Backyard Aquaponics
A place to discuss aquaponics

So as our trial into AP, we've made a small fish tank 3.0mx1.0mx0.5m (holds 1500l if my math is correct) we researched that we should have about 5sqm of 300mm deep GB's, first of all is that about the right balance?

I figured the easiest way to do it was a continuous flow system, pump from the fish tank into the GB's and let it filter back into the fish tank. Fish tank is on ground and GB's will over hang part of fish tank to allow draining of GB directly into fish tank.

Burnsy mentioned the use of a bell siphon, I did a search and read a few posts on them, came across a rather descriptive post on them by 'Ell' is it? Well I can't find the bleeding thing now and I dunno if I'm just dumb or sucha newb, but I can't quite grasp the make-up of a bell siphon. Do I need one?

Oh crud, past midnight off to bed will add more - hopefully pics tomorrow, I mean later today!

Hehe You are going to dream of them ALL night tonight

A siphon that works well will empty the growbed of water faster than the water comes in. The growbed fills to a set water depth (less than the gravel depth) and empties out.
The water needs to leave the grow bed so the roots get air. This is the reason for the siphon.

The bell siphon design is simple and adjustable yet stable. A loop is easy to learn to set up but it may move around more.

Here is Ell's famous siphon discussion:
viewtopic.php?f=8&t=685

Did I get it pretty much right?

Rick

http://backyardaquaponics.com/forum/viewtopic.php?f=8&t=685

oops, some one beat me to it.

Loop siphons are probably easier to set up if you don't have power tools to cut the PVC for the crenelations. Loop siphons though can have issues with the flexible tubing flatting out over time if not sturdy enough or supported well enough. It may also be easier to modify bell siphons to cope with slightly less than perfect flow rates with the use of breather tubes and such.

Either work so long as you size them appropriate to the inflow to the beds.

I like to experiment with my system... currently, I have 3 bell siphons, 1 loop siphon, and 2 "flushers": viewtopic.php?f=18&t=5098&st=0&sk=t&sd=a&start=15

All the beds are in a sequencing valve that fill each bet once every 90 minutes.

My observations on these:
--Loop siphon works well, but you need to make sure you have enough water pumping in to get it going. It's also easy to adjust the flood height. I also installed a small weep hole in the GB to drain any extra water out that is trapped in the GB after the siphon breaks (during the off-cycle of the sequencing valve.
--Bell siphon also works well, a major plus is that it's inside the bed. I also have a weep hole in the standpipe to let the excess water out during the off-cycle. It's slightly more difficult to adjust the flood height, but I've made minor adjustments to the standpipe height to fine tune the flood height. If made properly, you can have a very slow flood/fill rate and it will still work fairly well
--"flusher" also is a champ. It's external to the GB but allows me to adjust the height easier than a bell siphon. It also work great with very slow fill rates...(I like to use cheap little pumps that consume very little power)

The other option is the Flout, which some people use...they work very well too. For a beginner, I would go with a loop.....

While syphons look great and work well in theory, they can be a bugger to setup so they run 24/7 without intervention. From experience for a first timer, I would run a flood and drain system with a timer - 15on / 45 off. Keep it simple until you get the hang of it and then start experimenting.

cheers
Derek

Thanks everyone. I think I'll stay away from a bell siphon for the mo, it's only a test for us to begin with, to see how everything works.

I can't remember where I saw it (I've looked at so much stuff online it seems to be a bit of a muddle) but I was thinking of having a continuous flow system, is there a problem with that?

We are doing everything budget (low budget) for this system - I suppose 'cause we don't have any money:) and I revived an old water feature pump, not sure what it's specs are for l/hr or max head etc, but to save initial outlay we wanted to use this little guy. Down the track I think a bigger pump and more sophisticated system might be in the wind.

What I'm concerned about is I've seen a continuous flow type system, but a whole heap of people use flood and drain, is it just personal preference?

I figure the continuous flow is simple enough, leave the pump on, let the water trickle through GB's and it comes back to fish to go around again. Is there anything specific I need to watch/ design for?

The boss wants to use blue stone gravel about 10mm in size I think ('cause we got it here already) do we have to use that orange looking clay stuff?

I'm making my grow beds 300mm deep, that's about right? and just to clarify once we are running at warp factor 9 we should have about the same volume of GB's as in the FT?

I'll try to get some pics of what we've done so far and put them up, thanks again all

Generally I'd think that 10mm might be too small... for flood and drain... with continuous flow... probably even more so...

The smaller media size and lower flow of a continuous flow system might result in clogging of the media...

10mm would certainly be the minimum size for flood & drain IMO... and a bigger size would be preferable

Sigidi

I have a simple flood and drain system with gravity return and use washed 20mm drainage gravel in most of my growbeds but I do have 10mm in some and they perform no differently. You're welcome to visit if ever you're passing through Brisbane northside. You can give me some tips on sharpening my chainsaw Just PM here or through the other forum if you're interested.

cheers
Derek

Derek, well there ya go, I've seen posts of yours on this forum and never even associated you with sawmilling - blinkers on with AP:)

Thanks for the offer, I'll surely take you up on it when I'm down that way.

Allan

So does everyone use the hydrated clay 'cause it's lighter in the GB? Is gravel okay, or do I need to adjust the height of the water to account for less 'moisture holding' by the stones?

When you first plant, do you need to have the water level up higher as the plants are new? I have it at around 40mm deep on continuous flow.

Gotta get pics from wifey's computer...

and how do folkes go with 'solar heating' the FT via pipe on the roof. I have a lot of available roof space and if possible would like to have fish growth all year - my water is around 16 deg and as I'm very partial to SP, I'd like to get it up 4 deg.

At the mo we have about 70 fish in there, just to see how things go, got 'em free, so if we've drastically buggered up, then it's not a massive loss, but still devastating nonetheless...

Any washed stone is fine as long as it is inert so it does not change the pH. At school I have beds of gravel, bluemetal and expanded clay so the kids can do comparisons. I like the washed pea gravel better than the expanded clay as it holds the big plants up better. Bluemetal hurts my soft timber millers hands when I am planting seedlings into it

Washed gravel with 50mm of expanded clay on top like some guys have would be great, but the expanded clay is expensive so it won't happen at home for me.

Not sure of the continuous flow level recommendation, not familiar with it.

So this is how the system is looking so far, we had a weekend putting things together. I was talking to our two youngest 6 and 10 on the Saturday, asking them "what's today?" and bless her cotton socks, our 6 yo said "Aquaponics day!"

Well it's gone on for a bit more than a day... but this is the area of 'dead space' we are looking at setting up the first system.

This was me preparing the area a bit, nothing extreme, just a touch of cut and fill and removing the few bits of grass.



Then we began making the fish tank... now I know for most of you the images which come to mind when hearing the comment 'making the fish tank' may not be what I'm about to show...



So basically the tank is to be four layers of 6x2 good old Aussie hardwood. The tank overall size is to be 3x1x0.6m with the water only being 500mm deep.