FAQs about Dosing Carbon
Related Articles: Controllers, X10 Controllers, An Economical
and Functional Approach to Aquarium Timers, By James Gasta,
Marine System Heating, Coldwater Systems,
& Water Changes for Marine Systems
Tapwater, Marine Water Quality, Marine Plumbing, Heating 1, Chillers, Water
Carbon Dosing Problems 3/7/12
I've been using Red Sea's No3:PoX4 for
about a year now with decent results in the reduction of my phosphate
levels. My tank looked like Astroturf before using it and then upon a
few weeks, the tank cleared up with 0 phosphates as result. The caveat
though is that my nitrate levels haven't dropped at all with the
rating being at 50+ ppm until I changed around 50% of the tank's
water several weeks ago. Now the nitrates are around 20-30 ppm via my
API testing kit.
Also, I've noticed a small steady measure of ammonia within my tank
that seems incongruous to my stocking level, age of the tank,
<Large populations of nitrate reducing bacteria can lower the oxygen
level available to the denitrifying bacteria.>
Lately I've also noticed a negative swing in the pH whenever I add
the dosage (20 ml) for my 200g tank to the point of needing to add
Sodium Carbonate to balance it. I haven't measured the pH in a long
while as I assumed it would be balanced on its own through the water
changes, so the pH problem may have been around for a while.
<Never assume anything in this hobby. The pH can drop slightly
on initial dosing but not to a dangerous level.>
Lesson learned to measure this twice daily from now on.
<Better just to get an electronic pH monitor.>
I have no nuisance algae currently however as I stated, my nitrates
continue to hover around 20-25 ppm.
<May want to try a different test kit or take a water sample to your
LFS for comparison.>
I have no corals currently as I wanted to get everything under
control before I add corals, fish, inverts, etc. I hypothesize that I
may have a bacterial imbalance in the tank, but would like some advice
on what is going wrong within the tank itself. I think I might have
gone to near Ogliotrophic levels at one point and then didn't
reduce the carbon source enough resulting in a shift towards what I
.15 ppm Ammonia
<I'd confirm this as well.>
.20 ppm Nitrates
pH- 8.0 steady, however it swings low after the introduction of the
carbon source, it measured as low as 7.4 yesterday when I got home from
Carbonate Hardness - 11
5% water changes weekly
Skimmer rated for 300g
<What brand, what model. An efficient skimmer is very
important when carbon dosing.>
Pump is rated at 2500gph + 4 Powerheads
4 surgeons (all around 4 inches), one dwarf angel, mandarin, clown and
I feed twice daily with a small amount with the addition of Nori for
Calcium Reactor present, however very low usage.
180lbs of Rock
2.5 years on the tank
Canister filter with Ehfisubstrat to act as a secondary filter (I clean
<No sump mentioned? High oxygen levels are important when
The bacterial bloom will reduce oxygen levels and cause the effects you
are seeing. An efficient protein skimmer will provide some
oxygenation but use of a sump in tandem with the skimmer would be much
Also, My Achilles Surgeon despite having a voracious appetite has had a
perpetual pitting around his head and on his cheeks indicative of HLLE
(I assume) which I would surmise is due to the water quality.
<Water quality, O2 level, and diet all play a part in reducing
HLLE. In nature, tangs are found in oxygen rich waters.>
(All fish were quarantined for 4 weeks via hyposalinity and
medicated food to remove possible internal parasites). For now, I think
the best course of action is to halt the carbon dosing and see if the
conditions improve, but I would like a chemistry based understanding
solution of what's going on currently in my tank if you can provide
<Based on your info I believe your O2 level is low and your skimmer
isn't efficient enough to undertake carbon dosing. Skimmer
ratings and actual capabilities come into play here.>
Another tertiary detail that may have an impact. I was using old
shifted halide bulbs for a while (6 months)+ and then temporarily
switched to T5's until I finished building my LED setup which was
established Saturday. I don't think it would affect the issues
above, but I can't say for sure.
Thanks for any help that you can provide
<You're welcome and thank you for a nicely written query.
Based on your reply to this, I may be able to suggest other options for
you. James (Salty Dog)>
Re: Carbon Dosing Problems –
To clarify what I forgot to include:
I am using a 60g gallon sump.
I purchased a pH monitor last week which should arrive late this
This morning when I came off of shift, I used two different nitrate
testing kits. The API which I have been using and the Red Sea Pro
The API again returned 20+ ppm while the RSP returned roughly 15ish ppm
based on color interpretation. I'm debating on buying the
Electronic American Pinpoint system to use as a testing system
from now on.
<I'd favor the reading of the Red Sea kit.>
The Skimmer is an "AquaMaxx Cone Series In-Sump" series.
<And I believe your model is rated for tanks 100-300 gallons based
on the latest model I viewed. If you have a heavy bio-load,
it's likely borderline. Do you clean the reaction chamber
Doing so increases efficiency.>
Specifications per the manufacturer are:
Footprint: 13 x 8 Inches
Pump(included): Sicce 2.0
power consumption: 22 Watts
Intake: 720 LPH
Chamber Diameter: 6 Inches
Height: 23 inches
Recommended Water Level: 8-10 Inches
Outlet Size: 1 Inch Quick-Precise adjusting valve
Volume rating: Up to 375 Gallons
A bit on the skimmer, my tank water evaporates very quickly
causing the water level within the sump to drop an inch or so every
10-12 hours. I have noticed within the past week that the water
dropping dramatically reduces the effectiveness of the skimmer.
<Oh yes, that is why ATOs are nice to have.>
To compensate I am adjusting the skimmer to skim as wet as possible
whenever I see the foam head drop within the edge of the cone. I
suspect not being on top of this earlier may have been a key source of
<Likely, not much use if no protein is removed on a continual
Now with adjustment, it pulls out at least a cup full of light
green/tea colored fluid a day. I am going to devise an ATO system
from my RO/DI to facilitate this as well.
<Now you're talkin'.>
The API test kit for Ammonia is quite old. I will purchase a new one.
I've been reading some anecdotal evidence regarding the inaccuracy
of API kits and will switch to a different brand or electronic
Tank coverings are pieces of egg crate that are cut to fit the open
Sand bed is roughly 1/8" of an inch of Oolitic sand.
There appears to be a haze within the water under the new lights which
I haven't been able to observe before which may be bacterial
<Very likely an over abundance of bacteria which can be caused by
over dosing carbon.>
The Achilles Surgeon as well as the other fish are fed a mash of mixed
seafood, Nori, laver, dulse, Vita-Chem, Selcon, garlic and Vitamin
I agree with your statement regarding issues concerning low O2
and issues with the skimmer.
<You might want to try a different type of carbon source. Some
work better than others in many cases. Every system can be unique
in that regard. I've been using Tropic Marin's Bio Actif and am
very pleased with the results. Nitrates staying 5-10ppm with a
normal weekly dose. I have also tried the Brightwell product and
had the same results you experienced with the Red Sea brand.>
Thank you for your reply and your assistance.
<You're welcome. James (Salty Dog)>
Cloudy Tank 8/18/11
Third time writing in! Contacted you last time about an algae problem
which has since been cured. Thanks for the help!
My current issue is with a slightly hazy (cloudy) tank. I'm
had problems with low alkalinity and high calcium in the past, but pH
was fine. I was correcting the problem by adding baking soda.
Everything was just fine for awhile. About 1.5 months ago I got some
new baking soda from a friend and added it to the tank as per usual.
The next day, the tank was quite cloudy/hazy. I assumed I had overdosed
and let the tank take care of itself for a few days. Nothing
changed...perhaps slightly less cloudy, but still hazy.
<I'm not a fan of baking soda, can be dangerous if not
I read that it should clear-up by itself and there might be a snowstorm
and precipitate on the rocks etc. So far, I've had no precipitate
at all. I also have some brown hair algae growing in the tank recently,
since fixing my last algae problem (red slime). Don't think its
Over the past 2 weeks I've been doing 20% water changes every other
day, tank is still cloudy. I tested before starting the water changes
and both alkalinity and calcium were low (6 dKH and 300ppm),
<A dKH of 6 is not that low.>
but pH fine (8.3). I also tried dosing 2-part alkalinity and calcium,
which worked a little ...
<Dosing both parts at the same time can cause cloudiness. Best to
dose part B the following day.>
but Alk quickly went low again; this was before water changes. After
doing these water changes calcium has climbed, but Alk is low still. Ph
is fine ... but my magnesium is very high. Before starting water
changes it was at 1,500ppm, its now at 1,650ppm.
<The high magnesium will have an effect on dKH.>
I am not adding anything to my tank right now except 2ml vodka
a day (tank volume 110g).
<You might be experiencing a bacterial bloom from the vodka dosing,
stop dosing for a few days.>
I'm using the same salt mix I've always used (marinium), so not
sure what's going on here. I can't find much info on high
magnesium levels, but I'm guessing this, alkalinity and calcium are
all doing something strange here.
<I just wrote a short article on magnesium which Bob recently placed
on our site. Do read here.
I've also lost about 3 snails, 3 crabs, a cleaner shrimp and a
blenny since the cloudiness. Before this, lost almost nothing in the
past 6 months except the occasional hermit crab from fighting. Only one
coral and its not too happy at the moment.
<Likely due to the 0 nitrate level, corals do benefit from some
nitrate present, 4-5ppm would be ideal. Is best to correct one
parameter at a time and then move to the next. Your dKH is fine where
it is for now. Do not add any more magnesium to the system until levels
drop below 1250ppm. You are creating several parameter changes by
trying to deal with all at the same time which is likely contributing
to your problem.>
All the fish seem to have Ich suddenly as well, with no new pet
<Likely stress induced re above.>
I also found a pump leaking about 100v of electricity into the tank,
this was rectified yesterday. Tank still hazy, any ideas would be very
much appreciated! Thanks!
<You're welcome. James (Salty Dog)>
Temp: 26 C
Alkalinity: 6 dKH
Re Cloudy Tank 8/18/11- 8/22/11
I've stopped the vodka for 4 days now, the cloudiness has not
gotten any better. Possibly worsening slowly (though I think its always
getting worse when I don't try water changes). Coral is looking
worse, getting puffy around the base and tentacles not extending much
at all. Fish and crabs also not looking very happy; still eating, but
not as much as before. Almost all covered in Ich.
<Definitely something amiss in water quality.>
I've never added Mg to my tank, the levels seem to be increasing by
<Impossible, do compare readings with another kit, at your
I'm thinking when I added the baking soda, everything went way out
<Easily could have. I would not use baking soda.>
I'm starting to think it wasn't even baking soda ... baking
<Yikes, baking powder contains sodium bicarbonate as does baking
soda, but it includes an acidifying agent, not good and can cause a
drastic short term drop in pH.
You have too much money invested in your livestock, and trying to save
a dime by using baking soda/powder does not make good sense....akin to
walking over a dollar to pick up a nickel. Much safer to use products
designed for marine systems.>
I've done something like 4 x 20% water changes, but the cloudiness
has not gotten any better. Maybe in the short term, but then it seems
to get worse again. What do you think I should do?
<I would get a Polyfilter and ensure water is flowing through the
Continue with water changes, should see an improvement in a few days of
using the Polyfilter. Is there any chance a containment may have gotten
into the water? Have you tested for ammonia/nitrite?>
All parameters look fine, except dKH a touch low, calcium low and
Magnesium sky-high. Thanks again for your help
<You're welcome. James (Salty Dog)>
Re Cloudy Tank 8/18/11- 8/22/11- 9/6/11
Just an update. I wasn't able to get the Polyfilter, so put in some
Kent Marine carbon instead. I followed this with a large 40% water
Before I got to this point however, most of my fish, crabs and snails
All covered in white spots, likely from the stress of the water
conditions. The Yellow Tang which was the first infected, has made a
full recovery and is completely clear of white spots (at this time) and
My coral is looking back to its original state with no signs of any
All in all, everything seems to be almost back to normal ... still no
idea what happened though.
<Strange things can happen for no apparent reason.>
All my levels are good, except alkalinity a touch low still (6 dKH),
and Magnesium still high (1,600ppm) but coming down with water changes.
No vodka addition in a few weeks and ammonia, nitrite, nitrate and
phosphate are still reading 0 strangely enough. I do have a brown hair
type algae growing over the sand and in high-flow areas. A week ago the
entire sand would go from clean to brown in 12hrs .... its now slowed
down quite a bit after I scrubbed most of it off and doesn't seem
to be coming back. Needless to say, the skimmer has been going
absolutely nuts for the past few weeks with tons of skimmate.
I'll continue with the carbon and water changes until all levels
are normal and skimmate goes back to normal. Still have no idea what
happened, besides the overdose of alkalinity; to cause this.
<Or overdosing the vodka.>
Perhaps something additional was introduced to the tank without my
knowledge, who knows. Just wanted to say thanks for the help!
<You're welcome. James (Salty Dog)>
Sea Hare Demise (but which sea hare?)
I have need of your professional help I am currently using an
Aquaripure system dosing with vodka on my 90 gallon
tank, all my parameters are perfect. have been dosing since December
<<There are risks and rewards to this, it's one of those
'reef-trendy' hot-topics, the biggest risk is in testing,
it's difficult to tell how much Vodka has actually diffused into
the system and there in lies the problem of over dosing which can lead
to oxygen depletion and bacterial blooms, especially if the carbon
levels in your tank are low to begin with.>>
I recently noticed hair algae growing in tank
<<Hair algae as in cyanobacteria? Refer to my previous
so I purchased a sea hare. Currently the tank houses a mated pair of
tomato clowns (spawning) 5 solon fairy wrasses(female) 1 male solon
wrasse, fox face, deep water coral beauty, assorted mushrooms, zoos and
palys hermits 2 sea Cukes, clams, snails and sea stars. I have not lost
any of my fish stock since started dosing. placed a sea hare in on
8-25-2011, it started eating hair algae immediately. As of 10:30pm
8-25-2011 was still cruising the tank returned home from work at 8:00am
8-26-2011 and sea stars and hermits were having a feast. Could the
vodka have caused it to pass on. Your input and a reply would be deeply
<<First off Bill, it's very important to identify the animal
you purchased there are several Opisthobranchia (Sea Slugs) sold into
the hobby as 'tropicals' that have no business being there to
begin with. The first is found off of the southern pacific coast of the
United States down into Baja California Mexico, this is temperate, read
cold water, species that does not survive long in reef aquariums as
70*'s F is considered to be at the highest extreme of the
temperature they can handle. They are more accustomed to temperatures
in the high 50's to mid 60's. I help care for three of these in
a Tidepool display and the temperature is set at 65* and it's
important to note that the husbandry staff considers that temperature
to be the 'summer' setting, even at that a chiller is still
needed. They also get large, 15', several pounds. The latter
sea-hare is the tropical Aplysia dactylomela, they are better adjusted
for captivity than their temperate cousins, and typically don't
grow larger than 6'. They are however still difficult to care for
in home aquaria as the survival rate, due to the way they are captured
and shipped is relatively low. Even worse these two species to the
untrained eye look very similar when both are but a mere two inches or
so, the size at which they are most commonly sold. As far as what is to
blame it's difficult to say as none of your inverts, especially
your echinoderms (sea star/cucumbers) appear affected by the vodka
(though circumstantial evidence certainly says your organic carbon and
oxygen levels may be). An animal that perished this soon was either
already ill/injured or something environmental in your tank or the
acclimation process caused its health to deteriorate fast. I would
first start by trying to ID what species you have, as for the hair
algae, it sounds like the symptom of another larger problem, rather
than being the problem itself. >>
<<Anytime, and please remember to capitalize 'I' and the
beginning of each new sentence, and proper nouns (your name). Proper
grammar and spelling is really all that we ask for in exchange for this
free service, as we share your experiences with others in our FAQ's
in order to spread the knowledge. When we get an email with poor
grammar we either reject it (and you don't get the help you need)
or we the crew are forced to correct it taking up time that could be
used to help someone else with their pets. Thanks for your
understanding; I made most of the corrections this time for you, as I
wanted you to get a timely response. Our 'boss' is a stickler
for this and has passed on this 'pet-peeve' of sorts to us
minions. In the meantime please also refer to our article and FAQS on
RedSea P04X + NP Biopellets = THE
Hope all is going well, or at least better than it is for me at
I try to keep this as short as possible. I have a 200g reef
system full of softies Â Kenya tree, and a huge Medusa
coral ( sorry I donÂ¹t know scientific names) all were
doing great. Really great Â medusa coral was well over
2' high and wide and was my showpiece moving back and forth
with the Wavemaker.
My nitrates were at around 20, so I thought id try RedSea P04
reducer to reduce my water changes . I was using it in my auto
top up for about a month Â took a holiday to Canada
saw the great success and high stocking levels there with SPS
corals and quarterly water changes and thought id try some of
that. They were using NP biopellets in a reactor, so as soon as I
got home I tried the same. But something went wrong.
I thought as the biopellets are "solid vodka"
<Well, sort of: http://glassbox-design.com/2009/np-bio-pellets-carbon-dosing/
feeding the bacteria that reduce nitrates, switching from liquid
dosing would not be a problem as its the same bacteriaÂ. So
I plugged in the reactor with about quarter of the recommended
dosage. All was fine for about a day until the auto top off added
more of the RedSea product. I didnÂ¹t think this would
be a problem as I had already heavily diluted the top up water.
What a mistake.
By the next morning the tank was cloudy ant my medusa was
splitting at the trunk (see photo). Over the next few days it
totally fell apart. Inside was like black soot mixed with sawdust
(calcium I guess) and felt the same Â you could
literally pick out clumps of the stuff Â it wasn't
slimy. Skimmer pulled out about 4 pints of gunk within 48hrs
I've siphoned out the black stuff and dipped the medusa
pieces in Seachem Reef Dip (mainly iodine) and put it back in
tank. Next day it was coming back so I tried another product from
local fish store (haven't seen it come back yet but its less
than 24hrs. Also done huge water change, added carbon and
Polyfilter. Local fish store thinks it is bacterial
and I should just
through it away incase it affects my Kenya trees. But after
growing it soo big I would like to salvage it as lots of small
pieces if possible Â if they survive I know they will
grow huge again.
My question is, should I restart adding the P04?
My thinking is that the RedSea bacteria may outcompete the strain
thatÂ¹s in there now? I am cautious because as the mix
of the two products seemed to have reacted badly but I've
also heard your not supposed to just stop the RedSea P04
Was this because the biopellets needed to be cycled in some way
<Not likely, no>
Although it does not say this in its instructions. I would still
like to use the biopellets in the future as its a more
natural/constant supply of bacteria that cannot be overdosed. The
reactor is presently running on an unoccupied tank.
<Smaller doses... what happened here can be described in an
operant universe as "something else became
rate-limiting", causing this crash. What you did in reaction
was excellent. Hopefully all will settle down in the near term...
I would dose, add some source of soluble phosphate and nitrate,
making sure there is measureable... for your chemoautotrophs. Bob
Lex of London
P.s. Sorry about large photos
Re: RedSea P04X + NP Biopellets = THE
Thanks for the response.
Just too let you know the second dip I done was with a product
called" coral rx pro " and it seems to have worked -
amazing. I will definitely use this stuff in the future to
pre-dip my corals.
<I see this product's ingredients listed as
I tried adding a quarter dose of RedSea p04x and got a small
bacteria bloom, so ill hold off on that for a while
Lex of London
<Bob of San Diego>