How To: Dosing 2 Part in Your Reef Tank

How To: Dosing 2 Part in Your Reef Tank

Today on BRSTV we are going to cover the complete
installation of a two part dosing system. Hi, Im ryan host of brs tv where each week
we cover a new topic related to reefing. This week we are going to go over the complete
installation of a two part dosing system. We will give a very brief overview of why
we dose these elements, discuss proper mixing of two part solutions, how to figure out your
tanks consumption, common pieces of equipment related to two part and finally answer a few
common questions. There is a pretty long list of reasons why
we want to maintain calcium and alkalinity but the primary one is corals and coralline
algae use these elements to produce their skeletal structure and grow. Second one is
maintaining a stable water chemistry and environment for all of the creatures in the tank. Wide
variations in alkalinity and pH make it difficult for a tank to really thrive. If you haven’t been maintaining calcium and
alkalinity properly before, using a system like this will absolutely result in a major
improvement in coral and coralline algae growth, stable water chemistry will certainly result
in health improvements for everything in the tank which will also be responsible for additional
growth and reduce losses. Mixing the solutions is probably the easiest
component. With the calcium solution just fill the jug two thirds full with filtered
water. Using a standard household measuring cup measure
out two and a half cups of calcium chloride and pour into the jug using the included funnel.
Then shake the jug until the solution is completely dissolved. The solution should dissolve crystal
clear. Then fill the rest of the jug up within a couple inches off the top. Label the jug
calcium and this portion is done. The alkalinity portion is a bit different.
While it is possible to dissolve the alkalinity portion directly in the jug it is much easier
to do it in an open top container where you can stir it while adding the salt. I am going
to use this empty container because it is also a gallon size but you could use a clean
bowl or bucket. Start by filling your jug 4/5’s the way full
with ro/di or distilled water and then pour into your open top container. Measure out
2 cups of sodium carbonate also known as soda ash. Using a spoon start stirring the water
slowly and pour in the alkalinity portion. All of the material should dissolve completely. Taking this extra step will help prevent the
clumps of soda ash that can form at the bottom if you pour the soda ash directly into the
jug. If you skipped this step and did get some of these clumps just float the jug in
some hot water and shake vigorously a few times throughout the day. Once dissolved use the funnel included in
the total package to pour the solution back into the jug and label alkalinity. Next top
the bottle off and give it a good shake. Time to mix the magnesium solution. Start
with eight cups of RO/DI or distilled water, three cups of magnesium sulfate and five cups
of magnesium chloride. There is a good deal of salt in there you are trying to dissolve
so there may be some crystals left in the bottom which should dissolve over the next
couple days if left in a warm location. You can avoid this by mixing it separately like
the alkalinity. Once again, top it off and give it a good shake. Label magnesium and
we’re done. Ok so all the solutions are mixed, we let
them sit for a few hours to dissolve completely and now it is time to discuss how to dose
the solutions to maintain proper calcium and alkalinity. There are two steps to this. First we are
going to assume your levels are already lower than you want them to be. Most reefers keep
their calcium at 420 parts per million. Alkalinity between seven and ten dKH , we suggest 9 dKH
as a good number and what most of us here at BRS maintain. Magnesium is most often maintained
at 1350 parts per million. To raise the tanks levels we are going to
use the reef calculator which is probably the easiest tool you have ever used. To show
you how this all works we are going to pretend we are just starting dosing this tank which
has around 70 gallons of water and a depleted calcium level of 390, a dKH of 6 and magnesium
level of 1200. We will start by entering the tanks water
volume which is 70 gallons in this case. To get the water volume I took the tank size
plus sump minus rock and sand. I might be off a bit with my guess of 70 but it is very
likely I am within 10% of the correct number. Don’t agonize over getting your guess perfect
because your test kit probably isn’t accurate enough to see the difference anyways. For
instance if I was trying to raise the levels 30 parts per million and I was off by 10%
and really added 33 parts per million it is very unlikely a hobby grade test kit would
be able to display the difference. Once I have the volume entered and the current
calcium level which is 390, my desired level of 420, and what I am are dosing with which
in this case is 2 part calcium solution and hit calculate. The calculator tells me I need
214 ml of calcium solution as well as some mixing and dosing notes on the side. One of the more important dosing notes is
a recommendation that I don’t change the calcium level more than 50 ppm in a single day. In
this case I am going from 390 to 420 which is only 30ppm so I can add it all in a single
dose. It also mentions that I add it slowly to a high flow area of the tank. My personal
preference is to pour it directly into a high flow powerhead which will disperse the solution
quickly and avoid small pockets where the calcium is temporarily really high. The calculator is really accurate so I can
come back an hour later, test and see that the levels are indeed 420 now. It is an incredibly
satisfying experience when something that was fairly confusing before is reduced to
something as simple as this. The alkalinity and magnesium components are
basically the same thing, enter my current levels, where I want them to be and it will
tell me exactly how much I need. When you are doing this make sure to pay close
attention to the alkalinity dosing notes. The alkalinity component will raise the pH
temporarily so we want to add it slower and preferably not more than 1.4 dKH a day. In
this case I am going from six to nine so I’m going to split the dose in half and dose over
the course of a couple days. In this case I would split up the recommended one hundred
and fifty millileters into four 38 milliliter doses.Keep in mind that the corals have consumed
some of the alkalinity in the last couple days so it isn’t uncommon to have to make
another small adjustment at the end. It’s also critical that the alkalinity solution
is added to slowly to a high flow area of the tank. The alkalinity solution will with
raise the pH. While the effect on this entire tank is pretty subtle. say from 8.1 to 8.2.
The effect on the localized area where you added the solution is obviously much higher.
For best dispersion I find adding it near a high flow powerhead, pouring it directly
into the overflow or dripping it slowly anywhere into the tank to be some of the best options. Ok we got the levels where you want them,
how do we keep them there? This is where the two part daily dosing comes in. Process is
pretty simple. More or less my corals and coralline algae have consumed some amount
of calcium and alkalinity in the last day since I got my levels right. We are going
to replace that small amount of missing calcium and alkalinity with the two part jugs we mixed
up earlier. To figure out how much our tank is consuming
we started with the recommended dose found in the instructions. Since it is pretty common
for most of reefers to assume more is better these are designed to be a starting point
and on the lighter side. So for instance on a tank like this one I would consider to be
medium to high demand tank demand since it has a somewhat dense mix of LPS and SPS . The
tank has around 70 gallons of water in it so we will start by dosing 20 milliliters
of calcium and alkalinity and then we’ll test in a few days. Turns out the levels dropped a bit so we upped
the dose to thirty to forty and then after a couple of more adjustments I found 60ml
a day to be the correct dose where the levels are stable. I’ll test again in a week to make
sure we got it right. I would like to note that it is much better
to start low and work higher rather than start high and work down because adding too much
can cause issues like precipitation which makes it harder to hone in on the right dose. So it really is that easy add a small amount
each day for a few days and test. It is pretty rare for it to take more than 3-5 adjustments
to hone in on the correct amount. Ok so onto what my daily dosing program will
look like. More or less I’m just going to add the same amount off calcium and alkalinity
every day. Same things apply here. Make sure to add it slowly to a high flow area of the
tank. Most people will do this at the same time as the feed the tank so isn’t that much
of a chore. The two part total package comes with a couple
dispensing pumps which can be used to dispense the solution into these easy to use measuring
cups. Just pump out what you need each day and pour into separate areas of the tank.
Make sure to use different cups or rinse between uses to prevent the two solutions from mixing
in the cup. The last step in all this is dosing the magnesium.
Magnesium isn’t consumed at the same rapid rate at which calcium and alkalinity is consumed.
However just as important because it is the presence of the magnesium which allows us
to maintain high levels of calcium and alkalinity in the first place. Magnesium levels are also
naturally much higher than the other two elements. Basically this means while you could dose
magnesium every day as well, it isn’t needed and most people don’t dose magnesium daily. All I need to do now with the magnesium is
once I have completely emptied both gallons of calcium and alkalinity with daily dosing,
is pour in 20 ounces or two and a half cups of magnesium solution. You can do this all
in one dose to a high flow area of the tank or in multiple smaller doses if you like but
this isn’t required. I won’t have to dose magnesium again until I completely empty another
pair of calcium and alkalinity jugs. Ok I have been doing this a long time now
with a wide variety of tanks and I’d like to make my life a bit easier with some related
equipment. Best way is by adding a couple of dosing pumps which add the correct amounts
automatically every day. The most popular solution for this is these small dosing pumps.
You will need two of them, one for each solution. Most people control them with an inexpensive
outlet timer or a timed outlet on their aquarium controller like the Apex or ReefKeeper. Basically
this pump doses at a known flow rate which in this case is 1.1 milliliters so getting
it to dose this tanks requirement of 60 milliliters I just need to set the timer to turn the pump
on for 54 minutes a day. I could also opt to make smaller multiple doses throughout
the day by having the timer turn on six times for nine minutes each. I can also elect to
do things dose the calcium during the day and alkalinity at night. There are also fancier dosers like this one
from Bubble magus which asks you the amount you want to dose and as well as the ability
to split the doses up automatically. For example selecting 100 millileters with one dose means
it would dose 100 milliliters all at once while 100 millileters with 10 doses means
it would dose 10 milliliters ten times a day split evenly over a 24 hour period. This one from Vertex does similar things but
with more adjustability using the sweet touch screen. They included the ability to dose
by day of the week, name each pump head, more flexible tools to adjust the volume of fluid
dosed. Japanese pump heads, and high quality motors including a stepper option for extreme
accuracy. There is also easy to use calibration option which is pretty sweet. Honestly this
touch screen makes it super easy to understand and operate, I think even the most technologically
inept of us could figure this out on their own without even looking at the directions. Because Vertex is Vertex they also make really
attractive containers for the three solutions just in case you decided a jug isn’t attractive
enough for your system. Honestly while this may seem silly to some of us, a lot of reefers
have just as much pride in their equipment room or sump area as they do the tank itself
so this is a solid option when form has to match function. For function alone we also stock these nice
space saving jugs which make it a lot easier to fit the jugs inside your cabinet of even
behind it. Bubble magus sells this nice screw on holder for the dosing lines so you can
control the area the solution enters the tank and make sure the dosing lines never get bumped
outside of the tank which could damage your stand, carpet or floor. If you are looking
for something a bit more polished and flexible vertex makes this nice magnetic line holder. Ok to wrap this all up we do have a couple
tips based on common questions we get. First off why is it called two part when there is
clearly three parts>Basically all the calcium and alkalinity dosing solutions are referred
to as two part even if they have a separate magnesium portion. The products that have
three parts are typically doing it because three part products allow you include elements
which match natural seawater ratios better. The true two parts skip one or more of these
elements so they can mix the calcium and magnesium solutions together. That brings us to another popular question,
can you mix the two parts together and dose just one solution? The answer is no, soon
as you mixed them they would instantly precipitate out and the solution would be useless. They
do have to be kept separate. Next the system is designed so you can use
equal amounts of calcium and alkalinity solution to make things easy. However there are a variety
of reasons why a small amount of people might find they need to use slightly more or less
of one solution than another. Don’t feel like the one to one ratio absolutely has to be
followed if your tank uses slightly more alkalinity than calcium solution just go with the flow. It is also pretty common for most people to
drastically reduce their testing after they get the tang of the system which is pretty
normal. If I was only going to test one element it would be alkalinity because it will drop
much faster than calcium. So it is fairly common for experienced reefers to test alkalinity
during normal maintenance cycles such as every other week when you do water changes and calcium
one a month or so. Once you have a stable two part system going it would be pretty unusual
for alkalinity to be spot on and calcium drift significantly. There is also a pretty sweet option for testing
alkalinity which literally takes less than 60 seconds. With the Hanna Checker all you
need to do is add 10 millileters of tank water. calibrate, add 1 millileter of reagent , invert
five times, replace the sample and hit the button. A few seconds later it tells you your
alkalinity. Lastly it is completely normal for the alkalinity
portion to cloud the water a bit when you add it, particularly when you pour it in by
hand. The tank should clear up pretty quickly. And you may find that your magnesium levels
are dropping even though you are adding the 20 oz of solution on time. This is almost
always because the salt mix you are using has low magnesium levels which is most of
them so every time you do a water change you are really reducing the levels. So that wraps
up today’s episode, if you have any questions or want to share your experience with two
part with everyone do so in the comments area below. If this is your first time with us
subscribe because we do this every week. Thank you for watching BRSTV.


  1. Trying to come up with a regimen that will help out with maintaining calcium and alkalinity. If I use the BRS 2 part system, do I still need to dose Kalkwasser (in order to maintain pH)? Or will the BRS 2 part system maintain my pH as well? Thanks!

  2. do you want to share some info about how to get red algae away?
    it is a horrible pest in my tank.
    all my 140 kg of live rock is infected 🙁

  3. great vid guys…
    i have a 65 gallon rimless…im using fusion 1 and 2….and aqua vitro balance…25ml of 1   and 25ml of 2 ,to my tank everyday.   should i change to the soda ash…and so on of the products used in the video…i have several sps…and lps   in my reef. 

  4. Which test kit were you using in this video? It had the syringe used for titration into the vial for color checking…

  5. I'm curious to why BRS doesn't mention the other two part mix with just plain sodium bicarbonate . I have had issues when dosing soda ash to keep levels up, no matter how small of a dose. My system was consuming a gallon of two part every five days via profilux and all levels were perfect as always but I was starting to have some SPS RTN STN on me and for weeks couldn't figure out why, so I switched to just plain bicarbonate and the tank went back to normal within a week no more RTN. Was just wondering why the other recipe is never mentioned anymore nor is it on BRS site? Is there something I'm missing? Thanks

  6. How much does this cost? Dou you ship to the uk? Also do you sell the Neptune apex DOS dosing pump (can't find this in the uk)!

  7. Hi Ryan, I have become a big fan of BRS videos. They have helped me make decisions and maintain my reef tank. I have a nano system, 29 gallon biocube. Has a refugium and is looking amazing, tons if corals all doing well. While I can keep all of my perimeters in check I seem to be losing alkalinity rather quickly. I have u a steady ph of 8.3 no ammonia and 0.25 nitrates. I have tried multiple products like kent marine alk buffer. But it seems that I need to add more than the recommended amount in order to keep my alk up to a 9.0. I've noticed I have to raise my alk slowly in order for my corals to respond well. My question is, is there anything else you can recommend trying in order to help maintain my alk levels? Side not, over feeding isn't an issue I feed fish every day just enough and use Red Sea reef energy for my corals. Thanks

  8. I've started your two part dosing program but have heard that this will slowly increase salinity levels in my aquarium.  What is the suggested remedy for this and how quickly does it occur?

  9. if my mag is low (below 900) 
    do i dose 100 per day to get it to 1300
    and how much will a gallon solution raise the mag level in about 75 gallons including sump

  10. This is probably obvious but on the alkalinity portion you said measure out 2 cups of sodium carbonate…then add the alkalinity portions are those the same?

  11. Always trust your product and appreciate your videos. Setting up a new tank. in my old tank i would run two part but would leave a small koralia nano pump to avoid settling of the two part while dosing (automatic pumps) Would you consider settling of the two part a concern if left standing for a couple weeks?

  12. So let's say I get the dosing parameters where they need to be.
    Once I do my water change I am taking out a bunch of water that has these doses already mixed in……So once you do the water change, you now have to add the doses back in to bring it up, right? just like salinity level………

    I have never done this before but I am getting ready to start dosing my tnak

  13. Hi, I'm thinking about getting my first saltwater tank, a 40 gallon tank with fish and sps corals. Is dosing something I will have to at any point or regularly?

  14. Hey Ryan. I am about to set up my first saltwater tank within the next couple of weeks…..all this dosing stuff looks like its going to be expensive!!Is it possible to avoid having to dose by doing more regular water changes?…if so, would this keep parameters to acceptable levels by just the added salt water mix. My tank is 195 litre and I will be using the Hydor Smart Level to top off with RO/DI….. with this in mind how soon after a water change would my Mg Alk and Ca be thrown out to unnacceptable levels. How often and what percentage water change would you recommend to avoid having to dose and could a tank thrive using this method…..and what types of coral would suit this best? Great channel by the way have been watching for over a year and its where I have gained most of my knowledge to attempt a salt setup!!

  15. I'm confused about something. Seeing how much you start out with per day and in the instructions it says .1ml per gallon witch is a very small amount. Is it really supposed to be 1ml per gallon. So is the decimal not supposed to be there?

  16. Hi Ryan, If you dose these in your tank is it still needed to dose Kalkwasser? Doesnt kalkwasser contain calcium also? Hope i dont sound to ignorant.

  17. Ryan- first i'd like to say thanks. I've learned much from you. I do have one problem though. I just got your 2=part dosing pumps. You say here you recommend allowing it to drip near the overflow? Do you still feel this way? I will have to run my tubing up over the top from the jugs below….

  18. Great video guys.. and you are doing a super job!! is there a way to also take care of the trace elements other than water changes?

  19. If you're using a doser, what's the best way to hook up the lines going into your tank, how and where? i.e. would you suggest soft lines going from the doser to a bit of rigid tubing held in place with a probe holder (or is there some other specially made holder?) over the powerhead?

  20. What can i do if my alkalinity is 11 and my calcium is 390??? I'm new to reefing and have two little fishies two part, help please! Can I just dose calcium?

  21. the pre mixed  2 part bottles  are the same as this only you don't have to mix?If not to high on the corals  you can dose every second day?on another note  how can ca be 430  dkh be 9   but ph is low at 7.8?.do I hv to raise the dkh?  but you have to dose both?

  22. Is it best to have your tank fully stocked with corals so that you don't have to readjust the dosing every time you want to add corals?

  23. so after I dose all the calcium and alkalinity you said two cups of magnesium, is this for any size tank? I have a 38 gallon one and I'm close to finishing my first two part mixes

  24. I'm currently dosing kalkwasser at night. I get the levels where I want them with 2 part but after a few days my pH, alkalinity and calcium all drop. Is there a max dose for kalkwasser? Should I also dose 2 part together with kalwasser?

  25. Just a note for everyone. Their alk calculator defaults to meq/l. Your test kit probably reads is dKh. Last night on my second day of dosing, this discrepancy caused me to dose 3x more than I was supposed to. Don't think I lost anything due to it, but alk did jump from 8.4 to 10.2.

  26. Hey there, i just want to say i love your videos. I've been in the hobby for about 2 years and i have learned a ton from watching so thanks for that. Since starting the hobby I've had a few different corals, all of which died over time. The only coral ive been able to maintain since the beginning is a bubble coral. Originally it had brown jelly which killed about 3/4 of it. However i was able to stop the spread and the bubble has since recovered to around the size of a baseball when fully inflated. But, its the only coral that thrives. Even a star polyp colony i have now is starting to die, and i know those are supposed to spread like wild fire under the right conditions. I've taken water samples to my local retailer for tests and they tell me my parameters are good. So i'm now convinced that my issue is due to not properly dosing, in fact i barley dose at all. I usually throw a cap full in when i remember every few weeks, This need to change ASAP as i want to start focusing on stocking my tank with more coral now that I've reached my limit for fish. I have a 65 gallon btw. So after watching many of you videos on dosing i'm trying to decide between the BRS 2 part system and the red sea coral package. Im sure both will give a drastic improvement with daily schedule. Where my confusion comes in is with the trace element aspect. I currently use instant ocean reef crystals with a 10% water change, usually every other week. What is your opinion on that salt? Does it contain the proper amount of trace element to where i don't need to dose them? There is so much to learn in this hobby and so many different opinions and methods, its very overwhelming. I like the BRS 2 part because it seems super easy to understand and put in to action, but the red sea comes all in one with the trace element dosing. Your guidance would be greatly appreciated. Thanks!

  27. What is alkalinity? Just alkali substances that make the pH higher? What is the difference between measuring alkalinity and measuring pH?

  28. started using bulk mix-yourself 2-part (Canadian, sorry BRS shipping is too much $! 🙁 ), is it common for the Calcium to get a sediment on the bottom? You guys are great!

  29. do i need dosing my aquarium.
    i mean i use calcium reactor in my tank so is it required doing dosing to my tank. As i am planning to build a 800+ gallon aquarium probably heavily populated with fishes and corals..

  30. kind of a stupid question but..
    if you start mixing the magnesium solution and forget how many cups you put in there because you got their anyway to test the actual solution to see if it's "correct"?

    thank you!

  31. what does it mean when my calcium stays high? I have a lot of sps corals in my tank. Right now my Alk. is 6.6 Cal. 577 and Mag. 1000

  32. Answered alot of my questions on the proper 2 part dosing method .. i suppose it helped by doing research beforehand and knowing the questions i needed answered .. really informative thanks ryan .. water change today then i can work on getting my dosing dialed in properly over the next week or two.

    Keep up the good work BRS .. p.s. we need brs australia ! Come on guys !

  33. Could somebody please help me?

    Am I correct in thinking that Calcium and KH are used up at the same rate?

    My current parameters are 8 dKh and 410 calcium, I'm stocked with very few LPS corals and no SPS corals. I do have some coralline starting to grow which I want to maintain calcium and KH to spread the coralline. However my problem seems to be that I'm losing about 0.2 dKh per day, my calcium only drops maybe 10ppm every 2 weeks or so. Meaning i'm having to dose for KH every day but not dosing for calcium at all. Why does my KH drop but my calcium doesn't? Thanks

  34. So i did all my mixes and been.slowly raising my alk and calc. having is my tank is using about 1dkh a day. But sometimes when i ad 7ml alk raises my alk by 1 dkh. Sometimes it doest… it seems like its always.different amounts…. what am i doing wrong??

  35. So I dose 2part Alk and Ca on a 1:1 ratio? I have been having an imbalance issue with my 2 part, using 2x more alk solution than calcium. Should I change this to follow the 1:1 to achieve ionic balance. Mg doesn't change. pH 8.2 consistently. 120g SPS dominant. Thanks

  36. great advice! I was so scared of manually dosing and killing all my fish and corals, Thank you BRS!!!

  37. if your on a budget and have colour deficiency vision is there a test kit that only involves really obvious colour changes that is also relatively cheap

  38. Confused on how he got the tank water volume.

    I have a 120g tank
    30g sump
    About 40lbs of rock
    And about 100lbs of sand

    So 120+30=150

    So I have total 10g of water in my tank?

  39. wow this is hard work . i didnt know keeping a reef would require me to be a chemist.. but ill learn. starting a salty tank in a few month

  40. Hi , love your presentations . I have one question is there a specific order one has to dose these 3 chemicals ..? ie mag cal, alk , or cal/mag/alk ? look forward to hearing from you

  41. Ok. My tanks water vol is 30 gallons, i have a Magnesium of 1180, prefer 1350. My BRS solution is all mixed up…tbe BRS calculator says add 13.9 fl oz. Can i dose all that at one time?? Wht do you recommend?

  42. Is it even necessary to test for magnesium since all that is needed is to add 20oz of magnesium after the 1 gallon jugs of calcium and alkalinity are empty?

  43. Hi. I just set up a new fish only tank of 250 gallons. Do we need to maintain calcium, alkalinity, and magnicium levels for fish only tank too. Moreover, what all the parameters need to be considered for fish only tank. If PH is more how to decrease it. N how to lower the nitrate level in the tank. Please answer my queries, it would be a great help. Thank you

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