How do I pick the right size air pump for DWC?

Is there a formula for selecting the right size air pump for DWC? Is it based on a certain number of liters per minute (LPM) per gallon of water or a fraction of the rated performance intended for an aquarium, or something else?

get a big one more bubbles more better
you get the point

Yeah I find a small ($10-20) one will do one <50L container no probs(with a big airstone). Double oulet will do 2...etc

It depends on what you want the bubbles to do. If you just want them to oxygenate the water, a walmart aquarium pump will do. But if you want it to be bubbleponic and eliminate the need for feeder tubes, you need high level bubble activity which means a robust pump. I use this one:
http://www.discount-hydro.com/productdisp.php?pid=412&navid=8

Hey IS, I'm running some 3 1/2 gal buckets. They have a little over 2 1/2 gal of water when set up. I have 2 5" airstones in each one. Would that pump run 2-3 buckets? 4-6 5" stones total. Thanks for the help.

Resin225 said:

Hey IS, I'm running some 3 1/2 gal buckets. They have a little over 2 1/2 gal of water when set up. I have 2 5" airstones in each one. Would that pump run 2-3 buckets? 4-6 5" stones total. Thanks for the help.

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I run 4 12 inch stones easily with that pump, you should be fine.

Okay, thanks guys. I know more bubbles is better for creating that semi-aeroponic environment above the water. Illegal Smile, you even repped me recently, "I wish more newbies would get this simple fact."

I've swapped out three pumps so far for my first 5 gallon DWC, each one larger then the previous, and I've seen faster root growth each time I replaced a smaller one with a larger. Now I'm ready to fully commit to all DWC grows. This means I need more/bigger buckets. But before I pick a pump I was curious to know if there was a point where more bubbles gave diminishing returns. I've seen what minimal bubble action does, was looking to find a magic number for as little as 10 gallons of water and up to 60 gallons of water. So far I like how 1LPM of air per gallon of res performs, but wasn't sure if I should go higher.

IS, thanks for the link. How many gallons of res do you use that one pump for? Here's another pump (60LPM) I was considering. Would probably use this for 60 gallons of res, but maybe I'd use yours (~38.5LMP) if I only have about 30-40 gallons of res. I plan to use 12" air strips and/or bubble walls because I've noticed these work best for me. Does that sound good?

Thanks IS I just ordered one.

the fromula I found in the lucas thread. That is a good read for all hydro growers.

It is simple, lol, ahem, 1 watt per gallon. So for a five gallon bucket I am using a five watt airpump. I would be fine with a three watt but five is optimum.

Another point on pumops - get a spare. If one goes out you have a major problem.

tea tree said:

the fromula I found in the lucas thread. That is a good read for all hydro growers.

It is simple, lol, ahem, 1 watt per gallon. So for a five gallon bucket I am using a five watt airpump. I would be fine with a three watt but five is optimum.

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I've read a bit on lucas too, actually trying it in my 5-gallon DWC. I must have missed the formula you just shared. If I understand this right, looking at a new 5w pump in front of me, I estimate about 2LPM for every gallon.

The pump I've used so far is only 3LPM and honestly I'm quite pleased with the results. I was hoping to use my new 5w 9LPM on two 5-gallon buckets, but from what you're saying I should have one pump on each bucket for ideal conditions. I'm sure it'll be fine using the one for now, I'll pick up another in a couple weeks.

Illegal Smile said:

Another point on pumops - get a spare. If one goes out you have a major problem.

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No doubt, I've always been a bit of a boyscout that way. I have a few spare pumps right now. I wanna go perpetual so I'm sure they'll come in handy for cloners and such too.

Illegal Smile said:

Another point on pumops - get a spare. If one goes out you have a major problem.

Click to expand...

Yes!! its always good to have spares! imagine you check your babies before you head off to bed only to discover your pump has died! oh noes! and the stores wont open for another 8 hours eek...im very big on back up plans

In regard to backup plans, if I absolutely must I can easily switch to hempy buckets mid grow. Done it before.