Pond Boss Forums AERATION Systems questions Pond Rehab in Colorado

Hello all - great forum, and I'm glad I found you guys!

We recently moved into a townhouse in Colorado, backing up to a 0.6 acre pond. We moved in the spring, before the big bloom, and have noticed that nobody from the HOA was really doing appropriate pond maintenance. It was so bad that we lost two large carp in the pond, which I would estimate at 24-30", seemingly very big for such shallow water. I unfortunately haven't seen any other fish since then. Thus, I joined the board, and am tackling the project.

First step was to try to and get a handle on reeds/cattails. I threw on the waders and cleared probably 500+ square feet in the first couple days. Will likely need to get another 1000 square feet cleared out in the spring after the red-winged blackbirds are done nesting. (Who needs a gym membership...)

What I could use help on are the next steps. The pond is unfortunately shallow, maybe 5 feet at the deepest point, with much of it in the 3 foot range. There is quite a bit of muck on the bottom, and very little water movement. The HOA tells me they've been paying for microbe treatment, but I'm not convinced the contractor has been particularly diligent in doing all the treatments (I work from home, and haven't seen anyone come by)

First step would seem to be adding aeration. We're not interested in a fountain, and have focused on the Vertex system which seems very well put together. Due to the shallow water, I assume we would need multiple stations, perhaps 3 or 4? Regarding system size, can we get away with a Vertex 1 system with some add-on aeration stations? If this would work, would the cabinet from this system have enough room for plumbing additional hoses? Alternatively, would linear aeration tubes be better for this application?

Second step seems to be microbe treatment to catch up with the muck, algae, and duckweed. The maintenance contractor had signed up to apply 'Waste and Sludge Reducer', though I'm wondering if that's the best product for our application. Does anyone have thoughts on 'NT-Max Pond & Lake Treatment' or other treatments?

I see these solutions as delaying an inevitable dredging, which we might do in 3-4 years after we've built up reserves. Knowing that, is there anything else you kind folks would recommend?

Thanks very much for your help!

Welcome to PB. Aeration would help in several respects. I suggest you send a PM to Sue Cruz with Vertex. She can answer your questions and size/design the system for your pond. Be sure to ask about shallow water diffusers. See this link http://www.pondboss.com/forums/ubbthreads.php?ubb=showprofile&User=1637

The effectiveness of microbe/bacteria treatments to reduce muck is uncertain with many here.

Frontranger,

IMO, aeration tubing is the only way to go in shallow water...if you can. I like it for shallow water because circulation with air diffusion decreases as depth decreases. So lets say hypothetically a single diffuser can aerate a 1 acre pond that is 15' deep. That same diffuser isn't likely to be nearly as effective in a 1 acre pond that is only 4' deep. With aeration tubing you can distribute the aeration over a larger surface area with the same amount of air. The caveate is that in order to use the tubing, your depth must be fairly constant as differences in depth will create pressure differences along the tubing which will cause some areas to bubble more aggresively while others might not bubble at all.

While there is some contention on the effectiveness of bacteria applications, if you do subscribe to that treatment, it's important to maintain high DO levels since the bacteria that is used is almost exclusively aerobic. There are several other factors to consider as well when embarking on a bacteria program. I believe that these factors are often overlooked which results in poor performance and therefore contributes to the negative perception of using supplemental bacteria for water treatment. In short, (sorry, too late) not every pond is a good candidate for bacteria.

Thanks very much for the replies - I sincerely appreciate your help, and the wealth of knowledge on this forum.

I'll post photos in the spring as we move forward with the remediation!

WaterWizard, I agree with the idea of that single diffuser at a 15 ft depth you mention as an example but with that same volume of air you would use perhaps 3 or 4 airstations instead for a shallow situation.It usually takes more equipment to aerate shallow then it does deep.Also single diffusers should be a thing of the past ( I realize you were making a valid point)Research and testing has given us many different disc configuations for different circumstances. The same discs may be configured many different ways and placed differently depending on what needs to be accomplished.We have had a specific Shallow water model from Vertex since 2007. This is why Im sure you stress "proper sizing" as much as we do.I think your bacteria comments are dead on and I appreciate your comments past and future.

Thanks Ted,

Yes proper sizing is huge. We've walked away from several projects because the owner didn't want to take on the expense of doing it right. I'm sure you've run into this situation.

Anyways, I didn't mean to say that using several stations wouldn't work because it absolutely will. We just prefer to use linear aeration in shallow water applications if possible. It distributes the air well and reduces the amount of feeder tubing required compared to going to several stations. But, it's not without its drawbacks. Honestly, most ponds have too much bottom contour to use it.

I checked out your website which is very nice by the way. Anyways, I was wondering if you could explain the difference between the shallow water version and the other standard models. Are the membranes different, different sized heads, different bubble size, less slits? How can you increase the number of diffuser heads without increasing the total system airflow?

We did some R&D last winter, measuring the upward flow of water above our AirStations at different depths and configurations/spacing of the discs. We found that when the discs are too spread out that the bubble columns actually work against each other by coming up as two seperate columns and fighting each other at the "seam" on the surface. Ideally you want the seperate bubble columns to come together under water and work together to maximize the lifting capability of the AirStation. We found that our standard 2 disc AirStation had to be in pretty deep water to avoid the "seam", so we shortened the arms that seperate the 2 discs and brought them in close enough so that they are more efficient in water below 8'. We also found that by adding a 5th center disc to our XL (4 disc) AirStation, we could stablize the bubble column and avoid a "cross seam" and there for make a much more efficient AirStation for shallow and deep water. Obviously the more discs you have the more air you need, but they don't require very much air (as little as 0.5 CFM per disc).

The assumption of the air supply to a single disk mentioned was that it would probably have more than 3 cfm.There seems to be many single diffuser discs on the market that require a great deal of air supply which usually is not a problem for the waste water industry with their large regenative blowers. Mostpond and lake compressors today that are above 1.5 cfm are either 4.2 >4.4 > 5.2 or 5.6 or greater cfm when you start using the larger hp rotary vanes. With a 4.2 or 4.4 cfm compressor it would be logical to size 3 AirStations (6 total discs) if the total tubing runs and the water depth did not lower the available cfm's below the operating range. The operating range however is from .5 to 1.25 cfm per disc (Vertex)Cfm's over this can stretch out the membranes and produce larger bubbles than intended(larger bubbles lift less water)You brought up a great point on varying depths as Vertex discs include "FlowControl" technology which equalizes airflow to all diffusers (discs) on the same weight base on uneven bottoms.Sue thanks for chiming in.

So basically the shallow water version has its diffuser heads closer together so that the two columns entrain sooner, and you use more stations with less air to each station so long as you stay within the air specs of the membranes. Did I get that right?

In a shallow water situation compared to using a single disc (not a Vertex option)that would be correct. Placement of the AirStations now gets to be more critical in order to effect all of the water.Deeper water is more forgiving but we work with a lot of shallow retention type ponds.When you mention the lack of bubbles in the dips in linear tubing could one increase the air volume to increase the pressure to over ride that to some degree with out any negative effect ?I can see it at a minimum pressure but what about midrange of a maximum cfm (pressure) range?

I think that more air could be added but we tend to try to stick to the optimum cfm per foot of tubing. Feeding air to the tubing from both ends helps and we never run more than 125' while feeding it from only one end. It's just asking for trouble. Basically the tubing requires 1.5 - 2 lbs of back pressure to open the slits in the tubing. Theoretically this means that there could be 4 feet of depth difference along a single line of tubing and still get a consistent bubble pattern. For all practical purposes the depth difference can only be about 2 feet. That's why I say that very few ponds can use linear aeration. Here is a nice image that shows the bubble action from 100' of tubing in 6 feet of water.



Oops, came out kind of small but you can see the stuff bubbles like crazy.

Nice! Your photo shows it even better. How deep is it? Is this the same pond with the island?

Yes Rich, it's the same pond, the 50 ft. of bubble hose is in 4 to 5 ft. of water and powered by a small 1/8 hp linear pump.