I am moving along at a slow pace but my goal is to have the aeration system up and going by mid summer or earlier. I've been digging the ditch to bury the air line. I have two thirds of the ditching completed. And I've been thinking maybe it's time to ask a few more questions. The distance from the air pump to the pond manifold air station is approx. 1800', and then another 300' for each line for two of the furthest diffusers. This will make the longest distance to pump air will be around 2,200 feet. There will be 4 to 6 air diffusers in the 3.5 acre pond. One co has recommended 6 and another has recommended 4 diffusers. And if I can, I will add another station to a grow out pond. These are well known brand names. I wanted to ask and make sure I do not order the wrong size tubing for the air pump to the manifold. Question is what size tubing would you run for the 1800' line? And if you think of any thing else to add, please do.

Thanks
Tracy

Wow! That's a long run. How many CFM are you going to be pumping?

Tracy:

Save yourself some $$ and go to a plumbing supply place. Buy the poly tubing that uses barbed connectors to put underground. This is NOT the self-sinking airline that you would use in a pond, it's like the drip irrigation tubing you see in the big box stores but larger sized. When connecting the tubing and burying it, I would use both abs cement and stainless hose clamps on the barbed fittings. IIRC the longest run of 1 1/2" tubing I could get was 500', less connections under ground to worry about.

I have a client where their layout is similar to yours - a LONG ways from the electric to the pond. They also wanted to do a semi DIY system. From the compressors, it was quickly upsized to 1 1/2" tubing, and that is the size that was terminated into the remote valve boxes near the shore of the pond. From the remote valve box, the self sink air line was 1/2" to .6" I.D. I have run 700' of that airline to a 5 diffuser air station weight box or diffuser assembly in the pond.

Thanks esshup, So, 1.5" poly tubing with barbed connections? Not sure I understand the point or comparison you make with the drip line, I am a little slow sometimes when it comes to DIY things. Is this a comparison as to the lengths one can purchase? Both Companies quoted prices from the shoreline and not from the farmhouse storage room.

Bill D, I am not sure of the size compressor, its been awhile since I visited or read their bids and would have to go back and look for the size compressor. If memory serves me, which it doesn't all the time, it was more about the volume instead of the pressure when it came to the compressor. But what do I know? I do remember, It's not cheep

Tracy

Tracy,

Esshup is talking about line that you would normally used in a drip irrigation system in a garden or lawn setting for running in between the compressor and manifold system. I would go to your local plumbing warehouse to find this tubing as per Esshups suggestion-also they should have the barbs to go along for this line.

Lengths of line from most manufactures on the air systems ship in 100' or 500' increments.

Joshua

josh, thanks, that is what I thought, but needed to clear things up a little

Tracy

Josh is correct. I referred to the drip line because some people don't know what poly tubing is. It's also the same type of tubing that is used (at least around here) to go from a submerged well to the bladder tank.

It's good stuff but you need to be careful not to kink it. It kinks easy and does not unkink well! You pretty much have to cut the kinked area out and splice it with a barbed fitting. I used it as the discharge line from my geo unit in the basement to the pond.

Bill D. Correct!! I had to make a few buried runs of 200' and 400' last Fall when the weather was getting cool. I unrolled the tubing the day before and let it sit on the ground, soaking up some sunlight to warm up before I put it in the trench. I also used a heat gun very carefully where I had to make some tighter bends than I was comfortable making with it at ambient temp.

One thing that I learned was to use the least number of couplings/splices underground as possible. AND if I did, make sure the barbed fitting was clued and hose clamped in place. If not, the shrinkage/expansion of the tubing over the year might pull it apart underground. That's why I prefer to install it when it's as cold out as possible - no where to go except longer.

If I did the math correctly, a 2000 foot run of PE Polyethelene pipe changes length by nearly 100 inches with a 50 degree temp change! The stuff has a huge coefficient of thermal expansion (83 x 10-6 in/in F)!

Yes it does. Now you see why I like to do it with no connections underground if it all possible and if I have to connect it, glue and stainless clamps. I would not hesitate to use 2 clamps per side of the barbed fitting either along with the glue.

For a lesson in futility, try rolling up 1" dia tube, 400' long that was laid out for a day. Oh yeah, make sure the ambient temp is in the lower 40's..........

esshup, since there is some concern of leaks or separation @ the joints, maybe I could arrange to have the connections above ground. My plans are to lay the line and push the dirt back using the tractor front end loader. And now you have me thinking about shrinkage or contraction during colder weather. I may have to give this a little more thought. And, I will not be seeing any cooler temps until the later part of November, most likely. Ha, if I wait till July, our temps would make poly pretty flex able, and if not careful it might just get pretty hot when handling it with out gloves.
I have 7/10 of a mile of 2" poly laid out now and use it to bring water from the well to the pond. I have never noticed any shrinkage of this pipe, its pretty thick wall pipe. Thanks again for the help

Tracy

Tracy,

FWIW I would bury the connections. IMO you want the pipe to experience as little temperature change as possible. Exposing the connections to the air temps will create areas with large fluctuations in the temperature. The ground provides insulation and will minimize the temp fluctuations. If you are concerned, maybe you could flag where the connections are so you can dig down to them if there is a problem.

Just my 1 cent

Bill, I was not concerned about the pipe moving till after this discussion, now you have me thinking again lol
Those engineering numbers might give some reason to over engineer
Tracy

I think you'll be fine as long as you follow Esshup's recommendations on splicing. The 100 inch number I gave is in Free State. A buried pipe is considered more Constrained State as the friction of the backfill on the pipe restricts movement. With movement restricted, the pipe will experience tensile and compressive stresses with temp change. It will still move some but not near 100 inches and I doubt you'll see 50 degree temp fluctuation underground. FWIW I would drop the pipe in the trench, leave it over night to come to ground temp and backfill the next morning.

You could always put the connections in an underground sprinkler box. That will keep the connection underground away from the sun, mowers and rodents chewing on it, but still allow easy access in case of maintenance.

I never knew poly had that kind of movement, now I'm a little concerned since I just poured my slab under my new pole barn last week, and I put poly in the slab to get air lines out of the building. I made up four 1/2" elbows to put in the concrete and will splice on to it later after I finish enclosing the shed. I did not cement the elbows, only used the stainless hose clamps. The elbows are beneath the slab and I suppose I could dig them up and re-do them....should I do that or wait to see if I have a problem with them?

IMO I would leave them be. I wouldn't worry about short runs, especially under concrete in a building where the temperature fluctuations will be small. TGW1's run is well over 1/4 of a mile!