I am putting together plans for and aeration system and wanted to run it by everyone.

Given:

Qty x 3, 9" Vertex diffusers,
Gast 0523 Pump
Triangular Shaped 1/4 acre Pond = 423,000 gallons, 10 foot at deepest, average depth = 6 feet.
Location - West Central Mo.
Fish - HSB, HBG, RES, FHM

Turnover Calculation:

Two diffusers in separate areas at 4 foot water depths and a single diffuser in 10 foot yields 10 turnovers per 24 hour
period. I would like to use the 3 isolated diffusers to help the water surface conditions (floaty pollen, dust, etc) and achieve good turn over rates.

Advice Requested:

Is there such a thing as too much turnover? If so, I can cut the aeration periods to the night time according to the magic number of turnovers and temperature requirements.

Should I consider moving the deepest diffuser up to the 6 or 7 foot depth to try and maintain a small thermocline for heat relief OR would that be futile in such a small pond?

Any and all comments welcome, thanks in advance...

Yes, there can be too much turnover. Bob went over this in one of the PondBoss Live shows. Not sure which one it was, but had a client do too much and fish started dying during the heat of the summer. Backed off aeration and it stopped.

#2 He went over that as well. He said put at 2/3 depth to allow that small thermocline to develop.

Let me be a bit more specific. Can there be too much turn over if temperature is ignored? And, will a thermocline develop in my 10 foot deep - 1/4 acre pond with the deepest aerator set at 2/3rds the pond depth?

I watched Bob's show about this topic and this is where my questions spawned from. I read that we should shoot for at least 1 turn over a day, but I have not read that there can be too much turn over for any other reason than high temperatures. I also have a hard time believing that my design will allow for a thermocline when my turn over calculations suggest I could get as many as 10 turnovers per day...that's got to disturb the lower 3 to 4 feet of water. It's just a small hole of water.

Quarter, a thermocline will often develop "under" the level of the diffusers, so yes, you will probably develop a thermocline/toxic-water-zone in the deepest portion of your BOW. The circulation will set up a pattern, and water density due to the temperature differences will have more impact than you may realize in preventing a good mixing.

And yes, you can have "too much" turbulence, yet it's unlikely to happen in your case.

As you say, yours is a "small hole of water"....Set your system up and after a few days, take a swim and see if you feel "colder" water in the deepest areas....

The diffusers set at a 4' depth will not have near the lift capacity that the single diffuser in the 10' depth will have....I do not know the formula (if there is one) for lift, but do know more depth exponentially increases lift capacity over shallow diffusers.

Thanks Rain! Being from Missouri, you'll have to "show me" so I guess a swim in the pond will be on order to determine if a thermocline develops. Any volunteers?

I just have a hard time imagining that the upward movement of water from the diffuser would not also pull the water up from the gradual slope that extends further down into the deepest part of the pond mixing it all up. This may be an experiment to determine the proper placement of the 2/3rds diffuser to maintain a thermocline.

The "formula" that I used was developed from Vertex's lift chart for the XL1 diffuser...



If I place two XL1 diffusers in 4 foot of water and 1 at 6 foot deep, I get...2 x 700 GPM + 1,150 GPM = 2,550 gallons moved per minute. Convert to gallons per day and I get 3,672,000 gallons per day. My pond has 423,000 gallons in it (I emptied it and filled it back up with one gallon milk jugs - lol) Dividing 3,672,000 by 423,000 = 8.68 turnovers per day. I realize tat the 4 foot diffusers may very well turn water over merely in the shallows, but if I do the calculation solely using the 2/3rd diffuser,I get...3.9 turnovers per day. I'm still well in the zone.

I think I'm doing it right.

DISCLAIMER: I know nothing!

I could be mistaken, but I did't think you necessarily want to "maintain the thermocline" during the summer??? Won't that water end up anoxic and therefore useless to the fish? I thought the 2/3rds of depth was for Winter diffuser?

If it were me I would put the diffuser on the bottom and then let water temp decide duration.

I see your calculations, but I don't see a diffuser moving only 120% or so more water volume at 10' as it shows at 4' deep....as you say, we're Missouri mules, and you'd have to show me... I seriously doubt you'd ever attain a 700GPM flow at only a 4' depth...

Well, Vertex claims...

"Lifting rate data represents total water flow recorded by independent testing and real world data collected by Vertex from installed aeration systems. Lifting rate varies significantly by air flow, water depth and other factors. XL8 data extrapolated from XL5 data."

From this page...

https://www.vertexwaterfeatures.com/aeration-lifting-rates

It's all I've got to go on. The nice thing is, if I ignore the 4 foot diffusers, I am still turning plenty of water.

I have the vertex XL5 in my .25 acre pond. My pond is 1.49 acre feet or 485,518 gallons. If I did the math correctly I’m getting 1.22 turnovers per hour! My diffuser sits 1 foot off the bottom in the center. When I purchased my diffuser I sought help from vertex and an old member here (Ted from Forever Green). I was told you can’t have too much aeration and hearing that you can is news to me. I have never had any kind of fish kill and my system was run continuously during the summer only for 7 years and at night on a timer for the last two years. I think my pond was cleaner running it continuously.

ETA: Actually I’m getting more turnover than what I stated because I used your chart that gives gpm for 10’ or 12’, I used 10’ when my diffuser is actually at 11’.