DKKA- so, you like the way luft performs? (adjustability, output, maintenance) What type of application are you using it in? (in a skimmer? At what depth? What sort of diffuser? Just one diffuser or multiple?) My thoughts on getting just one was for the sake of comparison, plus the fact that they were recommended by Calfo. The disributor can get them for me at about the same price I found online for the least expensive one, the difference being I don't pay shipping from the distributor.
camarojweed- Thanks for the empathy. There isn't a doubt wether a compressor could supply the psi. One of the questions I wondered about is the volume required to supply air to 44 skimmers, about 150 outlets for the air lifts, and another 30 - 40 for the water prep barrels. According to the guys at Aquatic Eco, I need 2.2 cfm total @ 4 psi to run 44 skimmers if the limewood diffusers are new/ unclogged. As the diffusers become clogged over time, the pressure need goes up a little. For that part, the linear piston pumps seem to me to be better suited to the application. One of the few pieces of knowledge I do have is that LPP's are self regulating (typically) and repsond to slightly higher resistance/ demand by increasing the stroke length of the floating piston. (so Chris, That e-bay LPP sounds plausible). Also according to Aquatic Eco, to run 190 outlets for all of the bubbler lines (no diffusers), I need a total of 66.5 cfm at a consistent pressure (they say probably around 1.5 psi). I do have an old compressor in my garage that I got from my late brother-in-law (by marriage) but I just haven't done any research on them and don't know enough about them to try one for this application(s).
H2OENG- I recognize the names of McMasters as well as AREA, so I'm sure I looked at their stuff during the research phase. Keeton kinda sorta rings a bell, but I don't have them on my favorites list so I either didn't look, didn't like what I saw, or have long since deleted them. By this time, some of this research was done almost three years ago. (GOSH, has it really been a year since I started building? I'm way behind schedule.) I would, at this point, agree with not using a compressor. I don't know enough about them, (of course, I don't seem to know enough about blowers and LPP's either), and even the possibilty of oil (or oil vapors) getting to the tanks is enough to deter me. Plus, I just don't think it would look "right" to have a compressor sitting there in the greenhouse. I have really been enjoying the quietness of not having a blower running and I know compressors make allot of noise. Maybe the best option here is to have the first blower repaired (it had an output of 70+ cfm), return the smaller blower (was going to do that anyway), and get one of those LPP's off of e-bay for the skimmers at about 1/4 of the cost of buying one of a similar size/output from a supplier.
melev- I didn't know Calfo thinks you're crazy. Darn it, now I have to ban you from my thread. :lol: I hope you catch the lol behind that, I really do enjoy having you around. You have allot of good ideas and have contributed much for all of us, and not just here, but for all of RC. Granted, Calfo has tons of experience and knowledge, but I don't talk to JUST him and I don't take everything he says as gospel. I find several sources who all seem to have the same opinion. There is just too much that can be (mis)inferred with text comunications, and things that might work in one application that don't in another. (Plus I seem to have this need to go ahead and find out the hard way for myself anyway, no matter what anyone else tells me
).
I'm positive there aren't any leaks or obstructions in the blower manifold. Leaks I should be able to hear and I dont think a leak made by a void in a glue joint (not likely anyway, I've passed literally hundreds of pressure tests on my plumbing work) or leaking thread would make enough difference to really affect the output reaching the air lines. I have had the manifold running with open ends on a few occasions, (like when I was first setting it up or making alterations and after drilling and tapping for all of the outlets to blow the pieces of plastic shavings out of the manifold), so there arent any hindering obstructions. The over heating was probably due to the small number of outlets I was running combined with pushing the pressure too high in an attempt to push the skimmers. This second blower, I believe, is just undersized (20 cfm @ 1 psi). Seems like most of the people I'm talking to at the companies are not familiar with applications (salesman) and don't have engineering back up. The few engineering companies I've taked to either don't want to touch the design (to "small of a project for them) or have given me the outlandish recommendations. With Aquatic Eco, at least the guy who emailed me back has an engineer to talk to, is an aquatic biologist and they have lots of experience in setting these systems up.
cseeton- go to bed and get some sleep man :lol: I would know even less about using LN than I do about compressors, but just to play the devil's hand and the interested fool... How much is it going to cost, in electricity or propane, to heat the LN? (and isn't N a gas at atmospheric temps? so maybe I should be asking how much is it going to cost to keep the LN @ -200 C.) What kind of piping equipment am I going to need for the LN? Expansion tanks? Reserve systems? How fast does the pressure fall off as the nitrogen is depleted? Special storage considerations? Hazardous material? Fire/explosion hazards? How will N affect the ability of the bubbles in the skimmer to attract proteins? (I do know that our atmosphere is like 78 % N and I believe it is mostly diatomic (N2) but straight LN might have some affect on surfactant abilities). 'nuff said.
