Backyard Aquaponics
A place to discuss aquaponics

I'm not as good at the math to tell how much water can flow by gravity through a given size pipe but I do know it is a good idea to pump the volume of your fish tank each hour. As in, if it is a 4000 liter fish tank, you want a pump that can move at least 4000 liters at the needed head in what ever amount of time you intend for the pump to be on each hour. Tricky part here is you then need to hope your gravity plumbing can handle that amount of water in that amount of time.

As to stand pipes. I like to make my stand pipes removable so that I can pop them out and add more holes in the bottom of them if I need. This might be tricky depending on the way you sort out the plumbing. Mine are threaded into bulkhead fittings but going into masonry is a different situation that I really don't know much about myself. Anyway, I like to start with one or two small holes and see how long it takes to fill the bed once the media is in then if the bed is filling too quickly, I can pop the stand pipe out and drill more or bigger holes until the right flood speed is reached. The more/bigger holes mean the bed will drain quicker but you don't want to make it drain so quick that it never floods all the way. At full flood you want water just trickling over the top of the stand pipe and the top of the gravel should stay dry. We usually say the water should remain 2-3 cm below the surface of the gravel.

Good luck with the plumbing through the masonry. Perhaps Creative1 has some hints since I think he has done concrete fish tanks for people before.

Thanks TCL. Another growbed is coming into existance. I am thinking to concrete a 90 degree bend into the floors of the growbeds with a short piece of pipe coming up into the bed with a sreight connector glued on and then the stand pipe can simply press into the streight connector and then it can be popped out easily. Here is a slightly elevated pic of the system so far.

For flow rates the attached is a good guide.
http://flexpvc.com/WaterFlowBasedOnPipeSize.shtml

I saw a program on telly once about weird or gross jobs, there was a guy in the US who travels around collecting these "mouse balls" and selling them to schools for science. The kids disect them. Was one on thise things where you just go "Wow who would have thought to make a buisiness out of that!"

Great tanks by the way. I also have a wish to incorporate some concrete quadrilateral based tanks into the landscaping at the front of my place that will all be plumbed into my AP system.

Check out these two videos for integration into the building!!

http://www.youtube.com/watch?v=0C9Ugc4ZO4w
http://www.youtube.com/watch?v=Zkdt40dg ... re=channel

:-)
KM

Getting the last two growbeds plastered today.

Those look so cool!

Star-gates??? Get them upright ,, dial away:)

Thanks TCL and Chappo. They are quite stargatie crop circly things. TCL, I am thinking of going for no two in the SLO ideas: taking the drain pipe up the inside of the tank and then out the wall near the top, and was wondering when you say not too close to the top of the tank how close is not too close. I guess if your outlet is too small to drain the input from the pump then you have problems but I am going to have two 50mm drains which have ample draining capacity as laid out in the link provided by Chappo: 6600 Gph. I was thinking to put it through at the second course down from the top ehich will put it about 120mm down from the top. Any Ideas?

I can't seem to solve the standpipe debacle. Option 1 is to put the pipe through the floor and then go under the footing and then to the sump, which would be the easiest except that the pipe would run in a big U to go under the footing. Should have cast a pipe through the footing Option 2 go through the wall at the slab height and then up into the stand pipe which would have all sorts of complications and option 3 would be to go through the wall above the floor which would seriously raise the height of the drain hole which would mean the GB would not drain very far down. Option 1 is my choice so far but would appreciate any comments. I am also thinking that I should make one of the beds into a duckweed pond with Floating rafts for lettuce. I have found a plastic Tank of 3000 litres at a chaps place that lives in some old stables nearby. His horse kicked it in but I can get it welded up ( I don't think he knows this and is quite a drunken bum so would probably jump at the oportunity to make some cash on it ) I could use this as the sump and then I would not need to do such major excavations and then build within those excavations which has been worrying me a bit cause the sand is pretty soft here and the excavations tend to cave in a bit. I would need to reinforce the tank a bit to stop it from caving in I would imagine. Perhaps a couple of concrete rings as I fill it in would do the trick. It is a round rotomoulded water tank.

Looking good Brian, I'm with you on the option 1 idea mate.

Might be a bit of extra digging but if the soil is soft like you say? I wouldn't think it'd be any more work than options 2 & 3.

As long as the lowest point in your grow bed is higher than the highest point in your pipe work back to the sump to allow all the water will drain out of the grow bed it should work well. There might be some water left over in the pipes (in the U bend under the footing) after draining but it will get pushed out on the next flood and drain.

So long as you have ample drains to keep the pump from filling the tank above the outlets, then it is fine to have the outlet go through the side wall of the fish tank. But remember that you then have no easy way to lower the water level below that point and if something cloggs your drain lines, you don't have as much margin before you overflow. I've had fish jump out of a tank when the water level is too near the rim and the lid on the tank was not sufficient to bounce the fish back down.

As to the grow beds, option 1 or option 3 I think. Depending on whatever is easier to seal up properly.
To make option 3 drain down better, simply put the holes in the elbow instead of in the pipe leading down to the elbow. It is just a little trickier to access the elbow for changing the holes in it but still probably possible if the gravel guard is big enough.

I am going with option 1. I have made up the standpipes and installed them in the GB's. I was chatting to my neighbor two farms down and he told me that he had two tunnels in an unassembled form on his farm and that if I assembled one on his place I could have the other one for free! It's a 8m x 12m steel frame tunnel. no plastic on it but still what a great deal.... I wonder how hard it is to assemble them Like a big chinese puzzle.

Well if you can tell what type of tunnel construction it is, perhaps you can find instructions online to help you out. Great deal, so long as all the needed parts are there.

Standpipes with adjustable flow. by twisting the pipe in the socket you can set the drain speed