My guess is the pump manufacturer rates the pump based on keeping goldfish alive.

It's been my experience that just about any amount of constant bubbling in the nutrient reservoir is enough for plants. Personally, I've used the $5 ones to run as many as 4 bubbler stones at one time and it has worked out great.

freemangreens,

No offense to corrumpu who suggested that I need a huge pump to provide enough air to 14 four-gallon buckets but I have read a lot of your posts and they show you don't whistle Dixie.

I do plan on mounting the pump above the buckets, though I have to design a "wiring" diagram. My GH will be 12x16' using four rows of buckets (no more than 40, each holding a max of 4.25 gallons) Two rows in the middle, one on each side.

So much to design, so little experience doing it!

Mike

The water temperature dictates how much DO water can hold.
If the water is cold you won`t need much aeration to reach 6-7ppm. If its too warm no matter how many gallons of air you pump in you won`t make it to 3ppm. Buckets in a greenhouse sounds like it`ll be pretty warm water.. so go big :)

I don't whistle dixie? wtf is that? I'm sure this is an insult but it's lost in translation. If you imply that i'm not optimistic... I am but you have to pick your corners to cut.. if you are already looking at a durapump (which you mentioned in a different post) then you are already in a good price range for the AP series pumps which I would say are vastly superior to the sunleaves. Just trying to help.
AP-40, 60 etc etc.

In DWC.. more air is better. Period.
buy a sunleaves dura 1440 GPH for 75$ or buy a 130$ that is quieter and pushes WAY more air. There is no way you could properly aerate 150 sites with 1440.. just no way. Where are you getting that number? Don't believe the stats on pumps they are BS.

Take a look at this company.. http://www.currentculturehydroponics.com

They have some very nice DWC setups which use the AP-series pumps. Overkill on the pump I agree but the most expensive tool you buy.. is the one you buy twice. I OWN a durapump.. it did NOT give me the bubbles I was looking for. I have (8) 5 gallon buckets with one controller. Only 40 gallons total with sintered air stones. They are bubbly, but I wanted froth. I got an AP-100 and it looks like a hot tub. Now I use the durapump for worm tea.

--chris

wrong. more air is not better, period. There isa point of diminishing returns where more air will eventually create carbonic acid.

its not the bubbles in the water adding DO. its when they burst on the surface. a waterfall is a better oxygenator than an airstone. A powerhead is all you really need, but thats not practical for n+1 buckets.

Here is a link that might be useful: alita linear air pumps

corrumpu,

No offense intended at all. Basically, not Whistling Dixie means the guy knows what he is talking about, and I've read enough of freemangreens' posts to know he gives good advice backed by experience.

Mike

I contacted Dr. Worm from Worm's Way, a respected hydro store here. The recommendation for large tomato plants is four gallons of air per hour per gallon of water.

Mike

I use evaporator cooler pumps. I use two pumps to push water to a height of 12 feet. The fluid is transfered to a resivoir and then flows through a pipe that is perf'd. The falling water into the res o's the water and provides the plants. 400 gallons res. No joke. 30 to 80 plants depending on whats goin on in the green house. You can scale down of course and I almost promise that the evap cooler pump with a (100 percent) duty cycle will last longer than an air pump, especially since contaminants are no matter. About 40 bucks, but you have to have the room. I have a large g-house, but Ive done this setup in a small atrium and it works great.