Backyard Aquaponics
A place to discuss aquaponics

Would you use uniseals or bulkheads? And would you just cut out the same size hole and put everything through it?

I ask because for my 3rd system I plan on using 8'x4' growbeds but they are only 7 inches deep. So I was thinking I would build a frame using 2"x6" so that it can be 13 inches deep but I would have to use pond liner.

Thanks for any advice, my experience with AP thus far has taught me to be rather cautious when plumbing because it can be a real head ache to fix down the line :\

I would use uniseals backed by thin plywood, TC has done that before. Another option which you might not want to try is to push a pipe through a hole smaller than the pipe and clamp it with hole clamps, which is something I read on a koi forum and I'm using for small holes in liner to save on fittings. The koi folks also try to cover the hose clamps with another piece of liner as a flap of sorts, but I'd have the clamp on the outside not the inside anyway.

I've used a bulkhead fitting and its holding up fine. Get a good EPDM liner and put some padding under it (I used rockwool loft insulation) and it'll compress as you tighten the bulkhead screw.

|I would use uniseals backed by thin plywood, TC has done that before.

Dave, does that mean you would lay plywood between the liner and the growbed?

TC could tell you more because I haven't done it, but my understanding is that you need a surface to push the uniseal because you won't be able to push it through just flopping around. So the plywood works as a backing. I guess if the bed were plywood that wasn't too thick it would work for the same purpose.

i used a bulkhead fitting in my system, which is an old (full of holes ) rainwater tank and a liner the bulkhead fitting came with 2 rubber gaskets i put one on the water side of the liner and one of teh dry side of the liner between the liner and the wall of the tank, then the clamping nut on the outside of the tank to hold it steady

one tip with EPDM liner is try to make the hole just slightly smaller than you need as it stretches and still seals
but if you make it slightly to large then if it stretches ) or gets pulled while your trying to do up the nut or adjust the way the liner is sitting like it did for me ) it will leak

Cheers
pete

What is a good way to cut large round holes in the liner? Did you just use a utility knife for it?

I cut it out using the scissors on my swiss army knife (also good for pruning plants, snipping the casing off tiny seeds, and doing your toenails and bunions).

I use mine to get (cheap fla-vor-ice) popsicles open. And to remove tags from new clothes.

i used a box cutter, but scissors would be better as you have much more controll, my hole wasnt strictly round and was close to being a disaster


also just rememberd, on my GBs i used some plastic chopping boards as backing to the liner as i didnt have a hard base in them this allowed me to build a small opening under the growbed to tighten the nut or adjust/ change the tubing and check for leaks

so anything stiff would work really
Cheers
pete