Pond Boss Forums Thread Like Summary - 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

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.

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.