Pond Boss Forums INTRO Questions & Observations Any Danger Starting Aerator To Melt Ice?

I remember reading something in here about being careful not to aerate too much when first starting up in the Spring, as the aerating will bring up too much bad water all at once and harm the fish. Is this right? I would like to start my aerator now to melt the (rare, Oregon) ice but I'm afraid that with the fish stressed in the cold water already, I could accidentally cause my own fish kill. If all this is right, what is a good "start-up schedule" for aerating and when is the best time/temperature to start?

Double-Camp, here is a recent thread on winter aeration, when using to melt ice you will want to have your diffusor located in shallow water so you don't super cool the entire water column, it's hard on your fish.

http://www.pondboss.com/ubb/ultimatebb.php?ubb=get_topic;f=12;t=000090;p=1

Shorty: Thanks! I read: "Maintaining open water all winter in a small pond will have more negative factors than positive." I think that answers my main question. Also, I believe the posts led me towards starting my aerator when the water reaches 45* ~ 50*. For southern Oregon, this is VERY unusual to have ice/snow completely covering the pond, so I am staying alert with being safe, rather than sorry. The blessing is, the Merganzers can't get to my BG now! :p

DCamp - To clarify your comment of - ..."when first starting up in the Spring, as the aerating will bring up too much bad water all at once and harm the fish. Is this right?"

Starting aeration in early spring or even mid-spring will very rarely ever harm the fish. Harming fish from initial aeration startup will only occur if the pond is thermally stratified and the deep water layer is devoid of oxygen (anoxic). Normally ponds have ample dissolved oxygen in the deep zone until late spring or early summer. Bringing up large amounts of water containing no oxygen and varying amounts of hydrogen sulfide (H2S) are what becomes harmful to fish due to the resultant water quality deterioration of the upper layer waters from the mechanical inversion of the pond. From this situation, one can conclude that the apparent extensive bubbling action from the diffuser adds very little dissolved oxygen to the rising column of water. If the diffuser was adding lots of DO to the upwelling water, then there would be little chance of harming fish due to oxygen shortages from aerating.

Bill, I concluded based on some simple calculations several years ago that just as you say an aerator does not add much oxygen to the water. I simply calculated the surface area of the bubbles from an aerator and compared that to the surface area of the pond and the change over of surface water caused by the volume being circulated by the aerator. If you assume some reasonable rate of oxygen transfer from the air in the bubbles and the air on the surface of the pond you find that the oxygen transfer that occurs within the aerator bubbles is a very small fraction of what occurs on the pond surface even if you assume no surface water movement. We're talking orders of magnitude more oxygen transfer if you look at the surface water being exchanged by the aerator. I don't remember the exact numbers but those calculations told me that you don't get oxygen from the air you pump. The valuable thing is water movement. Which is why you need the aerator with the smallest bubbles and the largest flow you can get through it. I think these conclusions agree with the experience of those more expert than I, am I correct?

Interesting Point, about the aerator not putting as much DO into the water as we think. Though I totally agree on that point, I like to think that I am doing more good with the aerator by 'moving' the water around than actually aerating it. I think I just read in this month's PB something along those lines. So, IS there a good water temperature to wait for before starting aerating in the Spring? My apparent anxiousness comes from the fact that I have too many (fat, fed) BG, along with an increasing population of LMB and CC growing in there, all making little fish doodies... :rolleyes: I believe that by keeping the water moving for as many months as I can, generally, improves the over-all water quality. 4 years, and so far, so good.

bz - you are absolutely correct!
D-C - can you clear away some of the snow so that the light can get through the ice?

D-C, I can tell you that I start my aerator in one section of my pond (I have two sections separated by a long channel) in mid March when the ice is still 2 feet thick but I make sure the daytime temps are over 40 degrees so the air doesn't cool the water. I do start it gradually by doing short run times before going longer. First I drill a hole right over the aerator. Then I turn the aerator on. I lean down over the hole as close as I can get down wind and smell the air coming up. If there is hydrogen sulfide (rotten egg) smell coming out of the hole then I don't run it very long that first time (20 minutes). Then I try this every day after that and I let it run longer each day. As soon as I smell no more rotten egg then I let her rip. I've never killed any fish by doing this.

Sue: Here in southern Origun, generally speaking, ice, much less snow ON the ice on the pond, is RARELY a problem, except this year. So, the snow is already off the ice, and maybe in 3 days the ice will be melted also. This is the first in 5 years that the pond has froze over. DZ: Daytime temps of 40 will be happening next month, and I plan on doing exactly what you recomended; 20 mins on start-up, and smell the water coming up. Over-all, it's naturally a very healthy pond, though I have been aerating from early Spring to late fall. As I have stated, I like getting the water moving as soon and as much as I can. That seems to be part of my uneducated success. :p

bz - your aeration start-up proceedure is a very good technique. The main difference between you and many of the other readers is they do not have real thick ice to deal with at end of winter or or early spring. The nose test for hydrogen sulfide will indicate that the aeration start-up will need to be a gradual proceedure and compressor run times increased each succeeding day.