Fwoors Plans for a system!

[Fwoor]

So I am looking at setting up a small system and there are a few things I am looking for some advice on.

The tank is an old concrete tank in the backyard that currently has 7 or so goldfish in it. I measured it up and I would say it contains about 315L so, not huge. Tank hasnt had any feeding (beside natural) or cleaning or aeration for that matter (rain?)

I am looking at attaching two half barrels to this pond to supply some fresh veges.

One issue is that it currently has a pH around 8.4, I am assuming this is due to the old concrete leaching lime in to the water. Should I use a pH reducing media to equalize the pH lower?

I am considering using the drain pipes (autosyphon drain) as a NFT system as well as providing some much needed aeration (spray bay style). Is there any obvious flaws with this?

[Fwoor]

I've just knocked up a drawing to give you a better understanding of what I mean...

[arachdog]

Hi fwoor,

Seems like a funny place to put your pump. It will be very hard to prime in that position, and even if its self priming it will last a lot longer without large amounts of negative pressure on the suction side.
Also looking at your pictures it seems like your planning on cutting the barrel in half across its diameter, its more usual to cut them lengthwise to get more growing area.
Novel idea to put plants on you return piping. Though to be honest I'd be a little worried about the possibility of the roots blocking it up and causing a catastrophic overflow.

[Fwoor]

Hi fwoor,

Seems like a funny place to put your pump. It will be very hard to prime in that position, and even if its self priming it will last a lot longer without large amounts of negative pressure on the suction side.
Also looking at your pictures it seems like your planning on cutting the barrel in half across its diameter, its more usual to cut them lengthwise to get more growing area.
Novel idea to put plants on you return piping. Though to be honest I'd be a little worried about the possibility of the roots blocking it up and causing a catastrophic overflow.

Thanks for the pointers!

I hadnt really thought about the pump position tbh. I could just as easily go submersible I suppose.
Im thinking I can manage a failsafe, Like a piece of pipe at the top of the barrel above normal fill levels for if things go pear shaped.
I think this cut of barrel is going to work better for me given the space I have.

Actually, How do NFT systems deal with this root issue?

Cheers!

[arachdog]

Thanks for the pointers!
I hadnt really thought about the pump position tbh. I could just as easily go submersible I suppose.

No problems. You still use the external one if you want but put it at ground level then have a U-shaped piece of pipe connecting to your tank bottom. You probably will still have to prime it, but only once and the pump will operate under much less stress.

Im thinking I can manage a failsafe, Like a piece of pipe at the top of the barrel above normal fill levels for if things go pear shaped.

That sounds like a very good idea. Then make sure the plants on the return pipe will overflow into the tank, which it appears they will on your drawing, then it should all be sweet.

Actually, How do NFT systems deal with this root issue?

Just by being large enough to contain expected root growth then being properly cleaned at harvest. So if you are growing lettuce that you harvest frequently then you can get away with much small channels. Slower growing fruiting plants would require larger channels.

[arachdog]

Thanks for the pointers!
I hadnt really thought about the pump position tbh. I could just as easily go submersible I suppose.

No problems. You still use the external one if you want but put it at ground level then have a U-shaped piece of pipe connecting to your tank bottom. You probably will still have to prime it, but only once and the pump will operate under much less stress.

Im thinking I can manage a failsafe, Like a piece of pipe at the top of the barrel above normal fill levels for if things go pear shaped.

That sounds like a very good idea. Then make sure the plants on the return pipe will overflow into the tank, which it appears they will on your drawing, then it should all be sweet.

I think this cut of barrel is going to work better for me given the space I have.

OK well if you are set on that orientation I would recommend you at least cut them down smaller (like throw out the middle 1/3rd section of the barrel) because you'll find that you pump will have dramatically reduced flow if you try to pump that high, and unless your planning on growing a small tree, there's no reason for them to be so deep really.

Actually, How do NFT systems deal with this root issue?

Just by being large enough to contain expected root growth then being properly cleaned at harvest. So if you are growing lettuce that you harvest frequently then you can get away with much small channels. Slower growing fruiting plants would require larger channels.