FAQs on Marine Alkalinity
Articles: pH, Alkalinity,
Marine Alkalinity, Understanding Calcium & Alkalinity,
Marine Alkalinity 1,
Marine Alkalinity 2, Marine Alkalinity 3, Marine Alkalinity 4, Marine Alkalinity 5, Calcium and Alkalinity, Phosphate,
& FAQs on Alkalinity: The Science of Alkalinity,
Importance, Measure, Sources,
Use of Additives/Buffers, Products by Name: & FAQs on pH: Importance,
Science, pH Measure/Test
Gear, pH Controllers & pH Buffers/Buffering,
pH Anomalies (Troubleshooting/Fixing), &
pH Products by Name, Manufacturer,
180G mixed reef with sudden low pH issues, pls help!
Hello! Long time listener, first time caller. I have a problem that I can't seem
to find the answer to and its starting to have an effect on my aquatic charges
as well as my psychological well-being. My setup is a 180g mixed reef (fish,
LPS, SPS, softies). I use an Vortec MP40 and a MaxiJet 400 to supplement the
circulation that comes from my Reeflo Hammerhead.
For lighting I have 3x Chinese Black Boxes. I use a protein skimmer, a
Phosban reactor and NPX biopellets to control waste
<Mmm; these chemical media do have downsides>
and, occasionally, a filter sock.
<Needs to be cleaned/switched out; daily>
My problem is my pH.
<More likely alkalinity, alkaline reserve eh?>
I have an Aquacontroller that have used for several years to provide constant,
real-time pH and temp readings. It has been a great way to quickly assess the
goings-on in my tank between testing. Recently it required a cal and afterwards
the pH was much lower than I expected. At first I suspected a bad cal, but a
second electronic meter as well as the
API drop test (and a THIRD lab grade electronic meter) corroborated the result.
Here is a 'snapshot' of my parameters after my photoperiod:
<This is low.... I'd keep 8.2 at a min.>
I'm sure a pH of 7.85 by itself doesn't spell immediate disaster, but at night I
am dipping much lower, like 7.65 just before the lights come on. As a way of
"QC'ing" my probes I mixed a new batch of Red Sea Coral Pro sea salt @ 1.025 SG
and boom, 8.2 pH. Both my total and carbonate hardness test kits read in the 12
dKH range. I was running a CO2 reactor, a habit I
have suspended until I get my pH squared away again.
I tried mixing 2 tsp of Kalk in 1 gallon of RO/DI water and dripping it
all in at night, to very little effect. I'm getting a white haze on my glass, so
I'm thinking I am hitting saturation for my nocturnal pH.
<Mmm; yes. I would NOT use Kalk here>
My corals look stressed and I've started to lose some of my SPS (1 bleached,
lost tissue, died, 2 bleached but are... recovering?, 2 sloughed off ALL tissue
overnight). Most other LPS/softies/inverts/fish look and act fine but I'm
getting very little growth/polyp extension.
<Water changes for now.... and using (for the short term) a commercial
product that is heavy on the carbonate side. See SeaChem's line here>
Apart from RO/DI & Red Sea Coral Pro salt 15% water changes, I've tried
adding baking soda,
<Mmm, bicarb. won't raise the pH here past where it is>
Kalk, 2-part, and aerating the tank with outside air (my sump is in my garage
with an open window, but I've also run my skimmer intake outside as well).
Interestingly my last 20g water change with 8.2 pH water seemed to drive my pH
down about 0.1... I don't want to add anything more because, simply put, I don't
think my water can hold it.
My tank in its current manifestation is about 2 years old but some of
the live rock and sand is as old as 10. I've changed some pieces of rock and
some sand out periodically, but I'm sure some of the old stuff is still in
<I'd switch out more>
I was using crushed aragonite
<And use crushed coral>
at about 2-3 inches, but I switched the right half of my tank to a finer grain
size when I re-re-homed a friends corkscrew long tentacle anemone.
I'm wondering now if the particle size on the remaining aragonite on the left
side is too large and harboring too much funk.
<Could be a factor>
It isn't visibly dirty, but I'm sure if I stirred it up there would be a
Do you have any ideas regarding my pH situation?
<Oh yes; all sorts. If it were me/mine, I'd do the above AND be reading re RedOx
measure.... I'll bet yours is bunk low>
I can't imagine a 7.6 pH is conducive to coral growth and development, and the
sudden onset of the situation accompanied by my loss of coral has me in a panic.
The situation only seems to be worsening and I'm not sure what to try next.
Matt, St. Pete, FL
<Consider the changes mentioned and the addition of an ozonizer. Bob Fenner>
Re: 180G mixed reef with sudden low pH issues, pls help!
Thank you so much for the ideas, I think I will remove the crushed coral (not
aragonite, sorry) sand I have and replace with 2-3" fine grain,
clean the live rock, then do a significant water change (50%?).
<Okay; with pre-mixed>
I've ordered an ORP module from Amazon, but finding an ozone generator has been
<Oh; they're about. Try Dr.s Foster and Smith>
I only use my filter sock intermittently, 1 day at a time so that shouldn't be
too much of a problem. I just use it during cleaning and water changes to catch
what I kick up.
With respect to the Seachem product, would you recommend the Reef Carbonate
or Reef Complete, or the Marine Buffer, or some balanced addition of multiple
products? I ask because I am reluctant to ever just add one side of the equation
and I didn't quite follow that piece of your advice. Should I be aiming
for a higher KH
<Mmm; not higher, but a mix of agents that will trend to keep the pH higher>
or did you mean for me to just try a different supplement for now?
<Going forward; we need to find out what the real source/s of lowering pH are at
work here and solve them. I'd pull the Carbon pellets and Phos remover for now
What goal should I have in mind, I guess is what I mean.
<.... a pH twixt 8.2-8.4... >
Also, I try and use the Phosban and NPX sparsely, but would you recommend I
discontinue their use?
<Yes; these products may well be nicking your ORP to nada, dropping not just pH,
but the systems capacity to support life en toto>
<Welcome. Bob Fenner>
Reef Tank dosing issue 10/8/14
Hello crew it has been some time since I wrote last but I need some help
because I find myself scratching my head and running in circles... A
little history of my reef tank and what it contains, ( this will be
long) it is a 75 gallon reef with thirty gallon sump, reef octopus
skimmer, uv sterilizer, carbon reactor, gfo reactor, ATO system, reef
breeders photon leds, main return pump is a Mag drive 9.5, and I also
have Hydor power head in the tank 1150 gph , I have a very very large
hammer coral with 100 plus heads, softball size Pectinia, large Acan
colony, large brain coral, several sea fans, two large Stylophora, one
large Pocillopora, one large millepora, and a 5 inch derasa clam, shame
on me but I have never really tested my systems but I never really
needed to, I did my weekly water changes with high quality salt and
never had issues for over seven years, however my eyes started telling
me something was off, coralline algae was bleaching and died off, my
clam was beginning to gape and growth disappeared, and corals lost there
vibrant colors, no losses thank god. I ordered new Red Sea foundation
test kits, my initial parameters were calcium 300, alk 7.6 and Mag of
1180. I spent literally days reading and attempting to understand the
mg/ca/alk balance and think I have a decent understanding of it after
relearning chemistry. I made the decision it was best to raise each
parameter individually in small amounts and then begin a two part dosing
system. This is the part I can't figure out, I raised my Mag to 1360, my
calcium to 420 and they are holding steady with no changes, but my alk
will rise to 8.1 after one dose but drop back to 7.6 with in 24-36 hrs ,
I am hesitant to raise it any more at one time.
<The Calcium is precipitating the difference out>
I was dosing every other day to raise it and then once I reached the
desired levels I was going to switch to the two part to keep it there.
<I would switch; go w/ the two part now>
There has been no precipitation that I have seen, the corals and clam do
look much better and the clam is no longer gaping and has new growth
however no new coralline algae that I have seen. Is it possible my tank
is using this much that fast?
I have been at this for three weeks and I have no clue how to raise the
alk up to the 9 area
<Don't obsess re... allow the [Ca] to drop to about 380 ppm, and all
will be well>
and keep it there so I can start dosing the two part daily, how would
you suggest I go about this issue? Can I raise the alk to 8.1 and dose
the 2 part at the same time and continue raising the alk every offer day
until I get to my target of 9.5 alk?
<Best to not try doing both simultaneously. One approach OR the other>
<Welcome. Bob "Stoichiometry" Fenner>
DKH, up and down! 7/14/13
Hi crew! I have another chemistry question for you all!
My water parameters have been fairly stable for 2 months in my new 75
gallon reef tank.
a.. Mag 1400
b.. Cal 440
c.. pH 8.3
d.. Sa 1.023
Except for the DkH. It drops from 8 to 6 in a weeks time.
So I dose with Kent's Supper Buffer DkH to bring it back up to 8.
<I'd switch to SeaChem's products. Better value>
I have a very low bio load with 2 brittle stars, 3 Mexican Turbos and 3
Chestnut Turbo snails, 2 Chromis, one small carpet anemone and 2 tiny
I run a Remora skimmer
hob filter w/Chemipure elite
and a refugium with Chaeto and Miracle Mud.
<Mmm, this last... increasing reductive "behavior" in your system
I use RO/DI water only, top off every 5 days and change 15 gallons every
So, what am I doing wrong?
Thank you for helping me achieve my dream tank! This will be my third
<I'd keep using a source (commercial) of carbonate, bicarbonate... added
to your weekly water change out water... and not be concerned. Would
leave in the Mud, would switch to SeaChem... Bob Fenner>
Re: Dkh, up and down!
Bob,... not sure what you mean by "reductive behavior" .
<Mmm, as in reduction/oxidation.... "Acidic"... all captive systems
tend/trend toward acidity... the alkalinity being "eaten up" with
Does this make sense? The net processes in our systems "run down" the
pH... hence the need to have countervailing strategies... alkaline
material (rock, substrate), water changes...>
Do you mean that Chaetomorpha AND Miracle Mud in the refugium is causing
the fluctuating dKH?
<Mainly the mud.... the organic component; yes>
Re: Dkh, up and down! 7/16/13
Ok Bob, that does explain the process, but still not entirely sure what
Below, you said to "leave in the Mud" but if the mud is contributing to
the "reductive behavior" why have the mud at all?
<For all the good/things it does>
Or, for that matter, why have a refugium?
<... "see WWM re">
Does this system NOT contribute to oxidation?
<Yes; both reaction series>
Wow, look what I just found!
http://www.wetwebmedia.com/redox.htm Going to read this now!
<Heeeeee! A panoplia of bland statements on a quite esoteric, but VERY
Please bare with me Bob, I do NOT have a PhD,.........yet!
<Me neither. B>
Re: Dkh, up and down! 7/16/13
Alkalinity Too High... too much added to a one month old
I have a 110 gal FOWLR tank, (I used to have some
corals and sold them from a previous 42 gal and a small lettuce coral
got left behind and is in my new tank)
I believe this happened to me.
Buffers alone are not generally a good method as they raise pH
little, and result in excessive alkalinity. Unfortunately, the labels on
many commercial buffers are written in ways that convince aquarists that
the pH will be fine if they just add some buffer. More often than not,
the pH is not improved for more than a day, and the alkalinity rises
beyond desired limits.
<Can; yes... And I'd emphasize/state that this is not the case w/ all
buffer/ing products. Some manufacturers are more "completely honest". A
My PH is at a desired level now but my alkalinity is too high
now. My calcium was a bit too low so I added 2 caps of
<... not a fan of this (or many) Kent products>
I was going to test the calcium tomorrow and see where it stood. I
I was just going to leave the tank alone to settle down once the calcium
is right. All my other water parameters are good
Am I on the right track or is there anything I should do about the
<... Depends... on what the alkalinity is due to... carbonates,
bicarbonates... When, where in doubt, best to do either a massive
(pre-made) or successive water change/s... to dilute the "Dead Sea
effect" of having added (so many, much) products>
My tank is a little over a month old
<?! You shouldn't have to be adding anything here>
and my first water change/maintenance is scheduled for 1st part of July. I
can ask for it sooner if necessary. I cant lift the canopy off myself so
I have to have someone do it.
<Mmm, do look about re gear that can help you w/ automating lifting this
top... there are hinged arrangements, even infra-red signaled motorized
Thanks so much.
<A pleasure to share, help. Bob Fenner>
Just wanted to double check with you as I have read it should not be a
problem. I run a FOWLR system and I recently started testing for
Alkalinity and it was off the scale of over 17dKH. All my fish are
fantastic, even delicate species like Yellow Cubicus boxfish/Blueface
angel etc and I think this is due to an overdose with Seachem Marine
Buffer. Unless you recommend something different I am going to leave the
system for the natural biological cycles to bring down the alkalinity
and use smaller doses next time.
<No danger and I would let it take it's course, regular water changes
will help lower the dKH. Do not add any buffers during this
period. James (Salty Dog)>