Pond Boss Forums AERATION Systems questions help tweaking current aeration system

Hey guys ... I built this system a few years ago but after re reading a bunch of the forums I think I could tweet my system a bit .. my pond is 1 surface acres.. I would say .75 acre of that is the main pool and is 12 ft deep the other .15 is a tapering cover and the last .10 is a sandbar point ... I calculated roughly 3,296,619 gal and shooting for turning over 2X a day or 7,235,233 gal.
right now I have a cast 0523.. I have 1/2 pex going 275' to a manifold by pond.. I have 100' of 5/8 weighted line going to 2 vertex 9 discs
( I also have a shallow 3' deep vertex I switch to at the manifold in the winter that's 20' of 3/4 pex under water)

im coming up with about 8# psi I should have that being for the depth and the two diffusers.. but my gauge at pump is reading 12# of back pressure and I think its creating the pump to get hotter than it should.. I think these gases are rated to 10 psi.

problems
1. I think I need to change the 1/2 pex from pump to manifold to hopefully drop back pressure a few pounds.
2. I think with my setup and the size shape of pond I should run another 9" vertex off manifold towards the other end of the pond since the main double is off center of the main pool right now and away from the shallower cove..

it gets super hot here in the summer in western Illinois and I plan on turning over 2x per day so in the summer I can have my home automation turn the thing off when outside temps get over a certain temp or just at night... is this a good idea if so what would be ideal outside air temp to turn off at..

I have HSB stocked and this pond is low with little airflow I have sonar holding duckweed at bay but hope to correct pond with aeration and bacteria...

Is there anything else you could see could use improvement or other ideas or critiques?
Thanks everyone!
[img]https://ibb.co/p2fJwZ3[/img]
[img]https://ibb.co/znnvqgY[/img]

pond is low meaning low elevation not much wind....*

Yes - I think the 1/2" pex to the pond is too small ID. It should at least be 5/8" and better 3/4" for 275ft. To check your pex back pressure disconnect the pex from airline/s at the pond. Turn on the pump and read the pressure of pump pushing air just through the manifold and pex. This reading gives you the back pressure before the air goes to the weighted tubing to the diffusers.
Also Vertex diffusers by themselves have a self leveling air flow built into them thus this creates some additional back pressure on the pump which could be most of your excess pressure problem?? This was discussed here on the Forum a couple years ago. I forget how much the back pressure amounted to. You can test it yourself. Take the diffusers out of the water. With a short hose in the shop hook one or both directly to the compressor. Read the pressure - this is the inherent back pressure for your Vertex diffusers. If you do this report your results back here to educate others.

To get your pump to run a little cooler, run it at night. GAST rotary vanes will run hot by design with a normal run temp of 205F and water boils at 212. They have an auto -thermal shut down at 256F.

Bill has shot you some great info (as Bill usually does!)

Regarding your 1/2 pex going 275' to a manifold by pond...

Some crude calculations using the following Online Compressed Air Pipeline Pressure Drop Calculator...

https://www.engineeringtoolbox.com/pressure-drop-compressed-air-pipes-d_852.html


Using 4 CFM air flow (a decent estimate), 275 feet of line, and 10 psi, We get the following pressure losses for the noted line sizes...

1/2" ID PEX will steal close to 7psi from your pump,

5/8" takes over 2 psi,

3/4" wants less than one, and

1" requires less than 1/4 psi.

Keep in mind that once the line size is increased, the pressure drops and the air flow changes (increases), but the above numbers used in the calculator won't chane enough to ruin the example, just alter the results slightly.

So, you can see that jumping to 5/8" ID line should reduce your pump pressure by about 5 psi (leaving you pump runing at 7psi - still a little high for my liking) and going to the bigger 3/4" would leave your pump running around 6psi (not bad, but could be better). Going with 1" could reduce your pump back pressure to just over 5psi. The 3/4 to 1" jump may not buy you enough to warrant the added cost so those two are your choices. 3/4" will work well with 3 or 4 diffusers, but one inch would allow for future upgrades should you chose to push more air (bigger pump) through more than 4 diffusers.

The above mumbo jumbo relies alot on the remaining system's design dimensions. Your manifold pieces should, ideally, have internal dimensions the are 5/8" inner diameter (or close to that ID -1/2 would be OK). If you have fittings or valves at the pond that restrict the air flow much beyond the hose ID, you will see a back pressure increase from that restriction. You are already pushing air through a 5/8" hose...why try to cram it through a fitting with a lesser internal diameter.

Let's assume that you get the 3/4" feed line and your pump's backpressure lands at 5psi. The 0523 pump curves states that your pump will be pushing a little over 4 CFM. That's good for 3 or 4 diffusers.

If the diffusers are set at the bottom (therabouts 12')...those 2 diffusers should be moving in excess of 5,600,000 gallons a day (kep in mind they are overdriven with 2 CFM per head, so the lift calc is low). Not quite the 2X you are looking for, but very close if not over due to being overdriven. Adding a 3rd diffuser at the bottom would push more than 8,400,000 gallons a day if run 24 hours in that day. You would need to run this system for about 9.5 hours in a day to get one full turnover. Not Bad! The previous set of numbers is hard to estimate because the lift charts for vertex diffusers do not specify varying CFM's. Your 2 diffuser system would be overrunning the heads by about 2X, hence produce more water lift (theoretically). I assume the charts are based on their 1 CFM per diffuser recomendation. Adding a 4th diffuser reduces the amount of air that each diffuser sees which puts the CFM at the charts reccomended flow. 4 diffusers allows a more spread out placement in areas that you may want more aeration/surface agitation... 4 diffusers could produce 11,200,000 gallons per day. That's over 3X

Since I am spending your money...go with 4 diffusers with their own dedicated 5/8" lines from the manifold and the 3/4" or 1" feedline. Put two diffusers spread out in the deep area, one where it looks good in medium to deep water, and the last in a shallow for wintertime. I'd put control valves on each leg to ballace the flows as desired (run the shallow one in the summer with it choked back to flow like the others, otherwise it will boil like mad and the others will suffer). If you only run a single diffuser in the winter...you'll want to dump some air at the pump to avoid blowing up your single diffuser. I don't know if that is really a concern, but when vertex says the diffuser is rated at 1 CFM, 4 CFM sure seems like alot. An additional flow control dump valve would allow for the excess air to be dumped to the atmoshere.

EDIT: do the feild tests that Bill mentioned and compare to our calcs and post back some results. I like to be double checked.

Wow is all I can say.. these were amazing answers to my question ... I know exactly what to do now... I actually have 275’ of 1.25id black poly water line I could use that’s been sitting around here for quite some time ... any harm in using 1.25”?!? I will do all this ... and I will report back the answers .. man I still can’t get over how awesome these answers were! is turning over 3 times ok at what point is there to much aeration? Also I have a switch for the pump that I can control with my home automation.. so if you had your choice of what triggered the pump to go on and off in the heat of summer would it just be night time on daytime off or would you trigger it on and off based off of air temperature?Thanks guys!!

I'd use the 1.25" if I had it laying around without a doubt. The only downside I can think of is the small added cost of the larger fittings that would be required to plumb it down at the manifold and pump, but that should not be a big deal.

I am still trying to figure out the best number of turnovers for my small pond as I fight muddy waters. I continue to beIeive that "more aeration is better", but I struggle finding the ballance beteween stirring up the water and maximizing the aeration. I have the 0523 pump and 3 vertex diffusers in my 1/4 acre / 10 foot deep pond which, if all diffusers are set up on the bottom of the pond, can turn it over many many times in a day (7 or 8 IIRC). I have elevated my two deepest diffusers to be about 6 -7 feet from the surface and have a more shallow one at a bout 4 feet from the surface (all 3 feet above the pond floor). This elevated status of the diffusers reduces the turnovers per day and reduces the amount of muddy waters. The system is much bigger than I need, but raising the diffusers off the bottom helps lower the water flow velocities and still conditions the surface. Surface conditioning is a plus, albeit minor, at my small windless pond as it tends to get surface floaties alot. My pond also gets more water throughput because it has an abumdant watershed.

I have considered going to the "set it and forget it" route and just set the thing to run about 6 hours a night starting about now. This gives the pond about 2 turnovers and allows the muddy waters to settle all day long before I typically frequent the pond and want to enjoy clearer waters.

For the last two years, I have watched the air versus water temps. In the spring, I run the air during the warmer hours of the day and as summer comes on, I start to move the runtimes towards the cooler hours of the night. Then back the other direction getting into fall. This, in my rattled mind, helps warm the waters earlier in the year, helps keep it cooler in the heat of the summer, and aids in keeping the water warmer as the year fades. Is it worth the hassle? IDK...it's just what I have done. If I move the runtimes too abrublty, it seems to affect the feeding habits of the fish, but my fish are weak feeders to begin with. I watch the water temps at 18" down from the surface and compare that to the daytime air highs/lows and make adjustments from there. I am seriously considering just going to nightime air very soon for the reasons above.

One thing that I have done to determine the time it takes to turn the pond over is watch the water temps top to bottom. Before the air is turned on in the spring...the water will be warmer at the upper 18" and cooler at the bottom. Gradually bring the air up starting with 15 minutes and doubling every day checking the very bottom temp and 18" temp before and after the runtime. Once you get to the point where the water temp is within a few degerees top 18" to very bottom...your have found your approximate turnover rate. The key word is "approximate" as I am making this up as I go. I will continue to increase the runtime until I have, at least, doubled the "approximate" turnover time just to be safe. IIRC my pond hits consistant temps at the 3-4 hour mark and I am currently running from 9am to 4pm. My pond is looking pretty muddy with all the rains we've had and reducing the runtime and moving it to nights is really tempting...maybe in a week or so...it's going to be cold at nights this week.

With all that said...if I was not fighting murky water, I would run the air as much as I could so long as it did not encourage the 18" water depth to get warmer than the low to mid 80's in the heat of the summer.

all such great info... So im getting ready to build a system for my other pond( this is what got me reading the forums again) rather than make another post in the forum on that ill just put what I got here in this thread to see if you guys think im on target with its design..

This one is 2.2 acre or 7,235,233 gallons.. 12-13 ft deep in main pool... Shooting for roughly 2x turnover would be 14,4770466 gallons or 5-6 vertex 9" discs.. This would put me using a gast 0823 3/4hp pump.

Ive attached an aerial of the pond and my thoughts for diffuser locations.. Basically the main pool is 12-13 ft deep fairly flat edge to edge.. The two coves on the west side gradually get shallower.

my thoughts are
- two double diffuser plates in the main pool at 12' deep spaced evenly (would move 10,368,000 gallons per day)
-one diffuser in each cove on the west side at around 10' (would move 4320000 gallons per day)
-one diffuser in 4' for winter (lift 864,000 gallons a day)

total lift per day would be 15552000 or 2.14 turnover times

I would run Gast 0823- 1.25id hose -to individual ball valves running each diffuser-5/8 weighted line- diffusers..

I think I learned enough to have this part close..What are you thoughts?

my main question is do have a good game plan going for the placement of the diffusers in the pond? do the ones in the coves need to go farther into the coves?

This pond has been neglected... it sits down in the timber with not much wind. there is a duckweed problem which im getting ready to treat with fluridone... I've had fish kills and I think it has to do with nutrient load lots of muck leaves and the duckweed every year.. my goal with the pond is to treat duckweed get aeration and bacteria going to start solving nutrient prob then when things look good stock it to start trying to make it a trophy bass pond.. This pond is one cool pond it has standing timber and stumps everywhere.. wood duck and largemouth heaven!

( in the photo attached the white pin would be pump location. yellow pin would be shallow diffuser. blue pins would be the deep doubles.. and the reds would be the single diffusers in about 10'
Thanks again guys
https://ibb.co/7gJ57xZ

It all looks great to me. The only things that I can add are...

1.) To use something better than ball valves to contol flow. They will work, but will not give much fine tuning and will be hard to set "just right". Gate valves are a much better chioce on the affordable side and actual flow control valves are much better, but get pricey.

2.) Use a dump valve (I used a flow control valve - a gate valve would be OK here too) so that when you are using the wintertime head, you are not pumping the whole load to that one diffuser or choking the pump. If you turn off all the deep diffusers and leave the shallow one wide open...you will shorten the life of that head...if you choke that head down...your pump pressure will skyrocket and you'll shorten the life of the pump. I open the dump valve all the way exhausting the pumps air out to atmosphere, turn off my deep heads, leave the shallow one wide open, and then start shutting the dump valve until I get it to look right. Most of your air is just escaping and you are only getting enough to the one shallow diffuser to make it work at a proper level. The most efficient way to do this is to swap out pumps in the wintertime to one that is sized for just one head, but not necessary if you are OK wasting some energy.

3.) Install a pressure relief valve at the pump just in case something gets plugged up. You don't want your pump pushing against a blocked line and overheating. I bought one from McMaster Carr. It is adjustable from zero tp 20 psi. It always leaks a small amount, but is good insurance. IIRC I set it at 10psi - thereabouts...

48935K25 - Adjustable Pressure- and Vacuum-Relief Valves for Air and Inert Gas, 440C Stainless Steel Seal, 1/4 NPT Male


While I am here, I will throw out what I bought for the pump house cooling fan, intake filter, and gage...


4369K31 Corrosion-Resistant Air-Intake Filter, 1/4 NPT Male, 10 scfm @ 100 PSI Maximum Flow Rate, (note: comes with filter element)

4369K38 2-1/4" High Paper Element for Corrosion-Resistant Air-Intake Filter

9191K32 Equipment-Cooling Fan Kit with Thermostat, 4.69" Square, 100 CFM Airflow, Steel Guard

3845K1 Vibration-Resistant Pressure Gauge with Plastic Case, Dual Scale, 1/4 NPT Male Bottom Connection, 0-30 PSI

Hope this helps!

Awesome what do you use for a housing for your pump and do you have pictures of that housing and the fan set up?

There are better planned pump boxes that other members have put together. Hopefully they will post some pics for you, but here's my pump out- house...



The exhaust for the fan is the little rectangular screened opening at the top front. The fan is inside that opening blowing outward sucking air across the pump. I don't think it makes much difference if the fan is pushing air out or pulling it in from a cooling point of view, but I did not want to suck rain water in so I mounted it blowing out.

Here is the inside...



There is a long screened slot under the pump shelf that allows the air to be drawn in and across the motor. The pump is behind the white panel directly behind the drop light and the pump house has a false ceiling it that the fan lives in. So, it pulls air from the open area inside the house up through the enclosed pump shelf cabinet and through the false ceiling and out the top front. Rule of thumb...make the opening in the box opposite the fan twice the size of the fan cross sectional area. This applies wether you are pushing or pulling the air.

The only thing missing in the plumbing is the dump valve that I added by the pop-off valve.

The Vertex diffusers need 1/2 psi to open. They have a backflow valve built into them.

We typically use 1" poly line when running to a manifold box, but do the calcs if running a long distance to see if it needs to be upsized. We used 2" at one pond because the electric was 1/2 mile from the pond.......

Vertex uses ball valves in all their manifolds and I've never had a problem balancing out the flow to each diffuser.

Good idea on using a dump valve to bleed off excess pressure for the winter. I have a remote manifold box at my pond and have an extra ball valve in it to do just that for the winter.

As usual QA is on point. All I would add is this. You could always swap out your winter aeration disc to one that flows more CFM to make courser bubbles. Then you could send all the air through the pond instead of bleeding excess off.

Man such awesome answers .. so it looks like a lot of people set the dump valve to where that winter boil “looks right” ... but you essentially want your pressure gauge to read what your summertime reading is at full capacity with all diffusers running?!( if you are running a number of diffusers at pumps Max capacity of cfms ) this would be same as saying you want psi to be back pressure from lines + backpressure from
Depth plus 1 lb roughy for the single winter diffuser ... or like last comment stated swap our for a cfm rated diffuser = to all summer diffusers combined..
I think I’m starting to understand this math equation 😂
Thanks again everyone!

What is the correct way to set the pressure relief valve? I put on my pump that’s running at 13psi ( haven’t changed pipe size yet) and no matter how far I back out the relief valve it does regulate the pressure down?

IIRC, My releif valve would be set at the highest pressure if it was screwed in all the way in and the relief setpoint was lessened by unscrewing the adjustment head. With the pump running and the diffusers bubbling, seeing about 5 psi on my system and the relief valve turned all the way in...I stared to choke the air off to the diffusers until I got a steady 10 psi reading, then I started to loosen the releif valve until it popped off. At that point, I opened the air control valves to the diffusers until the releif valve closed back up (I might of had to turn the pump off to get the relief valve to reset I don't recall). Then I started to choke the diffusers again and as the presure went up, I watched the gage and listened for the relief valve to open. I had to do this a few times to get the relief valve set at the 10 psi mark as it is not the most precise valve out there, but once I got the releif valve to pop open at 10psi on the gage...I was done (after I opend the flow back up to the diffusers, of course).

Some of these relef valves also work for vacuum and the postion of the ball and spring inside have to be reversed to work in the opposite direction. Mine needed the ball to go in first...then the spring. My style of releif valve is not a pressure regulator, but just a "pop-off" at the set pressure.

So part of my problems was that I had a faulty pressure gauge... got that swapped ...so when I cut the 1/2 “ line off at the pond manifold went back up the line pressure loss was 5.5lbs ... I’m sure your calculations were off by about the distance my guess was off of the run! Swapped line for 1.25” line and measured no line pressure! I’m now running the two deep 12’ diffusers on one 5/8 line and a shallow water 3’ diffuser and measuring 6.5#... I wasn’t able to bring diffusers in to shop to test backpressure there .. I’m going to
Add the 4th diffuser when fitting comes in and I’ll take actual depth measurements when I’m out there... thanks