Pond Boss Forums GENERAL QUESTIONS Help Gases at the bottom of my lake

Hey guys. New to here but will probably become a permanent fixture. What an awesome place to go! First of all, I have a 6-7 acre lake in central wisconsin and when I bought it, I put 500 LMB and 2,500 BG in there and they went from 4-6" and 3-5" respectively from spring to 12-13" and 6-8" by fall. I had a Vertec aerator put in right before freeze-up but because they turned it on full-time right away (and right prior to the lake freezing up that probably attributed to the problem), they caused a complete fish-kill that I just recently was able to corroborate. Last spring, I ended up taking a couple full-day trips to the other part of the state to acquire fish as I rent cottages on this private lake and owed it to my clients for them to be able to catch fish. Just prior to verifying what had caused my fish to die, you can imagine I was very concerned with my fish this winter!! Any ways, they are doing excellent!! I have LMB, BG, BC and YP.
My question is, I have a back-hoe guy that I want to come out and clean out a couple shallow areas (and dig them deeper) on the upside of the lake (it is shaped like a hotdog-long and narrower) and would like him to take advantage of the ground being frozen but am concerned that he may dig up a lot of gases or toxics and with the ice covering, may pose a threat again to the fish.
Any recommendations?

Hey Brian, welcome to Pond Boss. Bump to the top for ya.

Experts?

Now just who do you think has more expertise on hot air than yourself, JHAP?

OH SNAP!

Yolk you're quickly moving to the top of my "Terminate With Extreme Prejudice" list.

I don't think you will have any problems as any gases that are exposed, if any, should just off-gas into the air.

I've done this same backhoe type thing in my pond to create some deep holes and it's worked fine.

Be sure you have a way to vent thru the ice for a day or two minimum if you have had problems before.If your concern is the area refreezing too fast before the hydrongen sulfide has a chance to gass off your concern may be valid. Not sure if the rapid startup on your aeration system was a problem due to pumping low DO water to the surface or putting gasses in the water column too fast or both. I would be intereseted in the particulars on that if you dont mind.If thin ice is not a problem and you have one of your diffusers in the general area you can turn one or two of those on if your air temps are not extremely low.

Well, that is what I'm concerned about. When we first started the aerator system a year ago last fall, it killed all my fish (and probably all the minnows that were already abundant). This was because it was not run properly when first began. It brought the gases up from the bottom and killed everything.

My assumption was that in the shallow areas, you'd be OK plus the backhoe would break up any ice for long enough to off-gas.

But make no mistake, Ted knows his gas.

Ted,
I am not sure which was the main culprit. I just know that they did start the aerator up 100% right away and the owner's manual stated not to because it would cause a fish-kill. The fish up to that time had grown very well through the summer and right up to the time the aerator was initiated. Same circumstances as this year but the ice-fishing has continued to be very good.

Just curious, either way it was a huge mistake. Often on day 5 or 6 on startup which is the 4-8 hours runtime you really need to watch fish reaction and smell your water. Older nutrient laiden and deep ponds may need to be held at the 4 hour or 8 hour runtime for many days in a row.The suggested startup procedue is just a rough guideline and every pond or lake can react differently.The only time you would go 24/7 to start is in a new pond with no fish that you wanted to pump up prior to stocking, especially if you were starting out with high numbers of mature fish. If your system isnt running year round (with LMB in your area you may not want to) be aware that if your lake is "mature" that you should exercise a start up procedure each spring.The total number of "turns" that your lake was sized for will have an effect on all of this also.This is why proper sizing is so important.

Ted,
My plan (and recommendation) is to run the shallow and medium area year-round and the deep area just in spring, summer and fall.
Does that sound o.k. to you?

Do you have a single compressor system and standard airstations, which model do you have and do you know how many turns it was sized for, if not I can calculate with some minor additional info.

It is a vertec unit with three sets of four diffusers (one in the shallow, one in the middle and one in the deep end). It was assessed by Vertec for my size and shape of lake. Not sure if it is a 1/2, 2/3/ 1 hp compressor. Does that help?
Thanks Ted.
btw- i have 3 hoses coming out of the compressor box, one to each diffuser.