pacmann117
New member
Hello hello-
Here is a project I've been working on for a week or so. It ended up being pretty interesting, so I thought I would share:
There is an old RK2 industrial skimmer at Sea Schor (where I work nowadays), and the recirculation pump on it burned out. The standard method of introducing air into these is a big energy hungry pump pumping water through a mazzeri venturi. I wanted better performance, so I chose to modify the skimmer with a needle-wheel pump. I had modded an RK2 at MCF before, but it ended up needing to be run with an air pump (and a big one) due to the massive head pressure on the pump.
View attachment 8370
Here is a view of the skimmer minus the skimmer head. Height is roughly 5' at the head/body joint.
View attachment 8371
Funny face, but I am 6' sharp, and the skimmer is on a 6" platform, just for perspective.
View attachment 8372
Diameter of the skimmer: This is a 12" ruler, and it fits inside with about 2 inches to spare. So internal diameter is ~14"
View attachment 8373
View of the inside of skimmer body. Simple counter-current design. Water is pulled into the recirc pump from the bottom and injected into the center. The aerated water is ejected into a cup and then allowed to float upwards. Definitely allows for bubbles to recombine, but not too much I can do about it. Hopefully not significant.
View attachment 8374
ORCA pump by Reeflo. 1/24 horsepower, 2" inlet, 1.5" outlet. Needle-wheel pump.
View attachment 8375
Close-up of impeller design. Again, this is a needle-wheel variety.
So the idea here is to mount the pump as high as possible on the skimmer body so that there is minimal back pressure on the intake. It turns out that the inlet pipe on the skimmer body is roughly 4.5' off the ground, and the drain line is ~ 4' off the ground. So in the case of any combination of one or both pumps failing, the water level never falls below ~4'.
Knowing this I chose to mount the pump vertically with the pump head just below the minimum water level.
View attachment 8376
Here is the pump mounted as high as possible on the skimmer body. This is done to reduce back-pressure, as to increase aspiration, or in other words, to maximize air intake without restricting flow.
Unfortunately, Reeflo/MRC will not sell the aspirating venturi with this pump, as they don't want people doing exactly this
At this point, I would like to point out the difference between a regular venturi (the hour-glass variety), and an aspirating venturi. An aspirating venturi is much simpler than a regular (pressure?) venturi. Aspirating venturis simply use the "suction" of the pump to pull in air, once flow is restricted by a reduction in intake pump diameter. In the pressure venturi, bernouli's principle dominates, and the pipe volume is tapered down to a minimum, and air is drawn in at that minimum. Since bernouli's principle states that a liquid's pressure drops as it's velocity increases. So no complicated fluid dynamics on the aspirating venturi, take a look at your venturi if you have a needlewheel skimmer, chances are it is pretty basic.
Here is the design:
View attachment 8377
2" sch 80 PVC pipe drilled and tapped with 1/2" pipe thread. Barb is where air is pulled in. Inner sleeve is 1.5" sch 80 PVC, it just so happens that these sizes fit snug with one another. This is connected directly to the pump intake. Air is pulled in and ground up into bubbles.
View attachment 8378
The outer diameter of the inner sleeve will be reduced to allow for air to pass into the pump.
View attachment 8379
Inner view. Water is coming in here, and the diameter is reduced, allowing air to be pulled in.
View attachment 8380
Inner sleeve post epic DIY diameter reduction via hacksaw. Like shaving a gyro
View attachment 8381
Look closely here. Note cavity between inner and outer sleeve. This is where air is "aspirated" into the pump. This side is screwed into the pump face. Air is pulled in through the barb and is injected into the impeller.
View attachment 8382
Finished product. Venturi is attached to pump face
View attachment 8383
view from the other side
View attachment 8384
immediately after firing it up. No air pump here.
View attachment 8385
And a day later.
There you have it! There is no other info I could find on something like this being done, so I hope this helps other people mod up their outdated skimmers! You can also check out this build on Sea Schor's Facebook page
Here is a project I've been working on for a week or so. It ended up being pretty interesting, so I thought I would share:
There is an old RK2 industrial skimmer at Sea Schor (where I work nowadays), and the recirculation pump on it burned out. The standard method of introducing air into these is a big energy hungry pump pumping water through a mazzeri venturi. I wanted better performance, so I chose to modify the skimmer with a needle-wheel pump. I had modded an RK2 at MCF before, but it ended up needing to be run with an air pump (and a big one) due to the massive head pressure on the pump.
View attachment 8370
Here is a view of the skimmer minus the skimmer head. Height is roughly 5' at the head/body joint.
View attachment 8371
Funny face, but I am 6' sharp, and the skimmer is on a 6" platform, just for perspective.
View attachment 8372
Diameter of the skimmer: This is a 12" ruler, and it fits inside with about 2 inches to spare. So internal diameter is ~14"
View attachment 8373
View of the inside of skimmer body. Simple counter-current design. Water is pulled into the recirc pump from the bottom and injected into the center. The aerated water is ejected into a cup and then allowed to float upwards. Definitely allows for bubbles to recombine, but not too much I can do about it. Hopefully not significant.
View attachment 8374
ORCA pump by Reeflo. 1/24 horsepower, 2" inlet, 1.5" outlet. Needle-wheel pump.
View attachment 8375
Close-up of impeller design. Again, this is a needle-wheel variety.
So the idea here is to mount the pump as high as possible on the skimmer body so that there is minimal back pressure on the intake. It turns out that the inlet pipe on the skimmer body is roughly 4.5' off the ground, and the drain line is ~ 4' off the ground. So in the case of any combination of one or both pumps failing, the water level never falls below ~4'.
Knowing this I chose to mount the pump vertically with the pump head just below the minimum water level.
View attachment 8376
Here is the pump mounted as high as possible on the skimmer body. This is done to reduce back-pressure, as to increase aspiration, or in other words, to maximize air intake without restricting flow.
Unfortunately, Reeflo/MRC will not sell the aspirating venturi with this pump, as they don't want people doing exactly this
At this point, I would like to point out the difference between a regular venturi (the hour-glass variety), and an aspirating venturi. An aspirating venturi is much simpler than a regular (pressure?) venturi. Aspirating venturis simply use the "suction" of the pump to pull in air, once flow is restricted by a reduction in intake pump diameter. In the pressure venturi, bernouli's principle dominates, and the pipe volume is tapered down to a minimum, and air is drawn in at that minimum. Since bernouli's principle states that a liquid's pressure drops as it's velocity increases. So no complicated fluid dynamics on the aspirating venturi, take a look at your venturi if you have a needlewheel skimmer, chances are it is pretty basic.
Here is the design:
View attachment 8377
2" sch 80 PVC pipe drilled and tapped with 1/2" pipe thread. Barb is where air is pulled in. Inner sleeve is 1.5" sch 80 PVC, it just so happens that these sizes fit snug with one another. This is connected directly to the pump intake. Air is pulled in and ground up into bubbles.
View attachment 8378
The outer diameter of the inner sleeve will be reduced to allow for air to pass into the pump.
View attachment 8379
Inner view. Water is coming in here, and the diameter is reduced, allowing air to be pulled in.
View attachment 8380
Inner sleeve post epic DIY diameter reduction via hacksaw. Like shaving a gyro
View attachment 8381
Look closely here. Note cavity between inner and outer sleeve. This is where air is "aspirated" into the pump. This side is screwed into the pump face. Air is pulled in through the barb and is injected into the impeller.
View attachment 8382
Finished product. Venturi is attached to pump face
View attachment 8383
view from the other side
View attachment 8384
immediately after firing it up. No air pump here.
View attachment 8385
And a day later.
There you have it! There is no other info I could find on something like this being done, so I hope this helps other people mod up their outdated skimmers! You can also check out this build on Sea Schor's Facebook page
