Backyard Aquaponics
A place to discuss aquaponics

I can probably do up a little diagram here in a few minutes. I don't think I'm likely to manage any useful pictures since The sumps I have set up this way are not easy to see into, let alone take a picture into.

I'll go work on a diagram since that will explain better than my writing ever could.

Ok I said I'd do a diagram, not sure how much it will help but here goes.

Here is a link to the type of float valves I've found most useful and reliable for this so far. I've simply used the plumbing to hold the valve in place as the metal clamps are meant to hold it to the top edge of a stock watering tank and not really useful for lower down in a tank so I just don't attach the metal bits when I put it together.
http://www.tractorsupply.com/webapp/wcs/stores/servlet/ProductDisplay_10551_10001_28397_-1______?rFlag=true&cFlag=1

Thanks for the quick reply TCL, I think I get the idea. Is the water from the top up source just gravity fed into the valve?

Once the water gets below the valve it opens and lets water flow in untill it is topped back up!? It seems it would only be letting a very small amount of water flow into the tank when it is required. Or is there a point where from one flood and drain cycle (say in a 1000 ltrs of grow bed volume) to the next the plants could soak up a resonable amount of water requiring a lot of top up? I wouldn't think the top up tank would have to be all that big. Maybe a 20-30 ltr bucket? What sort of top up rates do people experience in systems this size?

thx taz.