Backyard Aquaponics
A place to discuss aquaponics

I dug some gravel out of my beds which are coming on 4 months old and put it into my pot over top of my aquarium. Then ran the powerhead water to the pot of gravel within 10 seconds I couldn't see a single fish in the aquarium. My system tanks are crystal clear. Light tea colour if anything, but crystal clear. The gravel does an amzing filtering job.

Having the water enter and exit the same port has its problems with solids getting washed back into the water, but I think that the initial question was whether or not you could just dump the water in at one place in the GB, versus attempting to evenly distribute it across the entire surface.
I will be happy to defer to the experts on this, but my speculation would be that as long as there is some distance between the points, in a flood & Drain system, it shouldn't make much difference. For example, if you dump your water in on one end of the bed, and drain it from the other, you should be fine. The solids would be filtered through the length of the bed, and the nutrients would be disolved in the water.

I needed to re-work one bed to get the Duckweed Detour going. The end result is that I have one bed that dumps all the water in at one spot. I figure that means the earthworms know where to come for dinner. It also means that all the cat hair accumulates in one spot and is easy to pick off the surface. As I have reason to re-work the other beds, I will probably do the same thing instead of re-constructing more grid distribution lines.

Hi,

Greenedo......you're right, the discussion started out with the notion of avoiding the distribution grid.....with a view to reducing the amount of pipework in the grow bed. I took it one step further and suggested that the water enter.....and leave......by the same pipe, further reducing the complexity of the system.

I'm beginning to accept the notion that "fines" may discolour the water in such a situation. I certainly acknowledge that such fine sediment exists because I get it in my bio-filters.

The outlets on my bio-filters are several inches from the bottom of the drum. It's the same with my gravel/expanded clay grow bed.....the outlet is in the side rather than the bottom of the bed. In both cases, there is always some water left in the container.

When I clean out a bio-filter, I simply turn the drum to allow me to put a bucket under the outflow and tilt it until all of the sediment runs out of the water space that is normally below the outflow.

I've noticed that, as fine as it is, the sediment settles out very quickly once the water becomes still.

I wonder if the solution may not be to locate the entry/exit line in the side of the tank rather than in the bottom......leaving somewhere for the sediment to gravitate out. A drain installed in the bottom of the tank would then allow period removal of surplus sediment by flooding it up and then dumping it straight onto a garden bed or (better still) into your worm beds.

Having said all of that, having the inflow and outflow at opposit ends of the bed is a similarly simple alternative to the sophisticated and costly distribution pipework that is evident in some members' systems.

Gary

There are many different ways of distributing the water to your growbed, and many factors to consider. Aniother factor to considr when planning your irrigation of the bed is water flow. My pumps are fairly large and although I have a lot of piping on the growbeds with many holes in them, every hole has water coming out when the pump is on.

Personally I wouldn't recommend only having one point of water entry into your growbed, if it's a large growbed, due to the possible build up of solids in the one spot.

oops, probably should have clarified, i have one bath tub as the growbed

I am with you

OK so now we have got the irrigation piping set up on the system and for the first time have cycled the water through. It takes 6 minutes to fill the grow beds.

Each grow bed is 1750 diameter, 350deep and it takes 1 hr to drain out using two 6mm holes.

Is this drain time excessive?

Pig

Mine is 3 min fill and 1 hr drain and was very succesful till i had the crash totaly unrelated thing [got some over spray in fish tank]

I don't thikn the the F&D cycle times are super critical.

F&F had had VERY good growth with 3/60 minutes

My times are 2/1 minutes!

mine are 18 mins fill and one and a bit hours empty

Just wondering how many GB's you have at this size, and what pump you are using?

Regards, Sam

Thats pretty close to what I have miss piggy, I think I get about 8-10minutes fill, an hour to drain.

Hi Sam,

There are two grow beds and the pump details are:

Davey
Dynapond pond pump 8000
S/No: 06116-0604100628
10m head
Qmax 140Lpm
280Watts
240V
made in italy

It cost about $300. The fish tank is 1750 by 900 deep. Haven't filled the tank up yet - only just above the pump to flush the gravel. Oh and by the way the gravel was seived with a sapphire seive in a container of water before putting it in the grow bed. This removed most of the clay and sand. Otherwise it would form a cement like layer on the bottoms of the grow beds. Took hours though and its hard on the back.

Have priced perch from a farm at wagga wagga as they were recommended to be of good quality but with courier fees it comes to about $2 per fish. I'll be sure to get the system right before I order them. Would hate to have a mass kill.

Pig

sounds like you have all the parameters sorted. I had my eye on that davey pump initially (to expensive for me though, but worth the investment ) Sound like a good sized system, are the gb/fish tank new?

look forward to seeing some pics if it is no trouble