Don't post often as you can see. I obviously missed those threads, Hence my post.
Thank You for your informative reply.

ATB

Some of those pumps (iwaki) supposedly last longer if you just leave them on 24/7, and that's what people do, that's what I've read anyway. I have an iwaki md70rlz, but I'm not using it yet. I'm just doing some hempy buckets right now. (Lame, I know) But I do want to know more about this, since I will be using that pump sometime soon..

Nothin wrong with hempys. Just look at what Earl's doing with those Purple Cindys. I have a preset cycle timer 1 min on-5 min. off. Before they ran 24/7. I couldn't see any difference in yield or anything else. I just figured less wear and tear and elec. They aren't Iwakis so I hope this doesn't shorten their life.

These Iwakis are nice pumps Harvey, that's what I run on the chillers.

Damn look at the post number. Damien post.

I don't really know how the iwaki pumps are constructed, I suppose I could do a little research myself, instead of just being lazy and asking on here, haha. But I don't really know how turning the pump on and off could wear it out more quickly, unless it is somehow analogous to an engine. (with hydrodynamic bearings, you have metal to metal contact, until the rotational velocity is high enough to build enough film strength of the oil to separate the parts, since the film strength of oil is directly proportional to rotational velocity. That's why starting an engine causes so much wear, and why using a flat tappet cam setup with stiff valvesprings will wear the cam/follower surface out more quickly at idle than when the motor is spinning. And why the 10psi per 1000rpm rule is bs.)

But back to the aero shit, I think it's going to come down to whatever makes the pump last, and if cycling it doesn't affect that, then down to power consumption. I don't know. I'd guess if the pump produces enough pressure to make really nice, small droplets, then you're not going to see any benefit as far as increased o2 to the roots by letting that little layer of condensed h2o on them evaporate, by turning the pump off, since the droplets will already allow enough o2 to the roots. I mean, isn't that the reason why true aero grows so fast?
I'm trying to remember who said that about not cycling the iwakis, but I'm drawing a complete blank right now. I'm sure we'll figure it out though..

Aero is truely a test and run (to deside upon final settings best suted to what your looking for...) But hay who doesn;'t like a good aero discussion>?!?!

Actually, the ideal on time is one second with a pause of 5 or so minutes. To achieve this you need to invest in a sophisticated digital timer that is accurate and repeatable.

I have current TAG journal using AMS and LED with 5000+ visitors on IC that you might be interested in.

One second?
So you're not even letting any solution drain back into the reservior. It all just evaporates/is absorbed before the next on cycle.

My intuition tells me that by doing that, the roots could end up with a different nutrient concentration left on them than what is in the reservior.

?

One second on is no where near enough time. You should be around one minute on and five to six minutes off. This allows for Oxygen to get to the roots in between feedings. If you leave it on 24/7 you'll probably drown your plants.

That 1 min on/5off recommendation has been floating around youtube and the net, and we know it works, but I've observed some people saying up to 45 minutes off. My first reaction to that was, "what?? You'll totally dry out the roots!" But after watching my system actually work, I don't know. After turning my loud ass little iwaki pump on, there's no way I'm running that 24/7. Not to mention the benefit of reduced exposure of the solution to that powerful, iron sucking magnet at lower on cycles. It's a 100% humid environment in the tubes, they drain right into the reservior(s), so maybe a longer off time than you would innitially think would work. I'm going to experiment, checking on the roots and the plants, and try to see. Right now I have my setup approx 3.5 min on, 25 off, just a guess. I might go shorten that off cycle a little right now. First day of getting it running.

Has anyone experimented with extending the off time to the point where they observed a negative difference? (or is that one of those "trade secrets", lol. It's all good either way)

I left my pump unplugged for 2 days.
OOOps
They are still alive.
Pretty stressed, but budding OK.