Pond Boss Forums AERATION Systems questions Airstone question...

I have a quite small pond at 100' X 50' X 6' Deep and have a 1/20HP .75CFM pump that I want to use to aerate the pond and also keep an area free of ice this winter. I heard you want bigger bubbles if you want to keep the ice away, so would I be best off not even running the line through an airstone? Or maybe just drilling a few holes in a pipe and making my own?

In the summer I'll be more worried about aeration so I will need an airstone then, but for now if I will benefit more from no stone I'd prefer to save the money.

Thanks for any help. This site is great and if my bank account wasn't already overdrawn I'd heavily consider a subscription.

An airstone works fine for keeping an area open and free of ice.

I use a 50 ft length of garden soaker hose, the black type hooked up to my pump. Works great just use a few bricks to hold it on the bottom.

Interesting concept of larger bubbles maintaining a larger ice free area. Larger bubbles will create more 'apparent' activity at the surface. I'd like to see results from a test of the two diffuser styles. My logic concludes that you will get a larger ice free area from the diffuser that produces the most water flow, which is what is deterring the ice formation; flow or current. The farther the current spreads the larger the ice free area becomes assuming a constant temperature.

Larger bubbles seem to make more activity at the surface but the current or volume flow across & under the surface will be less than with finer or smaller bubbles.
Try the hose only this year and save your money to buy a membrane or stone diffuser next year and compare. Let us know your results. 0.75 cfm will run only one 6" airstone. You will get better results from an 8-10" dia membrane disk. Stones have to be cleaned in acid whereas edpm or rubber membranes can be scrubbed with a brush or scouring pad & water.

Thanks Bill,

Here is the comment from John Longnecker at MalibuWater.com

"Air Diffuser
-- COARSE air bubbles are good for de-icing
-- An air diffuser that releases TINY air bubbles adds more oxygen
for pond water quality. "

Your logic makes perfect sense though, the more the water moves the less ice should be able to form. The problem with testing this out is that the temperature is never stable enough to test duplicate situations. Maybe there is a study that has been done already?

I do have another question...

The pond is about 100' from the outlet. Should I run 100' extension cord, or 100' of air line? Which would be better?

Hondo - Thanks for the large bubble reference. Information sources are always good for reference.
My experience does not always agree with John's comments. He makes comments and usu. does not explain why, or elaborate which to me is suspect. This is a good example of what I'm referring to. He doesn't explain; we are just supposed to believe what he says. Maybe he will explain or tell us why larger bubbles are best for deicing.

Run power cord or airline to the pond???
I prefer airline because this way you can keep your compressor in a building where it has better heat ventilation and protection from the weather; two things, heat & moisture, that are the main enemies of air compresors. Compressor shelters work but are troublesome and more agrivation than a compressor in a bldg. No problem pushing air 100 ft if you use 1/2" - 5/8" ID airline. Cheapest is blk polyethylene water line(cheapest is type for nonpotable water $7.00-$9.00/100ft Lowes/HomeDepot). This will also be adequate (upto 4.5cfm) for a longer life, larger (1/4hp) rotary vane air volume compressor when yours quits. When at the pond w/ your small compressor you can down size to a smaller underwater airline abt. 3/8". 3/8" is not good for a larger airflow compressor; too much friction and head loss.

The only reason I would run a power line to the pond is if you want an outlet at the pond for another reason i.e, fountain , lights, bug light fish feeder, etc. Water and electricity are not compatable; ground fault interupters are not guaranteed. An extension cord to the pond is esp dangerous; be very cautious if using that method.

Contact me when you are ready for a diffuser, I have lots of low cost ideas that are tested and work very good. I specialize in do-it-yourself diffusers and systems.

Thanks again Bill,

You are just a wealth of information, aren't you? I really appreciate you taking the time to help me. Now for more questions...

You mention using the tubing from Home Depot but running 3/8" hose into the pond. Is there a reason I couldn't use the tubing the entire way to the diffuser?

You also mention you have ideas for diffusers. That would be great if you could pass them along to me. I should be getting the pump any day now and will want to get it set up before the water gets too cold.

As for running the hose from the house, that would work great but my problem is how do I get it out of the house? I have a room in the basement I can put it in and run the line from, but would need to get the line outdoors somehow and I'm not sure I want to put a hole in the wall, especially since we may turn the room into a bedroom in the future, not to mention letting the hot air out in the winter.

Lastly, do I need any other equipment for this little setup? A check valve? Will my pump burn out if the line gets clogged?

Thanks again for all your help. I'm learning a lot already and look forward to when I can pass this information on to others.

Hondo you can buy an antenna line feed through from Radio Shack for next to nothing and use it to keep it airtight where you drill the hole. I don't use a check valve on my system and I can always tell when I need to clean my system cause I don't clamp it to tight where it connects to the compressor so if I get to much back pressure it just blows the line off. Has worked out great and only had to clean the soaker hose twice over the summer I just use a brush and the pressure washer and then drag it back into the pond. Bob

Thanks Bob,

I'll have to pick one up. Now just to convince my wife it needs to be in the house and I need to make a hole in the wall.

If I make it go out the wall though it will be exposed to the air in the space between where it comes out of the house and where I bury the line. Will this cause it to freeze up?

It might if you get real cold where you are, I would just get a piece of pipe insulating foam and cover the tubing. Should do the trick.

Hondo - No problem of using 1/2" all the way to the diffuser. I run one of my diffusers w/ a 5/8" dia garden hose which you may already have an old one you can use or the neighbor is discarding. My other diffusers use heavy duty preweighted airline. I assumed you already had a system w/ an airline already in the pond. Many weight the airline to the bottom. If you use 1/2" blk poly it will take 0.5 lb /ft to hold it on the bottom. a brick every 8-10 ft is commonly used but I find this is the most troublesome later on. Common problem, be very caucious of kinking the airline. Kinked airline will cause nothing but headaches.

Alternative to compressor in the house - consider getting yourself a doghouse or large Rubbermaid tub w/ lid or something large to house the pump in. Put some foundation vents in the side and largish holes in the bottom with window screen over holes to keep bugs, wasps, etc out. Set it up on bricks or blocks so it gets bottom airfow and heated air rises out the vents.
Compressors in the basement have to be guarded against condensate water draining back into the pump if it is shut off. I often use a water trap to collect & drain concensate water in basement units. Depending on the goals of the aeration, often they do not need to be run all the time. Compressors have bearing lives (in hrs) and in a small pond like YOURS constant circulation is not necessary. Extend the life of the compressor 3X-5X with less run time. Why are you aerating? Ducks, fish? oxygen?
For discussion of run times in MI winter see my Sept 06, 02 post to CT under topic: Should I Aerate? CT's post/question: Should I aerate All Year?

QA check valve is important if: 1. You run the system intermittently or if your compressor develops only low pressure and airflow blockage will damage the unit. To prevent damage to the compressor I encourage use of an adjustable pressure relief valve ($20). Bob K's idea works for pressure relief; don't clamp hose or not too tight to barb fitting . It is better if you have a cheap low pressure guage (30psi & $10-$12)to monitor the sys. and also trouble shoot any problems. However cheap guages are sometimes a problem w/ pulsing compressors.
I prefer check valves without springs ($8.00). Springs underwater often cause problems once they are corroded or clogged.

Your pump should have some kind of air filter, internal dirt tends to prematurely wear out compresors. Hopefull your unit come w/ one. Keep the filter clean! If it can't get air it can't blow much air.

I will reserve supplying information on homeade diffusers till next year. I want you to use John L.'s big bubble idea first. Let's test his statement.
Nose trouble: how much did you pay for 1/20hp 0.75cfm? Stoney Creek?
Did I get all your ????'s

This is great info. My questions are almost the same, just a different situation. My pond is about one acre, and 600 feet from the house. What size hose (pipe?) and compresser should I use?

Bob K. A Factoid Hint. I have a pondowner that cleans his soaker hose annually in the bath tub with clorox bleach; says it works good. Bleach or acids suchas muratic or vinegar have also been used. These are important do dissolve the mineral/carbonate buildup in the pores. BC

Bill,

For the 1/20 HP approx .75 pump I went with a Gast model MOA-175-AA pump. I got a new one off E-bay for $55 including shipping, a filter & the outlet plug.

I'm still not sure where I'm going to put it, but so far I'm leaning towards a spot between the rafters at the ceiling of the basement so it can run down-hill the entire way but still be inside. I really want to keep it inside so it lasts as long as possible.

I would rather not test out the big bubble theory as I have nothing to test against. Even if I tried big bubbles this year and small next year the temperature wouldn't be consistent so I wouldn't be able to draw any conclusions....that is unless someone wanted to give me an additional $75 for another pump, line & stone in the interest of science.

Anyways, if nobody wants to donate a pump to me for this "scientific" study I would prefer to start with a diffuser since the pond really needs as much air as possible (no flowing water) and that is almost as much of a concern as the ice freezing.

Thanks again for all your help. Hopefully I'll get a chance to call Home Depot and pick up a couple bundles of tubing.

Hondo,

Trust me the small air bubbles will work just fine. Of course the deeper the diffuser the better it will work. However do not put my diffuser(s) in the deepest water in the winter. I set them off to the side as I do not want too vigorous of mixing of the water column. I have found that can stress warmwater fish which seek the warmer water in the deepest part of the pond (relatively speaking).

Thanks Cecil. I'm hoping to convince Bob to tell me his plans for a cheap diffuser.

I tried Home Depot and didn't have any luck finding a black poly hose. According to Lowe's website they have 1/2" hose that sounds like the same thing for about $8/50ft. Would this be what I should be looking for? Here is the address:

http://www.lowes.com/lkn?action=productDetail&productId=71217-1029-MLT71

Otherwise I can probably get some cheap 1/2" air hose in the black poly too if I call around.

I have used that hose in my greenhouse works great and they have connectors to attach 2 lengths together. The other type is in 100 ft rolls in the plumbing section I use the 3/4 inch in the greenhouse to circulate hot water for radiant heating and it also is great about 15.00 per 100 ft it is a little hard to work with unless you run hot water through it and get it straitened out, it likes to recoil itself.

Bob

Great idea on the hot water to uncoil the hose. I have a hot water line in my garage and I can run the hose right down the driveway and get it straight. I'll check in the plumbing section tomorrow and see what I can find.

Oops, I meant I was hoping to convince BILL to tell me about the cheap diffusers.

I went to Home Depot and they had the 1/2" poly tubing that Bill mentioned. Only $8 for 100ft. You have to get it from the plumbing dept though.

Now for some more questions...

If I am running a 150' line off the compressor does that cause me to lose significant CFM? I tried it in my sink using both a 2' piece and through the 100' piece and didn't notice much of a difference.

We tested the pump in the basement and the wife informed me it sounded like someone was using a jackhammer down there. I now am left with putting it by the house, but outside, or by the pond. What are the major problems with running an extension cord out to a spot closer to the pond? People have cords out during the winter running their Christmas lights...

Also will running an extension cord increase my electric bill, or would it be the same?

Thanks again for all the help...oh yeah, Bill asked what I wanted the aerator for, well it is both to keep a hole in the ice so I don't have to provide water for my ducks and to aerate the pond as I have way too many ducks for the size of my pond, but like them anyways.

Phil in CA. Pond depth where diffuser/diffisers are located is important.
Long airline runs deal with at least three variables; pressure, air volume, CFM and tubing diameter. If you are using a low pressure 'pump' then pressure loss becomes important because you want enough pressure when finally ariving at the pond to continue to push down to the bottom and release air. From your post I assume you don not have a compresssor yet. Two main options.
1. Low pressure (10 psi) high air flow (4.5-5 cfm)rotary vane pump 1/4 to 1/3 hp will work but you will need 3/4" airline run to the pond. Then under water you can go to 1/2"-5/8" (5/8" ID better) . 1/2" is only good for abt. 400ft. before you start to lose psi. due to long tubing distance.

2. Higher pressure pump 20-50psi. Piston, diaphragm or roc-r-arm. All are noisier than rotary as Hondo above found out. He wouldn't have heard the rotary upstairs. 100psi is too high not needed. Plenty of excess pressure for pushing air thru small tubing 3/8"-1/2" for 600 ft. , but low cfm and thus fewer bubbles. Fewer bubbles means smaller diffuser and maybe only one diffuser and quite a bit less water movement.

Did I answer all the ???? More???

Hondo - I'll see if I can get all your ????
Good price for the pump!
150-400ft 1/2" tubing no problem for your pump.
NOTE: the 1/2 blk poly from Home Depot is true 5/8" ID not 1/2" as printed on the skin.

Extension cord will work to the pond but it is dangerous esp with snow and melting & rain water. By all means plug the damn thing into a ground fault plug. Be careful your wife may be a widow (let her know I'm single & looking!). And you might get some fried duck if there is a short.

I don't think the extension cord, if proper guage wire, will cause any extra electric usage.

For aeration of your small pond for ducks , it won't make a big difference if you use air just out the tubing or add a diffuser. AS Cecil said "Trust Me". I still would like you to try just tubing this year. This way you will also get a better idea of the benefit of a small bubble diffser. The winters may not be the same this yr and next yr but there will be enough temperature variation to get a good idea how big the open water area is at different temps, just estimate the opening size
and record the temps. If you use just tubing tie it to a brick or two so that when the air is on the tubing end comes up (rises) off the bottom about 14"-20". Don't release your air close to the mud/muck.

With duck fertility in the pond and an open water area present there will be more than enough phytoplankton activity in the water to keep your oxygen levels quite high all the time thru winter. Bubbling activity will have very little impact on the over all pond oxygen levels. Phytoplankton are doing most of your oxygenation!
Did I get all your ???

Bill,

You got all my questions, but of course I now have a new question.

One of the benefits of some of the bubblers I've seen is that they don't let the water flow back up into the tubing. If I leave the end open won't the water fill the tubing at least up to the water level? If the water fills the tubing it will be more likely to freeze and stop the air flow possibly burning out my pump.

I'll do my best to record the temperatures at which the pond freezes over and the size of the opening this winter using the open end. Then next year I'll try and compare that to when I have a bubbler. I still think someone should donate some money towards this project in the interests of science so I could get a second pump and test them in identical situations.

I'm pretty sure the plug is a ground-fault plug, but I'll make sure. Isn't it required in outdoor plugs on newer homes? Our house is only a few years old. I am also planning on using the plug that is connected to a light switch inside so whenever I am dealing with the pump/plug I will turn off the switch so there won't be any current. I'm not letting the wife collect the insurance policy THAT easily.

By the way...

Since Bill mentioned that was a great deal on the pump I thought I'd mention there is another one available that the auction will close in 2 days. Just go to ebay.com and search for "gast diaphragm" and you'll see it listed for $39. $15 shipping and mine included a filter from the same person. They were very easy to work with and got me the pump pretty quickly.

Hondo - YES you will need a check valve on the end of the hose - good thinking. I took it for granted and assumed; both bad ideas. Don't get a check valve with a real stiff spring, better w/ low tension spring or no spring. Water draining back up the air pipe to the water line & then freezing is ONE VERY GOOD REASON NOT TO: RUN OR AT LEAST SHUT OFF YOUR COMPRESSOR DURING WINTER. A frozen ice plug in the air pipe causes big time problems that usu damage pumps. They are not designed to with hold their air. That is why I recommend a pressure relief valve that will allow the air to escape and not harm the pump if any type air block happens.
If you don't shut your pump off during winter no problem; providing no power outage.

Your outside plug should have two small buttons on it 'test' and 'reset' if it is GFI.

How you going to hold your airline on the bottom? Many use 10 ft sections of rebar/rerod abt 1/4" -3/8" dia or stranded cable. It has to weigh abt 5 lbs/ 10 ft of length..

Easy way to install your 'bubbler'. Strech the airline out full length along the pond. Tie a heavy non-rot cord (sm rope) to the weight/end. Walk around to the other side w/ the end of the rope and drag it in. You may have to add a temporary extension on the rope to get around the pond. Leave rope atached all winter; use it to pull it out in spring or as needed. Simple, very easy & no monkeying around in a boat pulling weighted airline. No float needed; know where bubbler is by leaving it 'on' during installation.

What's next??

Bill wanted to add that I use a 2 ft section of 30 pound mono between the end of my bubbler and the nylon cord I use to pull it into position then all it takes is a good tug break the mono and pull the nylon out of the pond. Works out real good for me.