Ebb & flow - enough gallons to last 5-6 days.

I can calculate gallons needed to fill a table/gutter, but how many gallons in excess of what you need should your reservoir be if you change it out every 5-6 days, considering absorption & evaporation?

Bloom room is indoor, veg is greenhouse + supplemental lighting. Ebb & flow will be in both.

My 4x4 table has a 60G rez and I only add back maybe 10G, every 6 to 8 days for large plants and could easily go 2 weeks when they are small. I adjust the ph and nutes evry 3 days but you could let it slide 7 days easy. I only change the rez every 3 weeks or so. Yields are excellent .

fred flintstoned said:

My 4x4 table has a 60G rez and I only add back maybe 10G, every 6 to 8 days for large plants and could easily go 2 weeks when they are small. I adjust the ph and nutes evry 3 days but you could let it slide 7 days easy. I only change the rez every 3 weeks or so. Yields are excellent .

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Ok, cool. Thanks. I pH every day, hand-feeding. Ebb & flow will be so much less labor, pH'ing daily will be a breeze.

Also, cleaning a short 3/4" hose will be easier than drip lines and I can continue to use both salt + organic material in solution.

And using an oversized reservoir is a good idea (topping it off along the way), as cleaning is less of a concern than with drip. I was trying out too many strains at once, with different flowering times; so, it's only because I've got a shortlist now that I can do this. One strain per gutter, one pump per gutter. Same rez while they're in same nute phase. Smaller individual rez while at different nute phases/ripening.