Does water height matter? Tuning for optimal protein skimmer performance. | BRStv Investigates

Does water height matter? Tuning for optimal protein skimmer performance. | BRStv Investigates

– Today on BRSTv Investigates, who hasn’t faced the
challenge of finding that protein skimmer sweet spot between tuning and operating depth? Or even some of us still can’t seem to get it just right. This week we start a journey of solving this issue for good, starting with an attempt
to answer the question, does operating depth or water height in the sump even matter? (upbeat music) Hi, I’m Randy with this
Friday’s BRSTv Investigates where we put popular reefing gear, theories and methods to the test by experimenting on our own tanks so you don’t have to experiment on yours. And in today’s experiment we test six of the most popular internal skimmers in a similar price bracket
between $150 to $250 bucks to see how they operate at
different depths from the sump, and also to see if the
manufacturer’s recommended operating sweet spots are accurate. So, much like we did for our investigative salt mix experiments, where
we started with a single cost per gallon analysis to test, which we ended up blossoming into six full BRSTv investigates episodes, we’re hoping to explore the rabbit hole of protein skimmers in a similar fashion, hopefully with each lesson
leading to the next question in order to select the right
tool for the right job, and how to optimize the
performance of that tool for our saltwater tanks even further. I feel that the first questions
that we need to answer on our path to unraveling
skimmer performance starts with some baseline
testing of what’s happening inside the skimmer body,
where there’s an interface of forced air and water being mixed together at a high velocity in order to create a mass amount of surface area from bubbles that will eventually carry waste and unwanted dissolved organic compounds out of our tank’s water and
into the skimmer collection cup. To better understand
that relationship between air and water mixture
happening inside the skimmer, we’ll test the air draw,
measured in liters per hour, for a handful of skimmers
when installed at the manufacturer’s
recommended operating depth, and then again with those
same skimmers installed at one inch below and one inch
above those recommendations in order to explore the question, does the operating water height matter when installing your
internal protein skimmer? To test today’s question, we picked out six of our most popular internal protein skimmers from
the $150 to $250 price range, which were the Reef Octopus 150INT, 110INT Classic, the Somatic 60S Space Saving Skimmer, Skimz SN127DC Skimmer, Eshopps X-120 Axium Space Saving Skimmer, and the Reef Octopus 110SSS
Space Saving Skimmer. Using the recommended
operating depth sweet spot, right in the middle of each
skimmer’s operating range, we tested the air draw for each one using this really cool
digital airflow meter we picked up from Kelly Pneumatics, which comes with 3/8
inch ports that matches some of the most common sizes
of skimmer air intake tubing. Using those air draw
numbers as a baseline, we tested what happens when
we allowed the sump level to fall outside of those optimal ranges by dropping the water to an inch below each skimmer’s recommended
operating range, then testing the airflow, followed by raising
the tank water level to an inch above the recommended level for another test of airflow. Starting with the air draw
baseline for each skimmer, measured in liters per hour, we have the Reef Octopus 150INT, which uses an 18 watt Aquatrance 2000 pump at a recommended operating
range of 7.9 to 8.7 inches which is a sweet spot of
only around 3/4 of an inch. Right in the middle of that range at about eight and a half inches of water we tested an airflow average
of 409.97 liters per hour, which ended up significantly
under the manufacturer rating of 720 liters per hour. The Reef Octopus 110INT Classic Skimmer, which utilizes a smaller
version of Aquatrance pump with a 9 watt Aquatrance 1000 has a recommended operating
depth of 7 to 7.9 inches, and again, just under a 1 inch sweet spot. We placed this skimmer in seven
and a half inches of water and measured an average air
draw of 351.12 liters per hour, which is slightly under
the 420 liters per hour rating from Aquatrance. Up next was the Somatic
60S Space Saving Skimmer fitted with its own somatic
pump, made by Sicce, the Sicce SK600 which is the highest wattage pump today at 23 watts and an operating range
of six to nine inches for a much wider operating range
sweet spot of three inches. We placed the Somatic 60S in between those recommended operating depths at seven and a half inches, and found a baseline airflow
of 601.62 liters per hour, which is at the top end of this pump’s air draw rating of 400
to 600 liters per hour. Our only DC powered
skimmer in today’s testing was the Skimz SN127, which has a QPS 1.2 eight to 13 watt pump that’s
housed inside the skimmer body and has a seven inch
to nine and a half inch recommended operating depth. At the highest power
setting for the DC pump and placed at about 8 and
a quarter inches of water we see an average air draw
of 431.64 liters per hour, which lands right in the middle of Skimz’s stated air draw rating of
300 to 540 liters per hour. The Eshopps Azium X-120 is next which features another pump from Sicce, the Sicce SE200 that operates at 10 watts and is recommended for installation in seven to nine inches of water. We placed this skimmer half way at eight inches in the sump and tested the air draw to an average of 168.66 liters per hour, or slightly under the
180 to 200 liter per hour manufacturer rating. We’ve got another Reef Octopus skimmer in the testing pool today with the 110 Super Space Saving Skimmer which uses the same
Aquatrance 100 as the 110INT, however in the space
saving configuration comes installed inside the body
of the 110SSS skimmer body. Again, this pump operates at nine watts and at a recommended
depth of 7 to 7.9 inches with this skimmer placed
at seven and a half inches we tested an average airflow
of 211.74 liters per hour, or about half of the 420 liters per hour rating from Aquatrance. All right, so now with
a baseline established for each skimmer being installed at that recommended operating depth sweet spot, you can definitely see a
pretty large difference in the amount of air
each skimmer is drawing. For example, the Somatic 60 is pulling more than three times the
amount of air than the Eshopps, but it’s also nearly double the size so these are probably pumps
that are purposely paired to skimmer body size. So next, let’s compare
each skimmer individually after we drop below and above the extremes of their recommended levels. Going back to the Reef Octopus 150INT at a depth of about seven inches, or right at one inch below
the lowest operating level, we actually find a very
slight gain in the air draw. That rose by an average of
18.31 liters per hour to 428.28. However, at one inch over the
operating depth of 8.7 inches we ran this skimmer at about 9.7 inches. We saw a slight drop in airflow, down to 396.90 liters per hour, or 13.07 liters per hour
less than the baseline. All and all, I really
wouldn’t consider this one to be much a change,
which might have something to do with the less
than one inch difference between the low and the high
operating depth recommendation. In fact, it looks like
this skimmer would have a three inch operating window
without impacting performance. Next, looking at the Reef Octopus 110INT one inch below the recommended
seven inch threshold in six inches of water we find a significant drop in air draw, down to an average of
85.98 liters per hour, for a total loss of
265.14 liters per hour. When we look to the opposite extreme where we placed the 110INT
in nine inches of water we found a similar story, where there was an average
loss of 104.28 liters per hour down to 246.84. So in this example, both
high and low operating depths had a negative impact on air draw, even with the same
recommended operating variance of less than an inch
between 7 and 7.9 inches. In this case, I’d definitely stick to the operating range of one inch. Onto the Somatic 60S
where we found a baseline of over 600 liters per hour air draw. When we dropped the water
level down to five inches we averaged an airflow of 281.82, or a total loss of 319.8 liters per hour. As for raising the water
level to 10 inches, there was less of a
dramatic drop in airflow to 541.02 liters per
hour, for a loss of 60.6. From the looks of it, this performance is one
of the most affected by changing the operating range, however they started with the 3 inch recommendation operating
window to begin with, so really not a completely
fair comparison. One additional note here
is that even in this tank with freshly mixed
saltwater and no organics, at the 10 inch operating depth I could not get the bubbles below the neck of the cup, which could lead to an
overflowing collection cup when placed on a regular tank, yet the Somatic actually
comes with an air valve so that even with this highest
air draw in this price range, you get the ability to scale the air draw with more or less air to further optimize its performance for your tank and individual organic food and fish load. The Skimz SN127 is next with its baseline 431.64 liters per hour of air draw when installed in that
operating depth sweet spot. Below the extreme lower
end of that sweet spot at six inches of water depth we saw a drop in 107.58 liters per hour, to a total average of 324.06. However, when we raised the water level to the higher level of
10 and a half inches, there was an even more
pronounced fall in the air draw, down to 289.20 liters per hour, or an average loss of 142.44. Just like the Somatic, which had a three inch operating range, this Skimz has a two
and a half inch range, so it’s not surprising that
if you go further than that you see a performance loss. All right, up next we have
the Eshopps Axium X-120 where at eight inches we saw a baseline of 168.66 liters per hour. At a six inch operating
depth that baseline fell to an average 139.74, or a loss of 28.92 liters per hour. However, when placed in 10 inches of water we see a very slight
increase to the air draw by a fractional 5.82 liters per hour, or a total average of 174.48. With differences less
than 50 liters per hour in either direction, I’d say that this particular skimmer didn’t show much of an impact on air draw. However, I did note that at
the higher level installation it was difficult to keep the bubbles at a manageable level that
wouldn’t overflow the cup. The Reef Octopus 110SSS, with the same Aquatrance
1000 pump as the 110INT, this time showed a
minimal performance impact to the low and high operating levels. With a baseline of 211.74 liters per hour, there was only a drop in average airflow at the 6 inches of water level, where we saw a marginal loss of 10.32, for an average of 201.42 liters per hour. As for the higher water
level at nine inches, there was a slight gain
to 217.86 liters per hour, or 6.12 increase total. This performance by far raises
more questions than answers, specifically because
it’s the exact same pump used in the 110INT with a
different body and design, which had one of the
largest affects to air draw from operating depth, whereas in this space
saving configuration, there was little to no effect at all. So what does this all mean, and how can we use today’s
data for optimizing our own protein skimmer’s performance? Well, there’s absolutely
some skimmers whose air draw is dramatically impacted by the depth that it’s operating in, and others seemingly not so much. As we saw from the baseline numbers, there’s definitely a difference across the various skimmer pumps, where some had more than two and a half to three times the air draw over others, possibly hinting that
those particular pumps are being optimized for
that size of skimmer body. We did see a pretty significant difference in two skimmers with differing body styles and pump placement, both utilizing the same exact pump, which might have something to do with the differences in the volute
attachment to each of the pumps, or perhaps the shape and water volume inside their respective bodies. It’s just tough to say for sure. Wattage may also play a factor here, particularly in the case
of the 150INT and 110INT where we saw little to no impact to water depth and air draw to the 150INT that uses an 18 watt pump. However, in a similar design
and pump configuration, the 110INT at a nine watt pump was one of the most
effected by operating depth. This is even with the
sweet spot recommendations for both skimmers being less than one inch from the low to the high end. In that same thought process, the Somatic 60, with
the highest wattage pump we tested today at 23 watts, was also one of the most effected by changing the operating depth. The major difference here being that it allows for a three inch variance in that sweet spot operating range out of the box and recommended
by the manufacturer. Much like we found in the early stages of our salt mix
investigative testing series, we’re just left with more
questions than answers which, I don’t know about you, but for me, it actually makes
this test even more exciting. Meaning, for the next round of testing, we’re going to scale up
the skimmer selection to our most popular six skimmers in the next price range
bracket of $250 to $400 to see if we can start
drawing some parallels to what we saw here today. I can’t wait, because at
the end of all of this I imagine we’ll walk away
with some solid information and guidance as to ways you
can increase the performance of your skimmer on your own tank. In this next test, we’re
going to switch it up a little and rather than rely on the manufacturer’s recommended
operating depths, we’ll test all the skimmers on a scale of five, six, seven and up through 11 inches so you can make more informed decisions of where to install your own skimmer. Okay, so to rate today’s question of does the operating water height matter when installing your
internal protein skimmer? I’m putting this one right in the middle of our reef fantasy to
reef certainty scale at a a five out of 10
because in today’s tests, to some skimmers it did
and to others it didn’t. However, as continue further testing I might have to come back and change that. You know, I love it when
experiments like this lead to further testing, not only because it’s really
fun to watch them progress, but for many of us Reefers,
we get a deeper look into topics that just haven’t been explored before to this degree. So as I mentioned
throughout today’s testing, our salt mix experiments
were a great example of this, where we started with an
experiment on how much your salt mix actually costs per month continued down that rabbit
hole with testing on proper mixing time, mix
saltwater storage length, effects on heat and flow on
mixing and storing saltwater, and even ICP-OES testing analysis to determine if
stratification really exists. If you missed any of those tests, click the salt mix
testing playlist over here to see all the data you need to find the right salt for your needs.


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  2. I have a skimz sn 127 and no matter what height I have it at it is always extremely inconsistent, sometime I will have it on max and it won’t even be close to the top then when I come back water will just be pouring out.

  3. I have a Deltec MC500 in the back chamber of the RSM C250.
    If I leave the air valve 100% open, there is too much air drawn in for the pumps flow rate and the foam collapses. If I turn the knob only halfway through, I get better foam.
    I assume the flow rate of the pump gets split in between water and air flow rate. Too much air to water ratio results in less foam.
    It is true that without any water flow there would be no Venturi to draw air in.

    For me, the main ways to get consistent skimmate in the above setup was to ensure a constant water level with ATO level switch in the back chamber and to keep the air flow tap at 45° out of 90° from fully open to closed.

  4. Gotta say a bit disappointed in your choice of skimmers you use for this test. 3 Reef Octopus skimmers, 2 of which are the same skimmer design just different sizes, and then the other 3 are all really low end skimmers. I know you said you picked skimmers in a similar price bracket but maybe you should have picked skimmers over a wide range of brands instead, Vertex, Nyos, Tunze, heck even the IM skimmers you sell.

    I'm sorry to sound so negative with this comment, I do love the work you guys do, but I feel like the conclusion falls a bit flat due to your testing criteria (i.e. all cheap skimmers). Maybe a test to see if price does make an impact in performance or operation in some way? Does that Vertex Skimmer do the same as the Reef Octopus 110SSS which supposedly has the same tank size ratings, does that Varios Regal brand Octopus really do much difference than the cheaper older models?

  5. Another timely video. My skimmer is a real pain. But the question I have is how does air draw impact performance at removing waste? So we just want the most air draw or does this just mean I have to set the skimmer differently?

  6. I think before tests like this, we need answers about water air ratio first. Is more air draw actually means better performance?

  7. I'm running a Reef Octopus 110SSS but the Somatic had 3X air flow – Does that matter? Would anyone switch skimmers because of this?

  8. Not sure what we are to do with this information?? I have the Somatic 60s. When running within the suggested depth. I'm my case I have a Eshops sump that only gives a seven inch depth. I can not run the skimmer without it dumping tons of bubbles into the sump. As you see in the quick shot towards the end of the video. I got the skimmer just after Christmas. The skimmer is set on top of a ~3.5 rise. So the skimmer is only running in 3.5-4 inches of water with the gate less than 50%. Skimms a ton of dark skim mate. But I don't see it running at suggested depth.

  9. This series of investigates may end up being even more boring than salt. I’m afraid the skimmer shape episodes are going to put me right back in high school geometry class. Hopefully the end results are clear answers and solutions to choosing a skimmer.

    Also, I think the series of investigates should parallel Ryan’s 360 and help him make decisions along the way.

  10. Can you guys test the Vertex 180i skimmer? I think this a popular midlevel skimmer. I would be intrested to see how those higher end Bubbleking skimmers perform.

  11. Btw Randy, I have the Skimz
    SM167. It would also be incredibly helpful if you could explain the operation of the controller on these things and what role they play in the over all functionality of the skimmer.

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