Backyard Aquaponics
A place to discuss aquaponics

I need to raise the growbeds about 10-15cm off the ground. Would cinder blocks be enough to support the weight? Or should i just get down to bunnings, get some treated pine and make my own?

Personally I would use cinder blocks for such a short lift. Even treated pine will rot with moist ground contact. Others may advise differently.

I would go with the cinder blocks (bessa blocks).

If there is even the slightest chance of water splashing off treated pine and getting into your water I wouldn't use it. Better off getting recycled hardwood from a second hand timber merchant. It is usually cheaper and IMHO safer

The weight of what? That's a piece of string question... What are your growbeds, and what are you putting in them? You will probably need both.

Sorry i will be using 6x 100L blue barrels filled with blue metal

I have cut the blue barrels half ways so i dont need the stand, where do i drill for the outlet (I was going to raise it slightly so i can drill in the bottom and the 25mm pipe can come out) if i dont raise the barrels?

You can always bring them out the side like this

Would leaving some water on the bottom be a problem (especially the top which has a rim of about 15-20mm of lid that will have stagnant water there)?

No not a problem as the beds fill and drain the water in the bottom will be exchanged

zman, still seems like you could use similar plumbing parts to make a drain centered in the bottom half of a blue barrel. Instead of elbow, use a straight piece above same parts F and F shows.

Im actually making a loop siphon from 25 mm irrigation pipe.

Would it work if the "outlet" is on the wall of the GB instead of below the GB?

Yes

Doesn't matter either way Zman... the principle that drives the siphon effect remains the same...

And, as posted... any water remaining in the bottom of the barrel will be mixed rapidly with the next fill...

My barrel system drains and fills while you stand there and watch it... over & over again....

Hi rupert do you know how big the holesaw needs to be for the 25mm ones from stacey and the 50mm hansen bulkheads?

Can i use a saw instead of a hole saw?

From memory the hole saw is 2-3mm (can't remember) larger... and no... use a hole saw...