# NFT reservoir size????

Discussion in 'Grow Room Design/Setup' started by TheActivity, Jan 3, 2013.

1. Need help calculating how big of a rez I need for an nft system. I will be running 8 20ft channels. 12 plants each channel, 96 total. I know they say the bigger the rez the better but I am trying to be economical and not have a 300 gal rez to change out every week. Also wondering how big of a pump I would need. Any ideas????

2. Just get the biggest pump you can find. That's what i do when i go to a shop, and need a pump, That way i know it works. but what your doing is much more large scale then mine, and you probably buy pumps that make my pumps look like sprinklers.

As long as there's enough water to give non stop continuous flow to the system and the roots, it doesn't really matter what size you get. Load it up with water and give it enough water to fill up the system completely, then increase it by as much as you want (at least 3x as much as whats in the system i reccomend)

I'm sure there's a complicated calculation to all of this, but this is the easy way of doing things.

Dont NFT's run mostly on gravity?

3. That res is going to be HUGE! How big are your channels and how deep do you want to flood them?

I'm thinking of building a similar system for my next grow, but only about 1/4 of the size and < half the plants.

4. I was hoping someone wouldnt say that! lol I think I am going with 9 inch wide channels, 8 of them, each 20 feet long. I only want about a quarter to a half inch of nutrient solution flowing. What do you consider huge? 50, 100, 400 gallons? Im hoping to be able to keep it under 100 if at all possible. 50 would be ideal. The less the better.

Fluorescence, they do flow through the channel by gravity but I still need to get the solution from the rez up to the beginning of the channel. Gravity does the rest at that point.

5. Ok, well if you're only flooding about 1/2 inch of water it's not that bad. I'm curious why use this method over ebb & flow? Obviously there is a pretty big water savings, but with that little trickle of water I don't think you'll get nearly the same results as flooding with 4-6" of water and growing a huge root ball. I only ask because I'm going through the same design considerations myself - I like the simplicity of NFT, but I like the results of ebb & flow. If yield is more important than water conservation, i don't know if NFT can even come close.

At any rate, here's how I would calculate that:

1/2 * 9 * (20*12) = 1080 (cubic inches of water per channel)
1080 * 8 = 8640 (cubic inches of water to flood eight channels)
8640 / 12 / 12 / 12 = 5 (cubic feet of water) = about 38 gal.

You'll have to round up for water in the lines, evaporation, etc. But you're definitely fine with a 45-50 gal res.