they can probably give you info on where to order it.