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View Full Version : Water flowrate in Raft and NFT setup!!



Davi
12-09-2010, 01:01 PM
Hey guys, hw's the season treating ya?

I'm considering using a merge between NFT and Raft for my AP set-up where i'd be using NFT Channels but the channels would be filled similarly in the way that the raft is filled with water.
This is simply just to not have to make the big Raft bed :)
What i wanted to know was how fast does the water flow through the plant beds and the NFT channels? is there a recommended flowrate for optimum plant growth and performance?

Thank you,
Davi

JCO
12-09-2010, 03:41 PM
Welcome to the show....pull up an easy chair, relax and stay awhile. New voices are always a welcome addition to our family..! Whatever questions you have on you mind, this is the place to get the answers so pick a topic of your interest and start your own thread and Enjoy.

NFT in PVC or rain down spouts, though touted a lot on the net, is not an optimum way of growing a large number of plants. The film of water transversing the length of the tubes can go from a 70 temp in the beginning to well over 100 degrees by the time it gets to the other end and that will literally roast the roots of the plants.

Unless you can keep the temp down by lessening the length of the tubes which would defeat your purpose, they will not be worth the effort or expense. Take it from one who found out the hard way. The rafting method is best unless you are going with a media set up.:mrgreen:

davidstcldfl
12-09-2010, 03:52 PM
Hi Davi, My troughs are like Friendly's AP in Hawaii...aprox a foot deep, 4 feet wide. I'm not sure of my flow rate ?
I remember reading, Friendly's said ...they tried 2 gals per hour ,up to 20 gals per hour and didn't notice any difference in growth.
They stopped the flow in a couple beds for a week or so, before they noticed a difference in growth.

badflash
12-09-2010, 03:59 PM
Flow is more for the fish than the plants. You need to pass the water through to have them absorb the nitrates and phosphates. It needs to come out as fast as the fish put it in.

I posted some calcs someplace on the forum a while back. If I can find it I'll post the link.

jackalope
12-09-2010, 07:17 PM
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urbanfarmer
12-10-2010, 02:23 AM
Hello and welcome!

That would be a raft system then.