For many years I was under the impression a bottom diffuser "aeration" system added oxygen to the water until my second fish kill using a "state-of-art" bottom diffuser system.

Todd Overton recommended a surface aerator which I now use in conjunction with a bottom diffuser circulator.

With due respect to vendors, I wish the terminology would be better defined or clarified.
I believe I could have avoided a major fish kill - my fault!
George

what type of surface aeration are you using?

1 HP Kasco...

http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Main=23883&Number=300093#Post300093

George,

I got this right out of the pond archives. It's Bruce talking about air diffusers.


"When you put a diffuser on the bottom of your pond and bubbles start to come out of it, the fish really aren't interested in gulping the bubbles. What they really want is the pure oxygen that's diffusing out of the bubble across the "air/water interface".

In high school physics class we learned that lots of smaller bubbles have a lot greater surface area than a few big bubbles. That's why a good diffuser makes the bubbles as tiny as possible. Lots more little bubbles means more surface area, which means more "air/water interface", which means more oxygen diffused into the water for the fishies to use.

Make sure to get a good diffuser. This helps. But what a bottom diffuser aerator system really does is brings a big column of water up from the bottom so that the unoxygenated bottom water gets a chance to gulp some oxygen from the gigantic "air/water interface" at the surface of the pond. This produces a lot more usable oxygen than the bubbles themselves."

Yes that's correct, but main effect is circulation to avoid stratification, which does increase O2 but not enough to avoid a major fish kill in hot Texas low water conditions.

So what your saying is you had a air station going 24/7 and you still had a major fish kill due to lack of D.O.?

How big was this pond? Was it overstocked you think? Are you 100 percent sure it was a D.O. issue?

Just asking as I don't want the same thing to happen to me!

RC

RC51, I had a perfect balanced 2 acre pond that the drought reduced to one acre - for sure I had too many fish in reduced water body and not enough O2 to go around.
Yes, I had a bottom diffuser "aeration" system running 24/7- Gast rotary vane pump w/ Vertex diffusers.
Extreme conditions warrant extreme steps - some fish farmers use "paddle wheel" devises for emergencies - us regular guys get fish kills.

Fortunately our pond was deep enough to recover.
G/

Oh ok I got ya. Wow an acre low!! that's crazy! Sorry to hear that sir!

RC

So George,

Are you running that thing right along with the diffusers or are you keeping it as a "hot day aeration emergency" tool?

Always interested in your pond input.

John

John, bottom diffuser system for daytime use - surface aerator nights and cloudy days.
Surface aerator usage begins when near surface water hits 80 degrees -off in cold water and bottom diffuser on 24/7 until winter time.
G/

Thanks George,

Surface aeration is something I considered and will put back on the table for a possible later addition. Additional question, if you dont mind, do you have any idea of where your lbs of fish vs carrying capacity was before the water loss? I have a well to add water, but that has no DO in the addition and am interested in where you think it went poorly for your pond.

Thanks again,
John

John, you do remember early summer 2011 with 100-degree temps?
Lots of Texas ponds went dry – we were lucky to have enough depth for survival.

I have no idea about lbs of fish vs carrying capacity –
It is my nature to push the envelope – you live by the sword – you die by the sword!

I do know that we were not bass heavy but any trip to our pond that spring we could count on as many 8-10+ inch CNBG as we wanted to catch and a couple or so 4-6 lb HSB.
I was expecting to catch my first 2lb CNBG and 10 lb HSB in fall 2011, but we hit the record temps and drought instead!

Todd Overton said that a surface aerator would have likely saved our fish!
George

George, I agree with your assement of your problem and Todd's fix. But, it all depends on the water depth. Surface agitation/aeration works very well in low water/shallow water conditions that you describe. In deeper BOW's? Without a tube to pull water from the deeper portion of the pond, not so much for the deeper water areas. Plus pumping air is more cost effective than pumping water in regards to energy costs. If you didn't have power at your pond, you cannot run the surface agitator/aerator unless you are well versed in solar like Brian is experimenting with.

Each system has it's place, and no single system is the best for both worlds. If you really want to have your bases covered, run both - bottom diffusion systems and a surface agitator/aeration system.

Scott, you may recall that my pond manager is Todd Overton of Overton Fisheries, one of the most qualified and respected fishery biologist in this part of the country.
Your advice is misdirected but appreciated non-the less...

"If you really want to have your bases covered, run both - bottom diffusion systems and a surface agitator/aeration system."

Go back and read previous posts - I have a dual system.
You are telling me things I already know..

So are you saying surface aerators actually add air too the water? I'm not sure i understand the point of a surface aerator? I understand what bottom diffuser does but can't see much benefits in surface?

A surface aerator basically beats oxygen into the water. It is ideal for fish farms where the carrying capacity is at its max and the ponds are typically really shallow (less than 4'). They are also ideal for emergency aeration. As far as oxygen transfer, a surface aerator can't be beat ~ don't get it confused with a fountain, though ~ fountains have a pretty display, a surface aerator churns up the surface water. A surface aerator won't de-stratify a pond and get oxygen to the bottom, but it will create a safe haven for fish in stressful times.

Won't a fountain degas the water and while the water is hurtling thru the air, pick up DO and lace, at least the surface with DO?

Thanks Sue!

George,
They actually have electric motors that are classified as "Catfish Pond Motors" for paddle wheel rigs.

They are intended for very shallow ponds with high stocking densities as Sue explained.

I employ the same measures as George not only for my customers but for my own personal pond. I should be more specific and say for my customers that we push the envelope with regarding growing lots of big fish with agressive feeding and stocking programs.

I've seen a lot, experimented a lot, and that combination allows for the best overall protection- large amounts of oxygen production from the surface agitator and great homogeneity/cirulation of the entire water volume with the bottom diffused system.

Thanks Shawn - not any fun if not pushing the envelope!

Combo of both then, which makes total sense.

I agree. In a clients pond, there are 3 dual disk air stations, and a kasco running right now. Water temps were up in the low 80's, O2 was at saturation in most of the pond water, and GRBT were still alive.

Hey George, Im with you on last year. That is why I put in the well and had to restock. I was down to 1-2" feet in about a 30' pool.

I was mostly interested in whether you felt that the surface aeration was needed because of the water loss due to evaporation led to you being over capacity and the diffusers were unable to keep up or if the thought was that with the extreme temperatures we had the diffusers couldnt keep up with the DO loss even if your water level hadnt dropped as far.

Thanks again,
John