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Today on BRStv Investigates,
do secondary calcium reactor chambers
really scrub off excess CO2 and elevate pH?
(upbeat music)
Hi, I'm Randy your host
for the YouTube series BRStv Investigates,
where we take popular reefing theories, methods,
questions, and products and dive even further
than what the manuals and packaging will tell you
in order to put them to the test
in real world environments, rate them on our scale
of reef fantasy to reef certainty,
and then share with you,
the reefing community, what we find.
Today we seek to answer two questions.
First, will secondary calcium reactor chambers,
intended to off-gas excess CO2,
really result in higher pH effluent,
and related to that, higher pH for the tank?
Meaning every calcium reactor
has a primary chamber that recirculates CO2
and melts the calcium reactor media.
However, some reactors have a second chamber of media,
designed to scrub excess CO2 in the solution
before it gets to the reef tank
and we wanna know if they really work.
The second question we'll answer today,
is will the secondary chamber increase the potency
of the calcium reactor's effluent being dosed?
Which means we'll be testing the alkalinity
before and after the secondary chamber
to see if there's any differences.
All right so why should this matter
to reefers and their tanks?
For some reefers using calcium reactors
it's not uncommon to see the regular pH swings
of their display tank fall slightly after dosing the low pH
of the calcium reactor effluent regularly.
Along with that there many be some additional benefits
from having more CO2 contact time with more media
outside of simply scrubbing off excess.
For example, if we find that not only does pH
go up after the secondary chamber but also
our alkalinity increases for more contact time,
then some might consider that a win-win.
To that effect we plan to test today's question
using a vertex calcium reactor filled
with Two Little Fishies reborn media,
set to two common pH set points of 6.4 and 6.8,
which represent the lower and upper pH set points,
that most reefers use,
with flow rates of 20, 60, and a hundred mils per minute
and watch for any impact the contact time may have
on changes in pH between
the primary and secondary reactor chambers.
Since the solution inside the reactor is recirculating,
we'll use the pH set points as the measure of pH
before the secondary chamber,
and to test the pH after the secondary chamber,
we'll use this inline pH probe setup
on the effluent line with a pinpoint pH monitor.
Each of these points are using the BRS dual junction
lab grade pH probes.
We also plan to test for any changes to alkalinity
before and after the secondary chamber.
So I've rigged up a three way ball valve
before the chamber to draw a sample of solution
directly from the main recirculating chamber
to check the alkalinity before it gets
to the secondary scrubbing chamber.
Okay so let's look at the results from a couple
of different view points first,
we'll see if there was any change to the pH
from the set points of 6.4 and 6.8,
after the secondary chamber and a different flow rates
of 20, 60, and 100 mils per minute.
Starting with the data of the pH set point at 6.4,
which is likely on the lower end
of what most reefers typically choose.
At 20 mils per minute after the secondary chamber
we see a slight pH increase of seven hundredths to 6.47,
and I'll save you the suspense,
the same 0.07 pH increase remained constant
for all three points even when the flow rates
were increased by three and five times
at 60 and 100 mils per minute.
For the second pH test point we chose 6.8 for a reference,
and monitor the pH after the secondary chamber,
where we found again a slight increase
at 20 mils per minute flow rate,
from 6.8 in the main recirculating chamber to 6.85
after the secondary chamber.
With the flow rate cranked up to 60 mils per minute
we gain another one hundredth of its pH point
to 6.86 and at 100 mils per minute we reach a pH of 6.87.
So what we're seeing here probably doesn't seem
like much increase at all,
but for some of those reefers tanks that have pH hovering
right around that upper end of 7.9
when running a calcium reactor,
adding a secondary chamber might be what gets you to 8.0.
So after testing pH before and after
the secondary chamber, we also thought
it would be interesting to see,
if there were any changes to the alkalinity concentration
in-between the two chambers and actually
I was pretty surprised at the results.
Starting with the 6.4 pH setpoint at 20 mils per minute
flow rate before the secondary chamber,
we saw an alkalinity of 35.4 dKH.
However, after it traveled through the small
secondary chamber filled with the same media,
we see that it gained about 8.2 total dKH for 43.6.
When we increased the flow rate to 60 mils per minute,
we still see an increase in saturation,
just less dramatic from 35.6 to 39 dKH
for a three dKH total increase,
and at 100 mils per minute an even less pronounced increase
from 32.8 dKH before the secondary chamber to 34.6 after.
Meaning that for all three flow rates combined
there is a total average increase of dKH
from the first chamber to the second.
That is about 13 percent more concentrated.
So as we can see here it seems, that the longer contact time
the calcium reactor solution has in the secondary chamber,
the more it continues to dissolve media
and thusly we see an increase in total max saturation.
As the flow rates increase, meaning less contact time,
those saturation levels move closer together.
Moving on to the 6.8 pH setpoint with the same flow rates,
we see that at 20 mils per minute we have an average
of 21.6 dKH before the secondary chamber,
followed by a slight increase to 23.2
after the additional contact time
for a fold change of 1.6 dKH.
At 60 mils per minute flow that change falls
to 1.1 dKH increase, where we had 20.4 dKH prior
and 21.5 after.
At 100 mils per minute again the increase
is less dramatic from 17.8 to 18.7 dKH
for a less than a single dKH point increase.
The total change to concentration across
all three flow rates at this pH point was
a total increase of about six percent.
So all in all the increase in alkalinity
was less pronounced at a higher pH setpoint.
So to answer today's question of
will the secondary calcium reactor chambers,
intended to off-gas extra CO2,
really result in higher pH effluent?
I'm giving this one a four on the reef fantasy scale.
Although there was a slight increase in pH
from the main chamber to the secondary chamber,
it really wasn't as impactful as some may thought,
it would have been.
Perhaps small changes in pH below a 10th of a point
may help a small group of reefers,
who are looking for incremental changes,
such as from 7.95 to 8.0,
but in the long run I think those, who are using
a calcium reactor and struggling with low tank pH
to begin with, would likely see ways to increase
that effluent pH by larger margins
than hundredths of a point.
As for the second question of is there
any difference in max saturation
between the main chamber and the secondary chamber?
In today's testing we found
a significant increase in the alkalinity potency
after the secondary chamber at lower pHs
and lower flow rates, which has less of an impact
as you increase both pH and flow.
So what can we take away from today's testing data?
Again in those cases where you're trying
to edge out a small increase in your tank pH,
where your display might be on the verge
of being too low or if you're on the upper ends
of a pH point and are looking to gain a little edge,
you could add on a secondary chamber
and make a small impact.
However, for those who are looking
for more significant changes to pH by more
than a single tenth of a point,
like from 7.7 to 8.0 or higher,
you'll likely be better served looking at other ways
to increase your tanks overall pH, such as
better ventilation or opening a window in the room,
supplementing your ATO with Kalkwasser,
adding a refugium or even adding a C02 scrubber setup
to your skimmer.
For those reefers looking to optimize
their max saturation levels of calcium reactors effluent,
adding on a second chamber will do that,
most notably when running the reactor
at a lower pH and lower flow rate.
What's next in our BRStv Investigates for calcium reactors?
Well, we definitely want to explore some other approaches
to increasing the effluent pH, so we'd love to hear
your ideas for things to test in that regard,
but before we do that, we thought we'd test
the max saturation levels of a couple of other popular
calcium reactor media types with CaribSea ARM coarse media
and Brightwell's CoraLazarus high purity reactor media.
My personal guess is that they will end up
being relatively similar, but they are very clearly
different types of media than the Two Little Fishies Reborn,
we've been using.
So we'll have to test to know for sure.
Thanks for watching this BRStv Investigates.
Click the top link to see our initial max saturation test
with Two Little Fishies Reborn media,
or the bottom video for a how-to on switching
to a calcium reactor from two-part.
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