I'm thinking of setting up an aeration rig for my 1/2 acre pond with the deepest part at 15' max but planing on installing 9" fine bubble membrane disc diffuser about 2' above as not to disturbe the mud at the bottom

The pond was built 4 years ago in a valley, draining about 60 acres, not a spring fed.

After reading countles posts here, as well as sales websites, I came to the conclusion that rotary vane is what I need. I'm looking at a couple GAST rotary vane 1/4 HP - one for $90

http://www.surpluscenter.com/item.asp?UID=2007070723333121&item=4-1540&catname=air

and another for $375

http://www.drillspot.com/products/35791/Gast_0523-101Q-G582DX_Vacuum_Pump

The $90 cought my attention. Will I be getting what I pay for with the $90 pump or is this my lucky day. The specs are similar though.

Any thoughts will be much appreciated.

$90.00? Sounds too good to be true.

I question the statement "so as not to disturb the mud at the bottom." I have diffusers laying on the bottom in all four of my ponds and I have as of yet to disturb the bottom. If you do it right there should not be a concern. Additionally I would not want my diffusers above the bottom as this could leave an anoxic layer IMHO. Maybe the experts can chime in.

$90 sounds too good to be true to me too. I believe it was a 220V pump, which I never researched though.

Wouldn't the bubbles pull the anoxic layer to the top from only 2' above the bottom? They sure move a lot of water. My system is about a foot off the bottom in the deepest part of the pond(NE Texas).

I think I'll go with $375 pump with 2 9" membrane diffusers set through 1" poly tubing (about 60'). This should keep the rig under $500.

Also I'm interested in a 230V timer. Mechanical or digital? That is the question.

Thank you all for the imput. I'll update this thread with the progress of the project. It will start in a week or two.

Could be but I'm no expert and haven't raised my diffuers to know. All I know is why raise them and take a chance if you don't have to? I raise bottom oriented species (yellow perch) and want them to be able to utilize as much of the pond bottom as possible.

Bigbamboo, why would you spend time to look for a bargain, then not take it? Looks like the same specs on the pump. Lots of these pumps are just replacead by newer models, but all you want to do is move air.

burgermeister===

Just ordered the $90 pump (the greed got the best of me) and a couple of odds and ends. Also 2 9" round membrane defusers $16 each + $11.24 shipping. So far I'm unter $200. Will use 1' poly pipe and weigh it with something original, don't know what just yet.

Will keep in touch.

BTW my max depth is 9'(actual measurement) with an average 6' for the whole pond.

You can attach rebarb pieces available at the local building supply store with electrical ties.

BigBamboo,
I am very curious as to where you got your 9" membrane defusers for $16. That's a great deal. Thanks.

Shure Bob. The once I got are the third item down at the following link.

http://www.diffuserexpress.com/catalog/flexair_threaded_disc_diffusers.html

Don't ask me how good they are, coz this will be my first aerating rig. So, eithe take a chance like me or wait a couple of weeks when I expect to get my rig setup and running and I'll let ya know how it turned out. However,I wont be able to compare to any other once since I never used any. I'll be taking pictures as I go and if I figure out how to upload them, I will post some.

Best of luck friend.

Cecil Baird1===

Yes Cecil, that is an option but I think I'll go with what's available. Just so happens I got a stack of deliniator (sp) posts cutoffs, 'bout foot in lenght. They are like "U" shaped, so the 1" pipe should feel right at home after I tie'em with some electrical tape or duct tape, whatever ist available.

Thanx for the tip friend.

The $90 pump looks like it is missing the "pump" on the end of it from the picture (comparing it to other pictures of the same model). Could you let us know when you get it if the pump is with it?

CWJ===

I don't thing it's missing anything. The reason it looks like it's missing "the pump" is because it is not a standard GAST pump, but rather manufactured by GAST for one of their customers for specific purpose that doesn't require an intake ane exhaust filter, thus smaller pump housing. It takes the same vane rebuilding kit as the other ($375) pump. This info is from GAST discussion forum by one of their own technicians.

I did buy a $5.99 intake filter to go with it. Do I need an exhaust filter as well? Can't think of a reason why.

Will be able to tell a better tale when I get it, should be this coming Saturday.

Till then my friend.

If you ty wrap the rebar, bricks or whatever...warning. Make sure is is very securely made fast to the poly with rubber between. Otherwise, the vibration of the pump will cause pin hole leaks. If this sounds like the voice of experience, it is. Next time, I will buy weighted hose, or possible fill pieces of garden hose with sand and tie to it.

Yep weighted hose is the best way to go Burgermeister if one wants to spend the money. Weighting down hose is a pain in the ***. Addtionally non weighted hose can get kinks in it vs. the newer stuff.

Bob V and BigBamboo,

I've been using 9" disc diffusers from Diffuser Express for two years now. No problems to date.
If you are interested they do make diffusers with 0.5 mm slits as opposed to the 1 mm slits. When I ordered, I had to ask for the 0.5 mm diffusers. They may be standard now.

The Pond in question



BigBamboo

I'd have recognized you anywhere!

The pump from the surplus center is missing the standard quiet running head or chamber. Expect this pump to be quite noisy or rattle sounding, plus it is only for 220V operation.

...update

Got the diffusers but the pump won't be here this weekend, bummer.

Since I already have a shop compressor, I've decided to procede with 15 minute thing so it'll be ready for full duty next week.


Here are the deffusers...
1mm slits, I think.


Installing the PVC...




Decided on a temporary setup using a reducer
to use a temporary 3/8", $21 air hose till I get the 1" permanent setup. I need an extention air
hose anyway...


Had to convert my tyre inflator to keep
the pressure at 5 psi. Pressure regulator on
the compressor only goes down to 60 psi...


Finally the results - a nice, stinky boil.


I'm glad I got this show on the road, coz my cat fish has been gasping for air. That's not a good sign for a bottom fish.

Will keep in touch.

A nice stinky boil.

Thanks BigBamboo, Beautiful pond you got there. I'm going to order me some of those diffusers you got there. Good job on the pictures. Thanks. I think I need about 12 more diffusors to do it correctly. Here is my little piece of heaven:

http://www.rvanorman.com/gallery.asp?folder=lake

These photos were taken a couple years ago so the weeds are fairly previlent. I have been aerating for about 2 month now. Trying to clean up the muck on the bottom is my goal. Anywhere from 1 to 5 feet of the stuff. The weeds love it in the shallow water. But just in the 2 months that I have been aerating the water clarity has improved tremendously. Thanks for the link to the diffusor company.

...update.

The pump is up and running on a temporary basis until I decide on a housing. It was a little noisy but it quited down a lot after it was hooked up to the system. Now I can't even her it running from the deck, approx 30' away. It runs at 230v and consumes 1.3 amps, that gives it an effective rate of 300W, or $0.03 per hour at $0.10 per kilo-watt. It runs at 4.5 psi supplying 2 - 9" diffusers. The pump housing gets rather hot especialy the exhaust manifold, but the motor is luke warm. I just didn't expected that much heat at 4.5 psi.


And now the bad news...

A day before hooking up the pump, I was doing that 15 min. thingie useing my 25 gallon shop compressor, slow pumping about 4 tanks a day from 120 psi down to 0 psi(don't know how many cubic feet that would produce at 4 psi), then for whatever reason I pumped 3 tanks at night (from 20:00 till midnight... the next day desaster! dosens of catfish dead and a few bluegills. I guess my pond was in a worst shape than I thought. Anyway, I pulled 4 wheelbarrows of cats out of the pond and buried them in the garden in a shallow 2' x 30" ditch. Maybe I can get a good garden next year so it won't be a total waste. This is the last load when I took this picture. The other once were full to the bream. What a shame.

Big Bamboo,

Sorry for the loss of the fish.

I hope this makes the point for owners that want to use areation how important it is for a good oxygen meter and start up procedures.

Bass Pro has been carring a good quality O2 meter endorsed by Bill Dance for a while. I would suggest everyone that is serious about their pond get one.

Heck if you had $150 fish in an aquarium you would have a test kit for it.

Again, sorry for the loss and I hope everyone takes note on your experience.

BigBamboo, always sorry when this situation happens,Any chance the "oil type" compressor in the shop added to the problem. I seem to always have some oil residue in my shop compressors when I drain them yearly along with a lot of foul condensate.Be sure to match the diffuser to the output of the pump and get a lifting rate on the diffuser at your intended depth so you arent lifting too much water which can diffuse the upper DO down to a lethal rate.In a mature pond that has a high demand for O2 consider placing the diffuser in a depth 50% of the maximum or intended depth during startup and taking it deeper each week, especially this time of year.This may be safer than (from a depth standpoint ) all or none.

...update.

The worst is over. So far hadn't had any problem with the fish dying on me. The pump eventually ran 24/7 for two weeks even though the highs were in the range of 99-107' F. By the end of second week, the pond was covered solid with scum. (see pic bellow) It looked like it has frozen over. Last week whole that scum disappeared, mostly due to some high winds wee had. The foul smell is also gone. Currently I'm running it at night only - from 21:00 to 07:00. So far, so good.



So far I can recommend the hardware in this project to anyone in similar situation. If anyone has any additional questions, I'll be happy to answer.

I'm thinking about buying 2 more diffusers and make a square configuration (about 2.5" x 2.5") with the idea of having a wider boil, even though it won't be as intense. I want more aerating and less water mixing. So, what do experts think you think, is it a good idea?

To: Ted Lea FOREVERGREEN. My compressor is oil-less. The problem was caused by aerating at night when DO was in short supply, plus the toxins. However the croppies and the blue gills were fine, but most of my catfish is dead. I only see a few smaller cats at feeding time.

To: Cary Martin. Know a good place to buy one and how much they go for? It may be a good idea to have one O2 meter around. Thanx.

You can always go with a pond aerator or fountain unit depending on size or pond and budget. Give us a call or visit us @ http://www.boatcycle.com