Pond Boss Forums INTRO Questions & Observations Newbie with Aeration ?s

Hi all. Thanks for your wealth of resources. I live in a small community in SW Colorado that has 2 ponds I am in charge of maintaining. We are at 8800 feet and ponds both ice over in the winter. One pond is 1.8 acres and average 5-6 feet deep with deep section at about 9-10'. The smaller pond is just under 1 acre and is fed by the larger pond via dam and spillway.


We have traditionally stocked rainbow and brook trout every year and until recently they always wintered over, with the Brookies even reproducing. In the past we had water rights which allowed us to run 2 water lines year round and kept 2 ice free spots in the winter in the deep section. We recently lost the ability to run these waterlines all winter long so the pond now freezes ovwr and killed all of our fish.

I just got the blessing of the community to purchase an aeration system which will hopefully get us back to where we are, and keep fish alive most importantly.

It's a 3/4 hp system with 3 dual diffusers. I'm curious where I should place each diffuser? In the past the ice free areas were in our deepest part(8-10') but the more I read I see people suggesting that they should be in shallower water 4-6ft deep. Any thoughts or suggestions where each of the 3 lines should be placed? I was thinking 2 deep and one in the 4-5foot range.

Also, I hope this configuration will work year round in keeping a healthy pond. The lower smaller pond wont be aerated until we see how successful the upper system is. Hopefully it benefits from the aerated water flowing from the upper pond.

I'd appreciate any thoughts or recommendations for my system and pond setup.


Thanks for your wisdom and advice.

Aaron

I doubt aeration in winter will overly stress the trout regardless or where you place the diffusers. Trout with winter aeration will live a lot better than trout without winter aeration. Often it is thought that winter aeration in cold climates will 'super cool' the water so it is often suggested the diffusers are placed in shallow water to minimize super cooling the water column. Trout will easily tolerate super cooling the water. In your Colorado case, I think your plan of 2 deep and one in the 4-5foot range" is okay for summer and winter aeration. HOA residents should be warned to keep dogs off the ice so they don't fall though thin ice during winter aeration.

A-aron, welcome to PondBoss from another "trout ponder", over the ridge and down slope from you near Dolores. Sorry to hear your trout didn't make it after you lost the inflow of water.

I keep an aerator going in winter. I purposely have the diffuser placed close enough to shore that open water includes some shallow area near the bank. Last thing I would want to find is an animal or person floundering or worse in the hole out in open, deep water. My trout do just fine without an ice free spot over the deepest part of my pond.

I'd agree with Bill Cody on the diffuser placement for summer. Unless I could come up with some sort of contraption, ramp, float or ladder, climbable mesh, or something else that an animal or kid could use to climb back up onto the ice surface, I personally would not have an open hole in deep water that did not come into the shallows. Maybe you could string the diffusers in a line leading from deep to shallow.

Another thing we do in winter is shovel or plow the snow off some portions of the ice so that algae and other plants can get sunlight for photosynthesis. Do you have vegetation in your pond that could benefit from this?

If you haven't already done so, read wbuffetjr's extensive quest to get his trout to overwinter at 10,000 feet east of us here in Colorado.

Do you ever come down the hill to Durango? We could meet for coffee or whatever.

Roger

Another vote for the comments above. I almost lost my Springer Spaniels because they went into the water after some geese when the ambient temp was -12°F. I have now moved my diffuser and strongly recommend placing the winter diffuser(s) so that there is open water all the way to the shoreline.

Over the years two of our house cats have succumbed to their curiosity about the bubbling water. They walked out on the ice to the edge. One fell in. He had no trouble whatsoever climbing right back up on to the ice sheet. He looked around as if thinking, "Hope nobody saw that."

New Years Day many years ago one of my Aussies fell in when the ice at the edge of the open hole collapsed. After unsuccessfully trying to climb back onto the ice, she looked around and headed for shore. I was already headed towards the pond, coffee cup in hand in my flannel pajamas and house slippers when she made it back on land. It was 2 degrees above zero. She was encased in ice by the time she ran the 100 feet to me.

I was glad I didn't have to take a January 1 swim.

Thanks for the input Roger, and everyone else. We've actually had one of our dogs fall in when we used to run water into the pond. It was pretty scary and luckily we found her shortly after she fell in. Everyone was pretty shook up.This could pose an issue like you guys mentioned. I'm not sure how much water will stay ice free with my new setup. Hoping even in the dead of winter they will overlap and extend to shore. Luckily there are no other dog owners or children in our neighborhood at this time.

We have an overabundance of pond weeds that we struggle to maintain in the summer. Wouldn't be so bad except for the dieoff in the winter and spring with horrible smell and sludge. I'm sure that's whats mainly killing the fish. Good idea to shovel off areas of snow.

I'll have to read the posts about the trout pond above 10000.

Thanks again for the great advice and insight.

Just out of curiosity, what kind of trout do you have in your pond, and where do you get them?

We've been getting ours from Hotchkiss and usually limited to Rainbows, with the occasional year of Cutbows and Brookies.

Cheers,

Aaron

Aaron, right now the only trout I have in the pond are tigers (brook x brown hybrids). In the past I've also had rainbows and browns.
Patrick Goddard at Rainbow Springs Trout Farm south of Durango has been my supplier.

So I setup my system yesterday and tried to get get the 3 dual diffusers in a row. 2 within 10 feet of each shore and one in the middle. Problem is that the further diffusers is approximately 200 feet from the aerator pump. The pump is not strong enough to power all 3 diffusers with valves full open.

For now I have restricted airflow to the closest and middle diffusers, which seems to allow all 3.to run. My only concern is that the airflow will not be sufficient to keep all.three spots ice free in the winter, or very small spots ice free.

Is it better to run only 2 diffusers at full strength, the 3 as is at a diminished setting, or should I shorten the 200 foot diffuser line so that it is only 100-150 feet. Thinking that shortening the longest line will allow the air to be more powerful.

Only problem is that the 200 foot line is the one that goes to my deepest section(approximately 10 feet). So better to have 3 dull blast diffusers in 5-6 feet or water, or maybe 2 instead, one 200 feet out one somewhere else. And if I do keep the long hose section should I try to get the other diffusers to overlap, or far away in other areas?

Sorry for so many layout questions. Just to recap, 3/4 hp rocking piston pump with 3 dual diffusers. Need best layout of line lengths and depths in either 2 or 3 spots. I know it may be difficult without photos or aerial pics, but would really appreciate any feedback. I can provide more specifics if needed.

Thanks

Aaron

aaron, look at the specs for the compressor, then look at the specs for the diffusers. Specifically look at the CFM that the compressor puts out, and the CFM operating range for each diffuser.

If totaling up the max CFM for the diffusers doesn't equal the output of the compressor at the max depth that the deepest diffuser is, then you will have to play with the valves to manually adjust the volume of air going to each diffuser assembly.

i.e. Say the compressor output is 10 cfm at 5 psi. Each diffuser has an operating range of 1-4 cfm. If you are running 3 dual head assemblies, then you'd need a compressor that has a minium output of 24 cfm @ 5 psi to NOT need to adjust the valves.

It's not the length of hose, it's the depth that the diffusers are at. IF they were all at the exact same depth, then the length of hose *might* come into play.

As far as what is best for your pond for adequate aeration then I can't help much but I do understand pumps, compressors and mechanical systems. Essup is correct that if the diffusers were all at the same depth the system would equalize. However, volume and pressure for a gas are very much related in fact the relationship is proportional. Air is a gas - primarily nitrogen and oxygen. As is common since the compressors for aeration systems are on land, the deepest diffuser also has the longest line. Your shorter length and shallower diffusers are preventing you from basically "packing the line" for the deepest and most distant diffuser. The deepest diffuser requires the most pressure and therefore the most volume - the higher the pressure the more volume required to reach that pressure and you have a double whammy because you need more volume to simply fill the line because it is the longest. The diffusers are not really going to have a minimum volume, as long as the pressure is enough to overcome the pressure drop across the diffuser, basically enough pressure to push any air through the diffuser. They are going to have a max volume because they can get damaged if you try to push too much air through them. However, just because air is going through the diffuser doesn't mean it is enough to be effective aeration so i am not saying the volume doesn't matter.

Pressures aren't additive in this type of system. As long as you have enough pressure to get air through the deepest diffuser the system will work. If you need 6 psi for the deepest diffuser and 3 psi for the other two you don't need 12 psi, you just need 6 psi. However, the volumes are additive and your compressor is going to be limited on maximum volume at a given pressure as noted by Esshup.

Unless your system is oversized, you are going to have to regulate air flow to the diffusers to get them all working. If you want to run all three you need to pack the longest line first. Start with the valve open for the longest line diffuser and let it get going. Then slowly start playing with the shorter line shallower diffusers by cracking those valves. It will be difficult if not impossible to get the long line diffuser working if you start with the shallower short line diffusers first, the line won't pack. If you start with the longest and deepest and it won't work then your compressor can't provide the necessary discharge pressure. That scenario is highly unlikely.

Again, I am not addressing your question regarding what is best in terms of effective aeration and your ice issues but from a mechanical and physics standpoint this is just a mechanical system. The volume is critical in order to get the system to aerate effectively, but getting the system to work is about adequate pressure.

I hope this isn't too technical or unnecessary but I find it helpful when I understand what is physically happening. Hope this helps.

Well said MisterA

MisterA always makes great, informative posts, evidenced by his insanely high posts to likes ratio (54:8)

Thanks for the kind words guys - and likes! I worry about sounding like a know-it-all but it really does help me to understand the physics of things so I like to help when I can and I am glad that at least some folks find it useful. I won't weigh in unless I actually know what I am talking about and if I get something wrong it doesn't bother me to hear about it.

Now, if I can only get my fish and water knowledge in better shape I might really be useful.................................

Hell, I don't even technically own a pond yet (hopefully this week it'll be done), but there's enough information on here to make anyone a know-it-all. It's nice to be able to answer some of the questions on here without actually knowing what I'm doing.

Not sure how I missed this post!! Pretty Awesome to have another trout guy and from CO no less!!! One thing I have learned over the years is it is amazing how much easier the water moves around and mixes when it gets really cold. I would hazard a guess that you could turn the third diffuser off for winter aeration and still fully mix the pond. Would be really nice to be able to test that with a DO meter or by drilling some holes and measuring water temps.

This is not necessarily apples to apples. Just some quick high level comparing. I have nine diffuser discs pushed by 1.5hp of pump for 7 acres and I am only able to run pumps 7 hours per day. Diffusers are from 10' to 20' deep. Last temp check water was at ~32.7F top to bottom.