Backyard Aquaponics
A place to discuss aquaponics

The more I think about constant flood, the more I realise it'd definitely be the easier way to go...wherein lies the problem. I just can't do easy!! o_O

Still toying with how I want it to run when finished and it strikes me that changing from Constant Flow/FD to constant flood, or vice versa, couldn't be too difficult...

Havn't seen that part about U bends before.. Interested to see if that works or not..

Have just lowered my sump 8" by digging it into the ground because I had to run some GB drains uphill and didn't want to do CF, so +1 on the can't do easy.. Would definately have prefered doing a U bend to shovelling dirt though..

All you have to do is take the siphon off the standpipe and keep the pump running - voila !

OK, syphon test complete. Gotta say, pretty impressed with results!

However:

(When using U-bend) Syphon will only kick in when I lift the bell about 50mm off the base of GB. I am thinking this means my bell needs to be taller, so I can get more water weight behind the u-bend. But when it goes, my God it cranks hard!

(Without U-Bend) Syphon begins with a slow trickle, but fires a few seconds later. Not quite as powerful as the U-bend set up, but still pretty impressive.

Took about half an hour to fill 300L of GB...and approx 3 mins to drain it. I didn't do a full drain with U-bend in place, but I'd wager a full 30secs to 1min faster drain would not be out of the question. It should be noted, I have not drilled any weep holes as yet. I wonder if that might help with the U-bend set up...

So it comes down to, do I want to make a new, taller, bell, or ditch the U-bend... O, lifes decisions!!

I tried that u-bend setup with one of my current bell siphons, because i've never heard of it, and yeah I couldn't get it to start up unless I lifted the bell either.. I had a fairly small bed so I let it go and it actually overflowed the bed.. After lifting the bell to get it to start, it didn't stop either, unless I lifted the bell again to break the suction..

Where'd you get the info about the u-bend? I'd give it a miss..

Just read a couple things here, actually.

viewtopic.php?f=8&t=5192&p=180907&hilit=u+bend#p180913

viewtopic.php?f=18&t=6167

...though looking at those now, I think I might have misread initially, lol! Nevermind

I have been outside playing and decided to ditch the u-bend and go with the through-the-hole method. I had decided that if it took some effort to get thing to go, it would likely take some effort to get it to stop as well. Your post has now confirmed this thought.

Need to get a pump and give this a proper shake up, very soon. Getting rather excited I am...not far off going live!

What's the consensus on these pumps?? Found at big B. Flows 8000lph (what I guesstimate would be about right for my system...) and at $49, a damn sight cheaper than a pond pump...

at a guess power consumption of over 300watts and not rated for a long life..

Cheaply made and cheap to throw out.. Expensive on the power...



Psst 8000lt is fine.. But power should be in the area of about 80-100w nothing higher..
Better to pay a little bit more up front.. and save in the long run..
[That is my think'n, I'm not sure on what other think..]

Juergen

Don't do it! Will cost you a fortune in power. I just bought a cheap ebay one then seen the calcs on a 200-300W pump power usage for the year.
Get one of these
http://www.rockaroundtheblock.com.au/product.asp?pID=913&cID=83
If you want less flow get the next one down.
Someone worked out over $400 bucks a year in power for the cheap pumps and only just over $100 for the more expensive eco type pumps

*ahem* *cough* Solar power *cough*

But yes, points noted. I did think it might be too good to be true. I'll hold off a bit and get something with a better reputation.

Back at the ranch. Aside from a few minor details - shortening stand pipes 20mm, legthening dump pipe 100mm - I am calling the construction stage of this project finished. Yay!! I have a sparky mate coming by in the next week or two to wire it all up and install weather proof GPO's and then it's just gravel, pump and fish

Pics

looks awesome !

Well done

Shame pump manufacturers don't put a power usage/head graph on the box, like they do with flow/head.
I have one of these:
http://www.walruspump.com/documentation/pw100.htm

Rated at 100W - but turned out to be 240W+ at 1M head.

The power usage should decrease with increasing head.. I think.
I might be wrong here, but I THINK this might be right....

There is more load on the motor, so flow decreases, power increases.
Even my little 32W power head was actually 38W with significantly reduced flow at 1M.
It takes 147 watts to constantly move 1 litre of water 1m vertically in 1 second, assuming no electrical losses.
Hook up a DC motor to an ammeter, let it run freely, then add some friction, amps++