Hi Folks, I introduced myself in the introduction forum a few weeks ago and since then I've been looking through a ton of posts on the board here, trying to learn as much as I can so that I could at least ask the right questions. So...Here goes!
I've attached a little drawing to illustrate my ponds shape etc. but basically it's a kind of taller guitar pick shape - about 70 feet wide at the shallow end, 30 feet wide at the deeper end and about 110 feet along each side. Max depth right now is about 9' until it gets really hot and dry, when it can drop to maybe 7'. The sides on the deep end are fairly steep, and I'd guess that an average depth overall accounting for the super shallow and deep would be about 5 feet. The pond is at the end of a wooded valley, and is overhung by pine and sycamore. The runoff it receives comes through a stand of white pine and the pond is very tea colored. I've never done a ph or any other water tests. Aquatic life is good. Frogs, bass, bluegill, an itinerant snapping turtle. Weeds/vegetation: Cattails in the shallow end which don't bother me, some pond weed - but lately terrible Filamentous algae mats.
The pond is about 300 feet from my garage, and with no power at the pond I intend on placing my compressor in the garage and running black pvc through the woods on top of the ground down to the pond. There is a very gradual drop, about 10-12 feet in the 300 foot run. I'd like to start with a used compressor that I can rebuild if it becomes necessary. I've had good luck on ebay with many things, and thought I'd try there unless I hear from folks to go a different way. I see a good number of under $300 Gast Rotary Vane compressors on ebay, several with various 0523 model #'s - I understand that one can buy the vanes and gaskets for under $100 if it needs a rebuild. I've not done that before but I'm pretty handy and can figure things out with the help of good folks on the internet! My intent is to aerate so that I can introduce bacteria to reduce nutrient levels in the pond and, hopefully, slowly chip away at the bottom sludge. Hoping that this will help to solve my FA problem as well. I also intend to reduce the number of trees around and especially reduce the number of limbs hanging over the pond to cut down on the leaves.
My Questions (finally): 1. What size and type (rotary vane or rocking piston)of compressor would you recommend for my situation? 3. How many air stations would I need to help my pond? 4. Stones or Diaphragm?
I'm sure I'll have follow up questions to your answers but in the meantime that's what I can think of! Thanks in advance for the help!
The pond dimensions calculate it to be less than 0.2 ac and close to 0.15ac. A 1/3 hp rotary or rocking piston would be very adequate. I would start with two diffusers one each end. Larger end could use a dual head diffuser but not necessary since the pond is only 70ft wide, and deep end a single membrane. I prefer the rubber membrane diffusers simply because they are easier to clean which should be done every 1-2 yrs for best performance. If you plan to run the aeration in winter then I highly suggest a pressure relief valve in case a water plug freezes somewhere in the over the ground airline. Rebuilds are somewhat easier for rotary vane vs rocking piston.
Do not expect the aeration to consistently reduce algae problems. aeration in itself has IMO not been proven to reduce dissolved nutrients which are causing your plant problems. Aeration will improve the overall water quality throughout the year, but you will notice variations of transparency which is normal even with aeration.
aka Pond Doctor & Dr. Perca Read Pond Boss Magazine - America's Journal of Pond Management
Bill, anything I should look for in particular if I'm looking at used 1/3 hp compressors? Oiless is about all I know to look for.
dg84s - the line will run through my woods, no danger of mower or other damage that I can think of, but do critters chew on that plastic? Is that the reason you'd bury?
As Bill says a 1/3rd hp would be very adequate and if it was me I'd go even smaller with only one diffuser in the center deepest spot. I say that because I have a 1/3rd hp rotary vane feeding three 1/10 acre ponds to 9 feet and it's more than adequate.
Last edited by Cecil Baird1; 06/03/1411:35 AM.
If pigs could fly bacon would be harder to come by and there would be a lot of damaged trees.
The extra money could be used to make the one diffuser larger or multiple heads (dual or triple) thus increasing the strength of the boil or water mixing which would push water further around in the pond toward the shallow end. Most often with decent wind action water will mix naturally 3 to 5 ft deep and artificial mixing is not needed in those areas shallowest areas. Thermal stratification is limited and 'weak' in water less than 6 ft deep.
aka Pond Doctor & Dr. Perca Read Pond Boss Magazine - America's Journal of Pond Management
If you have a rocking piston that produces the higher psi (30-100psi) the 1/2" black poly airline would also be adequate. You can push air from a lower psi rotary vane through 400ft of 1/2" poly (true 5/8"ID) with no measureable back pressure on an air gauge (all open flow). Restrictions and elbows start increasing the back pressure.
Last edited by Bill Cody; 06/08/1407:48 AM.
aka Pond Doctor & Dr. Perca Read Pond Boss Magazine - America's Journal of Pond Management
Well folks, with the help of Bill Cody and the good folks on this board I deployed my Vertex 2 head diffuser tonight and fired up the Gast and VIOLA! Bubbles galore at the pond, and super stinky gas smell filled the air. Only ran it for about 10 minutes thinking I'd err on the safe side. This pond is very old and has dozens of years of muck and decay in the bottom, going to take it slow. One question that I have: I noticed before I turned off the pump that my pressure gauge was reading about 7 psi. I assume this is back pressure? Is this a somewhat normal reading? Reminder: 300+ feet of 3/4 black poly running from compressor to diffuser, 1 elbow from the heater hose to the black poly, the rest of the joints (2 not including the connection to diffuser) are straight couplers.
Many thanks to you Bill, and to the Pond Boss forums. I will post photos of my pump as well as the pond a'bubblin' in a day or two.
