Pond Boss Forums Thread Like Summary - Aerate or Fountain... could sure use some advice.

Hello all,
My pond is about 1.25 acres, average depth 5-6 feet, trees surround it, it is not spring fed. Water is very stagnant, lots of leaves and debris collect in it, heavy layer of muck on the bottom.

I dug furniture and garbage out of it when we moved in, cleaned the shoreline, treated the water, etc and it looks so much better, but there is an oily film on the surface that won't go away. Fish activity is very low. No real vegetation growth in the water... a few cattails and such, but overall I've got it well cleared. I don't believe there is enough oxygen to sustain the fish much longer.

So my question... would a powerful water pump fountain produce enough oxygen to help, or should I go with the "bubbler" aerator system. And with either, I'd appreciate recommendations on what and how. Money is in short supply and I will be doing it myself. I've got about $600 or so to work with.

Thanks all for sharing your perspective.

Bottom aeration, bubblers, might seem counter intuitive in that the shallower the water the less effective they become and the more diffusers you will need. The deeper the diffuser the more surface area that is affected. Try to understand the bottom contour of your pond - you could try to map it but that can be hard to do or expensive to pay for if you are on a budget. I used a couple of pieces of 3/4" PVC glued together marked in one foot increments and tested the depth at random places all over the pond using a paddle boat. I can't map using that but I was able to tell that the majority of the ponds is pretty deep and the bank goes from shallow to deep pretty fast, and I only have one area of the pond that has any shallow bank to any extent. Based on that I went with bottom diffusion. If you find most of the pond is actually shallow - in the 5' - 6' range as you noted than surface aeration is probably your best bet.

As Esshup noted, it is important how close electricity is to your pond. You can aerate with the compressor a long way from the pump but the further the pump from the pond the more discharge pressure will be required, and therefore bigger and more expensive compressor you will need so sizing becomes important. People have differing opinions on if it is better to run long air lines or run long electricity - long being subjective. I chose to run electricity - I think anytime you can get water or power to somewhere you don't have it you have added value. I had to run 230' and it cost me around $/ft for rental ditcher, 10 ga 3/1 romex, and conduit. I was able to do it myself so that save a lot. It could be cheaper if you run 2/1 romex but if you are already running power using 3/1 romex gives you the option of another circuit in the future.

I am just throwing out what I did and my thought process in the event that it is helpful. There are a number of folks on here who have designed and built their own system as you propose. I am not very familiar with surface aeration since my pond called for bottom aeration. It can be a ton of work but I made the commitment a couple of years ago after buying a place with a badly neglected pond and things are now turning the corner and we are really enjoying having a pond. The folks at Pond Boss and this forum are a great resource.

What is max depth of the pond, and how far away from electricity is it?

With such a large percentage of the pond 5-6ft deep you will always have perpetual problems with weeds and algae that always grow in shallow water 5ft and less deep. Weeds and algae are rarely problems in deeper water. Plant control will always be an ongoing increasing expense due to pond aging, annual nutrient and organics accumulation and sedimentation. Tree leaves are a big contributor to more shallow water and muck accumulation For long term planning strongly consider rebuilding the pond. If money is limiting then consider rebuilding the pond deeper but smaller. A rebuilt deeper pond will be lower cost to maintain, fewer chemicalizations, less work - less maintenance, less pond stress, and more pond enjoyment. Rebuild it right and it will be an improved long term asset not a liability that rapidly continues to fill in and create more weed algae problems. Filling in and aging is a natural part of the life of a pond. The speed or rate of degradation is the big variable based on pond location and basin morphometry (basin shape).

To address your aeration concern, I think for a 1.3ac pond you should first determine the natural depth of water mixing in this pond. In a 1 ac pond with good wind exposure the water can naturally mix down to 6-8ft sometimes 9ft. Water clarity and pond overall productivity also play roles in how deep dissolved oxygen is produced in the pond. High turbidity of 12" - 16" results in DO just produced in the upper 3-4ft whereas water clarity of 3 ft to 4 ft allows plants to make DO 6 to 10ft deep. It all depends on clarity. Know your oxygen and temperature water column profiles. If your pond does not have DO on the bottom then aeration is a big benefit to bottom sediment health with oxygenated conditions. So before spending quite a bit of money on aeration know the depth of natural water mixing in the pond and how deep the DO exists during mid summer. Clear water ponds with water less than 9-10 ft often do no need to be extensively aerated. Use aeration just during low DO periods or midsummer.

I would recommend surface aeration but what type would need to come from someone else. My recommendation is entirely based on research - lots of internet study, you tube videos and talks with folks who were not equipment vendors. I sometimes comment on this forum to pass on what I have learned and save someone the hours and hours of research I put in. Sometimes I comment and have real personal experience and knowledge. This topic combines a bit of both but I haven't personally owned a surface aeration system.

Best of luck and let us know how it goes.

I'm with Bill on the renovating. If you elect not to renovate, then you might not need any aeration whatsoever because the O2 might go deep enough without aeration like he said. I did a pond consultation a little bit ago for a Homeowners Association. water clarity was 6', there was a thermocline at 7', the level of O2 that was high enough to support fish disappeared below 8' depth.

If you elect to run electricity to the pond, make sure you use large enough wire or you run the risk of burning out whatever pump/compressor you put at the pond. Remember that it's not the running amps but the starting amps that you have to watch, and also calculate the amount of current drop over that length of run. If I was running electric to the pond, I would make sure that I ran enough wire for 220 volts.

Assuming a relatively triangular, square, or round 1.25 acre pond (not something odd like a strip mine or "V" or "W" shape) with an average depth of 4.5 feet...I believe the minimum number of diffusers would be 4 single 9" heads, all equally spaced to be at the edge of the 5 foot depth areas. This should get the pond water turned over in a 24 hour period. I would feel better with 6 heads (8 if you tend to overdo things like me) because of the shallow water depths in comparisons to the overall surface acreage. I would say this would require a pump that could put out 1 CFM per diffuser. 6 CFM would be in the neighborhood of a 3/4 HP rotary vane pump should you decide to use that style of pump. Being such a shallow BOW there are other options that could work. Diaphragm pumps in particular, but I am most familiar with the rotary vane type.

I have no experience with surface aeration which may be advantageous over bottom diffused in your situation. I'll leave that to other PM members with such experience.