Pond Boss Forums AERATION Systems questions How to setup Winter diffusers for Trout???

I would like to hear some input on how to layout these diffusers for Winter. All diffusers close together to open one hole as big as possible or spread out to open a few smaller holes?

How many fusers do you have? First thing I think of is your size of pond and how cold it gets their. If I were doing it I would put 2 fusers together and divide it out in 1/3 lengths and have 3 stations to cover more area. Or if your only using 1 fuser but do the same thing.

If you can afford it... I would put in as many as you can handle. lol in about that 3 to 4 foot depth. Keep that baby opened up!!!! If you can do that then your on your way I think!!

RC

I am planning on running a little 1/3HP motor with a Gast 0740 this winter. Should be making ~5.5 CFM at 2 PSI. Sooo, I could do 3 spots with dual vertex stations or maybe 5 single stations?

That leads me to an additional question. 3 duals or 5 singles and spread out or together.

IMO your pond is large I would do at least 3 spots. Cause your probably only going to open an area about 20 ish feet in diameter maybe give or take. I'm not sure I don't do winter air so not sure on how big a hole you cam make.

I would think if you can power 3 duals effectively I would do 3 duals if I remember right your pond is long so I would do my best to put one in center and then go left and right as much as I can with the other 2 setups. I would think that would leave you nice 3 spots for them fusers to do their job.

The other thing that scares me about your situation is possible line freeze stuff like that. So having 3 spots would be good in case one ends up not working right. I hope it works for you that pond is awesome and your land their is very cool!!!!

RC

P.S. I am no expert when it comes to winter air though so lets see what others have to say.... I don't want to steer you in the wrong direction.

Thanks RC!

I am not too concerned about the lines freezing up. Maybe it'll be a problem, but I don't think so. I've got the main air line buried 18"-24" deep and the manifold box is buried right up to the rim of the lid. Believe it or not, the old water line for the cabin was only buried 4"-6" deep and never froze! We get fairly deep snow up there before the really cold temps come on. The snow insulates the ground and keeps the frost line from going all that deep.

I am going to see what the consensus is here and then order the diffusers.

Oh that's good then!! Very nice! Yep your on your way man.

RC

5.5cfm will supply 11 diffusers at minimum flow

Since the minimum is just that, and there is no margin for error at that level, I'd go with single diffuser disks, and a maximum of 10. 2 psi is 4' water depth. Now, what the people aren't thinking about is how much air line this will take........ Each diffuser disk/airstation has to be at exactly the same depth as others on the same line, or you have to run line from a ball valve to each diffuser disk/airstation.

Case in point. I have 5 2"x12" air stones in Intex swimming pools to hold fish. They are powered by a regenerative blower. Low psi, high volume. If one air stone is 4" deeper than any of the others, the air coming from it is almost nonexistent. I have one air line going to each swimming pool, then around the top edge. The air stones are "T'd" off of that airline.

If it was mine, I would put 4 single disks in one area, making sure that they were the exact same depth, and placed 30 to 40 feet equidistant from each other. That way, if each one opens a hole 30 to 40 foot in diameter, then all the holes will be touching and it will be one big hole. If you think the ones last year only opened up a 20' diameter hole, then place them 20' from each other. I'm not used to running winter diffusers at minimum or close to minimum flow, so I don't know what size hole they will keep open. The wave action from the boil hitting the surface will help keep the ice at bay too. So, maybe 2 sets of 3 diffuser disks each to get more wave action?

Move down a ways (as far as you dare) and do it again.

Thanks Esshup. I do have the manifold in place and it actually has 10 ball valves coming off of it. Some of those will be used up for the deep water stations but I still have 5 or 6 available valves.

I will also have the windmill diffusers to work into the mix.

My thinking is to space them far enough apart to make a larger hole to avoid a snow bridge keeping it closed to the sun.

+1 on that...

I cannot do a setup like that and have the hole in the middle of the lake without it being in at least 8' or so of water. To do a setup like that and have it in 4' of water it would have to be on one end or the other and pretty close to shore. Would it not be a problem to have a massive hole open on one end of the lake and nothing open on the other?

OR have a group of 3 on one end and another group of three on the other end and nothing in the middle.

I am concerned about having a big dead spot - no pun intended!

I'll send you an e-mail with pictures tonight to show you hot to do it where you want to do it.

You want the winter diffusers 1/3-1/4 the total pond depth to leave a warm water refuge for the fish.

10-4! Thank you!

1/3 to 1/4 of total depth would put me at 5-7' so may not be able to run as many.

I think with trout you do not need a warm water refuge. Highly oxygenated water throughout the entire water column during winter ice & snow cover is much more important for trout than keeping water near 39F. Trout survive just fine in streams that form anchor ice during winter. This water ranges from 33F to 32F or less. That is one of the reasons why they call them cold water fish.

From my tests of water temperature during winter aeration under ice and snow cover, mixing of the water column extends a whole lot further than the immediate area surrounding the open hole. Apparently the movement of cold water has a lot less resistance to mixing than the warm water of summer. I don't know how to measure how much less resistance to mixing, but the under ice water movement from a diffuser is impressive. It must be related to the physical properties and density of water as it changes temperature. If you operate one diffuser (1cfm) for 4-6 hrs per day near the bottom at 12-16ft deep, I predict this one diffuser will mix and circulate oxygenated water to 0.7ac to one acre or more of water. Thus 4 single diffusers equidistant in 1/2 of the 8 ac will mix 1/2 of the 'lake' even though each open hole is only 20-50ft dia. If you don't have water deeper than 10 ft then place diffusers along at least 1/2 the length of the belly of the 8 acres. This should provide enough oxygenated refuge to allow trout to survive the winter.

Are you able to go up there during mid winter and make some temperature and DO measurements?

Advanced Reading: Not all ice forms on the water surface. In streams, the turbulent flow can allow the water column to supercool to temperatures below the freezing point (0C-32F), allowing ice to grow in the water column. The first ice to appear is frazil (small disks or spicules of ice suspended in the water column). When turbulence transports frazil to the river bed, the frazil may stick to the bed, forming anchor ice.
Frazil and anchor ice are most likely to form on a cold, clear night when the wind is strong, the humidity of the air is low, and the river is at minimum flow, especially if such a night follows a cold, windy, cloudy day.

Commonly recognized types of stream ice include frazil ice, anchor ice, surface ice, and snow or slush ice. These are distinguishable by their characteristics and origins, and it is common to find all four types present in some combination along any mountain stream. Formation processes of these ice types are strongly interrelated and dependent upon each other.

The accumulation of frazil ice on underwater structures is known as anchor ice. On stream bottoms, it appears as smooth, white pillows. Anchor ice is typically a spongy, flocculent mass of ice crystals that is more porous than ice that forms on the surface. With time, patches of anchor ice may grow horizontally and join to form a continuous carpet of ice on a stream bottom. Maximum anchor ice thickness was about 30 centimeters and average thickness was about 8 centimeters in a Michigan trout stream (Benson, 1955). Anchor ice formation is usually highest during cold, clear nights, when heat loss from the water is greatest. In streams, anchor ice occurs most commonly on gravel and boulders in riffle areas where flow is most turbulent (Benson, 1955). Anchor ice seldom forms on substrates of fine sand, silt, or clay because (1) the anchor ice can lift free before attaining any significant size, or (2) streambed heat flow to the water may be effectively greater in these areas than gravel or rocky areas (Ashton, 1986). Wigle (1970) reported temperatures of 0.4 to 0.5°C at a depth of 10 to 20 centimeters below the bottom of the Niagara River, while temperatures of the water were supercooled, indicating the potential for surface heat transfer to water. Anchor ice may form on stream beds when turbulence is strong enough to transport supercooled water to the bottom, where ice crystals may attach to the bottom and further grow (Ashton, 1986). Anchor ice generally does not form when a surface ice cover is present.

Wow that is very interesting, Bill!

I couldn't guarantee it, but I could possibly get up there and get some measurements. Physically it's no problem. I could get a ride up the mountain. Would just have to make a trip out there.

It doesn't have to be high altitude Colorado. Any person with winter aeration in a safe ice and snow covered larger pond can make the measurements to verify what I am saying. Make the water temperature and DO measurements to verify. Then report your results back here.

I understand. I will do my best to contribute.

Bill I just saw your additional information. Thanks so much for all the insight!

My water mixing "theory" is not proven in numerous different pond settings. If you live where ponds have significant winter ice, you aerate and you have a DO meter take some temperature and DO readings to verify that cold water mixes very easily. One main thing that has not been tested is how far the currents will spread from action of one diffuser.

Bill, you are correct, I keep forgetting that it's a trout only pond (in regards to the water temp during the winter).

My one concern is the possibility of having a bridge of snow form over the open water if the diffuser only opens up a small hole.

My concerns could be unfounded though.

Thoughts?

What do you guys think about this?

Here is what I am thinking of running for Winter stations. 5 stations at the discussed depths should put me just under 1 CFM per disc. The circles are diffusers ran by pump off of solar. Two side by side circles are an existing dual station I could just keep running in place for winter. The W is an existing single Vertex ran by a Koenders windmill. The WW will be a dual Vertex ran by an American Eagle. The SE corner of the lake is the deepest at 20'+ so only air in that corner in the Summer.

A pleasant surprise from this post is it seems that since I am dealing with trout maybe I do not need COMPLETELY different diffusers for Winter/Summer. I should be able to run ALL my stations with the bigger pump in the Summer and then just cut the number of open stations back some when I switch over to the smaller pump for Winter.

Heck of a setup. How ever I don't think you need to go all the way over to the other side of your pond from your dock with the one fuser. I think you could put that one right in front of your dock maybe just off to the right or left to keep that area opened up bigger. It would make for a much shorter run and still get the job done... but that's just me....

RC

I would move the W diffuser down so it is a little further down and below straight between the o - oo. Then move the upper O to almost or mid-way where the W was located ( 1/2way between where the W and O is proposed). I don't think a diffuser in front of the dock is needed and will be wasting needed circulation in 8ac (within 80ft of the dock is too close to your dock - IMO). For your goal, you want deep water circulation, not shallow water circulation. What is the distance from the dock to the upper(north) shore? The O should be above mid-way between distance of the width. In 39F water, this should push water to the north shore with the help of o & oo. When W and WW are working in winter each should push water 200ft from my experience and temp-DO measurements.

Like this, Bill? Do you agree with only running air in the deepest water (20'+) during the Summer or should I rethink that?

Hard to get an exact distance from dock to far shoreline as Google Earth hasn't updated since 2014 so the new water levels are not shown. A close estimate is 450' from Southern shoreline to Northern shoreline.

Sorry WB if I am stepping over you post here but Bill could you please explain to me and or WB on others why deep water circulation is his goal?

I thought the goal of winter air was to just keep the shallows open between 4 and to 6 feet for sun penetration and taking care not to super cool your water but still have some circulation? Just asking why is his goal different? Is it because of the trout I guess?

Thanks,
RC

I will let Bill clarify but I took his response to mean that because WB's pond is a trout pond, and since they do well in cooler water, that having that cold water during the winter wouldn't make a difference to them, vs. making a difference to say LMB and BG/RES.

I explained in my first post why winter deep water aeration was good for WBuffet. Go back and reread it. 'Supercooled" water does not harm trout; at least nearly as much as it stresses warm water fish such as LMB, BG and especially RES.

I like the diffuser setup in the 2nd picture better than the 1st setup. For the trout application we want good mixing and circulation in the main basin and the cold water currents will spread far toward the edges. Plus with diffusers in the deeper water, the boils at the surface will be stronger due to more depth for the rising column of bubbles. Stronger boils will move water further toward the edges. I think the 8 ac could be completely mixed all winter with daily solar operation with the current setup. Large volumes of water rising from the bottom has to be replaced. Replacement water comes from the edges, travels down the basin toward the diffusers. Extensive mixing occurs. Similar extensive basin water mixing occurs in winter-spring water shorline ice melts or the areas under the ice become warmed by the sun. Water temperature-DO tests mid-winter would be very educational in this application of winter aeration.

Daily aeration will keep fairly large holes (40-60ft) open in the ice. The open water and resulting phytoplankton photosynthesis and daily bubbling action will diffuse air into the water and oxygenate a lot of water and the currents will push this far from the diffusers probably to areas at least 400ft or more in dia from the boils. I have seen a windmill with a 20 ft open ice hole push oxygenated water 200ft under ice-snow cover.

WarrenB - My current version of Google earth allows me to measure distance at a location - map. My G-map had a tool bar at the top with a list of icons. One of them right of center had a ruler. Click on it and choose options in the window. Measurements were pretty accurate in my distance tests. If I knew the address or location of your pond I could make the length, width, & area measurements.

http://mashable.com/2014/07/09/google-maps-measure-distances/#c55mTqPsluqw

Yeah sorry totally missed that post... my bad.

RC

Bill - I feel like you just dropped some huge information bombs for the handful of Trout guys that are on Pond Boss. If not for this thread, I would have just went with 4-5 diffusers in 4' or so of water like I have read so many times without ever making the connection that I was doing a "bass aeration setup" for Trout.

I think I am going to edit the title to replace "8 acres" with "trout" so any trout folks can find this critical information easier.


I use Google Earth Pro and often use the measuring function you are talking about. The current image is an old one and does not show the new waterlines from the increased depth. I am just measuring the distance on Google Earth by estimating where the new waterline is. I come up with 450' from the dock (has been replaced by a dirt peninsula) to the South shore.

Ok folks, got a little more data in and just wanted to post here as well.

As of 11/05/2017 water temp was 37.9 from surface to 20' deep. DO has increased to 8.7 PPM at surface and 8.3 PPM at 20' deep.

One question that may sound silly, but I am semi concerned....

We haven't even gotten into the serious cold yet up there. Coldest temp so far is somewhere in the 20s and we are at 37.9 degrees. What will the water temp do when we regularly start seeing 0 degree days? What are the chances of me freezing the lake solid?

Just don't ever turn the aerators off!!!! You will make that water so cool that the least interruption in bubble action will produce in instant pond wide total freeze like going into a blast chiller!!

I'm kidding of course but have a vivid visual on watching that whole 8 acre pond go to one solid ice mass in an instant due to temporary solar power failure

It is a good question. Bill said that trout don't mind 'supercooling' but if the whole pond is super cooled and there is no slightly warmer water ANYWHERE, what is to keep it from suddenly icing up?

Canyon - haha! All jokes aside, I am slightly concerned.

Anyone else have any thoughts on this? What's the coldest water temp you think it will reach up there?

d

Bill D I wasn't thinking of the problem in terms of altitude other than how the altitude affects the temps the lake will see. I am wondering what kind of water temps are possible when the air temps are 0 or below assuming we are still fully mixing the lake.

Just got an update today. The lake is already frozen over and the diffusers are keeping lots of open water.

d

It will be interesting to see the water temp at the bottom of the pond in a month.........

Unfortunately, I am not sure I will be able to get a temp reading in a month, Scott.

I THOUGHT I would get a temp/DO reading last year when we were out there for Christmas.... What a joke that turned out to be. Coming from Atlanta, 4'-5' of snow created problems I wasn't prepared for. Just walking, even with snowshoes, is a hell of a workout in that kind of snow at 10,000'. I strapped on the snow shoes and walked down to the lake with a 6' piece of rebar to see what kind of ice I could find. I walked out onto the peninsula and started poking around looking for ice. All I could find seemed like slush. I NEVER did hit anything solid like ice so I was scared to walk out off the peninsula. So then I was going to drag the boat out there, get in the boat to get out a little farther and poke around. I turned around and started trying to remember where the heck the boat was and realized I was going to have to dig a bunch of 4' exploration holes in the snow to find it! Not to mention how much the snow shoes were complicating all this. Then I realized, first, I was going to have to go back up to the cabin to get a shovel. That was it, said screw this and gave up on getting the data!