Backyard Aquaponics
A place to discuss aquaponics

gmturner: Thanks, IMO the winter here in Perth has been relatively mild, the tank hasn't got down to freezing yet, the temps seem to sit somewhere between 10-15 degrees, depending on the ambient temp. The tanks seems to stay at least 3-4 degrees warmer than ambient which is a nice buffer for when it does drop really low.

Mike: Hey thanks, the fitting is an eductor:

http://www.lagunakoi.com/Mixing-Eductors-Pond-Fittings-sc-149.html

Initially, it had two venturi pipes fed into the inlet stream, which pulled air in and mixed it really effectively. However, on a couple of occasions I found it had stopped pulling air in, so I don't think its reliable in that configuration. What it IS really good for is moving large volumes of water. I have it setup to circulate the water down the back of the tank, pushing solids along the base of the tank and into the SLO. It is possible to set the eductor so that the inlet stream is above the surface of the water and churning it as it enters, which would be far more reliable for aeration. At the moment, I have a air stone dangling underneath the eductor so that air is swept into the inlet stream. At some point I will get my hands in the tank and see if I can get the venturi pipes working again, water is too bloody cold at the moment!!!

Also, like many members on the forum, I have had troubles with getting my bell siphons working reliably, so I have converted to constant flow by simply removing them.

However, I have found a method which I quite like. The siphons won't start because the inflow isn't enough in some of the beds, but they will start if the bell is put back in. So, I use this to periodically siphon the contents of the beds in to the sump, which pulls A LOT of stuff out and circulates it through the system, which I can only assume helps with mineralisation. It's simply a matter of putting all 6 siphons in, allowing GB's to drain, and then taking them out again.

Perhaps a new method? Works for me....

That would explain it, i havent tested my water but it feels exactly the same as the 2.5degree chilled water room at work.

I reckon your troubles with your bell siphons might stem from the way they leave the tanks and all join into a central drain and then run to your sump, does that (80mm?) main line stay completely empty or is it always 1/3 - 1/2 full.

I find to get a bell working properly it requires quite a bit of playing with the exit piping to get it right, moreso than the actual design of the bell. If it wont start properly, add more elbows and or pipe or decrease the slope and if it wont break properly do the opposite and or improve ability of syphon to suck air at the end of cycle with a breather pipe. With your current piping you are completely stuck with what you can do.

Siphons take some trial and error. I followed to normalized sizing and they worked pretty well. Had to adjust inflow to get them to start reliably and then the horizontal pipe to get them to stop reliably. It truly is a balance and everything plays a part. You need the water in the media to move fast enough to the drain so you get a good break otherwise it gurgles and keeps from refilling.

I am inclined to agree with you both, the siphons worked flawlessly for 2-3 months then ceased to start reliably. The only variable that has changed as I see it, is the amount of solids and root material in the growbeds.

I'm inclined to think that the inflow has been slowed by this clogging and isn't enough to tip the siphons into starting. This is compounded by the shape of half barrels, as they tend to fill fast to begin with, and then slow as the area to be filled increases toward the top. I am considering incorporating a swirl filter and possibly mineralisation tank to help the beds to stay cleaner now that they have fully cycled.

The common drain is always empty as there is an open end or breather tube to stop a siphon/airlock from starting.

At some stage in the future I will look at re-plumbing the system, and upsize the PVC, but this is $$ and time. For now, I will probably modify the outlets to 2 sprinkler bar type (with taps) at each end of the GB's rather than 1 single outlet.

However, I have noticed no difference in the growth rates etc with using constant flow apart from more solids staying in the beds.

I also have some plans to incorporate strawberry towers on the frame, In which case I would probably redesign the system to be some variation on a CHOP2 pumping water up to the tops of the towers (and FT) and returning to the GB's out the bottom.

Wouldn't be any fun if it worked perfectly eh?

You might check your pipes from the pump to the grow bed. They can become lined with stuff and the effective diameter reduces and so does the flow.

The dream becomes a reality. Had these a few weeks back, stuffed with herbs, smoked over charcoal, absolutely delicious!

On another note I have added 2 dual eductors as inlets to the FT now and flow to the beds appears to have increased, which has triggered the siphons into working reliably again!

Cant wait for summer, I've already got tomatoes appearing and I'm hoping that they will grow and ripen much faster in the AP than they have in the dirt, as they usually were susceptible to attacks from pests.

Looks delicious!
Congrats on the first fish harvest!

Cheers Katmac !

Time for a show off

System is barrelling ahead after slowing down over summer and low fish stocks...restocked with 23 Silvers and system is now kicking arse...more celery than we can deal with, capsicums, 4 kinds of basil and the last tomatoes of the season coming through.

I wish I had room for more trout as I don't think we will be harvesting the silvers until this time next year, but I have plans for a second system as I picked up some BYAP growbeds for free from Cheidy;s the other day as they have a bunch of holes in them...

Hey Tristan, great system - love the central tanks with their cladding and jarrah lids and supported beds either side. Where are those strawberry towers you were planning? If you do them, just make sure they are over a growbed or some sort of drain to catch any random wicking leaks from corners of the planting holes. You don't want to lose any of that supercharged fish water.

Hey joc thanks mate, yeah I have the piping plumbed in for the strawberry towers ( you can just see the valves in the centre of the jarrah lids ) but I need to experiment with building them and also I'm concerned about loss of pump pressure to the sump

Lots of projects to get finished before then as well....

When you are ready, I have some photos of how I built mine on my system thread, but there are a few different versions of towers out there. I had to get a bigger pump once I put my towers online - just spent a good part of the afternoon trying to rebalance the system with the extra flow - enough for the towers, not too much for the FT, and just enough but not too much for the siphon in the GB... One thing I didn't take into account is that towers are great heat exchangers, so may undo all of that good insulation work you have done.

Yeah I hadn't thought of that...may be good in winter for the Silvers though.... I have been thinking of upgrading the pump size anyway, although this will mean upgrading the entire pipework... ugh

To be honest I have had the same strawberry plant in my system since I started it and I've never had a strawberry from it...I don't know if they do better in strawberry towers? I had thought the strawberry towers would look rather nice on the steel uprights

Love the look of your towers by the way, very neat! Will definitely contact you and get the low down on how to make them...

I was just reading your system thread the other day actually