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Q11084 - HOWTO: Additives: How and What to Dose by Daniel S., Reef Squad
When the uninitiated hear about saltwater aquarium care, their general reaction is "No way: saltwater tanks are too hard!"

The fact that you are reading this article means you either disagree or are willing to embrace the challenge in exchange for the joy of keeping some of the world's most fascinating and beautiful creatures.

The truth, that I hope you have learned, is that this hobby is not nearly as intimidating as it appears. In fact, the aquarium hobby can be relatively simple, or as complex as you care to make it.

The focus of most of our articles this year has been about ways to simplify the hobby, breaking it down into understandable segments to help you succeed. Our usual disclaimer applies: this article is meant for the average hobbyist, not prep work for graduate level biology study.

We may call it saltwater but, in reality, seawater is made up of numerous minerals, most of them only in trace amounts. Salt, as in sodium chloride, only makes up a portion of the molecular soup that is natural seawater. It would require a chemistry degree or some serious studying to truly understand the intricacy of what makes up the ocean's waters, but we're not going there. Instead, we're going to break down the subject of what to dose in your aquarium and how to do it.

There isn't one right way to be successful in the aquarium hobby. There are, in fact, many paths to keeping a happy, healthy aquarium. Today we will cover are a few basic ways to keep your water similar to what is found in nature. Your application may vary, but the principles shared here have worked for a great many hobbyists.

The most important way to dose your tank is to perform regular water changes. In addition to removing wastes, fresh saltwater also brings an influx of minerals that have been depleted back into the aquarium. This may not be enough on its own, but it is still the most important thing you can do to keep a healthy aquarium.

Now, before you pour anything into your tank, it is important to understand what you are adding and how much you need to add. You can easily throw off the parameters in your aquarium if you start indiscriminately adding things to your water. We commonly see this happening with alkalinity buffers.

New hobbyists, instructed to keep their pH at 8.4, repeatedly add buffer to their aquariums to maintain ideal pH. Instead, the alkalinity in the tank ends up skyrocketing, threatening the health of the entire system. The truth is, pH fluctuates throughout the day and is relatively safe between 7.9 and 8.4. Overdosing alkalinity and other additives can easily be avoided by simply testing first.

So, if the first step in dosing is to test, what should we test?

To keep things simple, I recommend at least testing for calcium and alkalinity. I strongly suggest magnesium as well. This is, of course, in addition to testing for water quality parameters like nitrate and pH. Test weekly and record the results in a tank journal or log. While not particularly fun, it is necessary if you want to see what effect dosing has on your system. A brand-new system may not need much calcium, but as it matures and corals grow, so will the demand.

After testing, you will know precisely where things are at. Now let's cover where they should be.

We recommend keeping calcium between 400-450 ppm (parts per million), alkalinity between 8-12 dkh and magnesium around 1300 ppm. While these ranges are acceptable, you should always shoot for stability in each of them. For instance, if your alkalinity is at 9 dkh, you should try to keep it there instead of dosing it up to 12 dkh and waiting until it falls to 8 dkh to dose again. Like most aspects of aquarium upkeep, keeping things stable is one of the keys to success.

It is important to note calcium, alkalinity and magnesium need to be in balance with each other. Without getting overly complex, knowing how to balance these will help you understand how much to dose.

Think of your water as an empty jar. Now, picture your calcium, alkalinity and magnesium as different colored marbles. Only so many marbles can fit inside the jar before they will go rolling over the sides. If you have all alkalinity marbles in your jar, then there is no room for calcium and magnesium marbles, and so on. If your alkalinity is testing very high and your calcium low, your calcium will stay low no matter how much you pour into your tank. In fact, if this happens, you may see it begin to "snow" while you are dosing. This happens because there is no room left in the water for the calcium. Always keep things in balance so that there is enough room for calcium, alkalinity and magnesium: 420 Ca, 9 Alk and 1325 Mag are good numbers to shoot for.

We now know where we're at and where we want to be. Let's talk about how we're going to get there.

The most popular method is to use a two-part dosing system, like ESV B-Ionic or Two Little Fishies C-Balance. The main ingredients are split into two bottles, calcium and alkalinity. Two-part systems are designed to dose all the important minerals in the same ratio they are used in your tank. For most aquariums, this is enough to keep things stable. The more frequently the system is dosed, the more stable conditions will be. It is better to dose small amounts daily than to dose large amounts infrequently.

You should get your parameters as close to the aforementioned numbers as possible when you first begin to dose your aquarium. Then, you can start adding small, equal amounts of part 1 and 2 to maintain the levels. Do not add parts 1 and 2 at the same time. You want the first to mix into the system before adding the second so that they do not react with each other and become unusable.

After a few days, test the calcium and alkalinity again. If they are below 420 ppm Ca and 9 dkh alk, then you will need to add a little more daily (after adding enough to get them back to where they should be). If the calcium and alkalinity are too high, hold off on dosing for a day or two instead. After a few weeks of dosing and testing, you will have gotten a feel for how much you need to dose daily and the task will become less tedious. Remember that as time passes, the aquarium will require more and more supplements to make up for the constantly growing corals and coralline algae.

Even though two-part additives do a very good job of keeping things stable, over time, magnesium and other trace elements may slowly fall. Aquarists with low magnesium often have difficulty with nuisance algae and falling calcium levels.

If you are having trouble maintaining calcium, it is very possible that your magnesium has fallen well below where it should be. I prefer to add a magnesium salt, like Seachem Reef Advantage Magnesium, to my top off water. A few spoonfuls in a 5-gallon jug of freshwater top-off do wonders for maintaining proper levels. I also see positive results by adding a few capfuls of trace element supplements every week or so.

Kalkwasser is an excellent alternative to two-part dosing. With kalkwasser dosing, you dissolve a small amount of kalkwasser (calcium hydroxide) into freshwater that is then slowly added into the aquarium via a drip or through an automatic top-off system. Kalkwasser also has the benefit of raising pH and removing phosphate. When adding kalkwasser through an auto top-off, a Kalkwasser reactor can be very helpful. The downside to kalkwasser: if added too quickly, it can dramatically raise your pH. That said, it doesn't need to be added daily to be effective.

Now that you've got the basics of water chemistry covered, let's delve into more advanced techniques.

Carbon source dosing may be right for you. Frequent dosing and a discerning eye are required, so proceed with caution. You basically add bacteria to your aquarium that eventually begins to overpopulate the tank. At this time a food source for the bacteria will then be added. The bacteria will feed on the tank's nitrate and phosphate resulting in a very clean aquarium environment. Now fattened on excess nutrients in the system, the bacteria become coral food or are removed by a protein skimmer.

Many hobbyists discover their systems have such a low nutrient load they must feed their fish and corals more heavily to keep them healthy. This, in turn, creates a strikingly beautiful aquarium, with stunning displays free of nuisance algae.

Three great systems for experimenting with this are Korallen Zucht's Zeo method, Brightwell's NeoZeo system, or Prodibio's Biokit. Each of these systems includes a bacteria source, a bacterial food and some form of amino acid or coral food. Follow the manufacturer's directions closely, as this is one area where you want to avoid overdosing. Don't hesitate to contact us if you have any questions.
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Approved Comments...
easy to follow Approved: 7/15/2014
Very helpful and easy to understand. Approved: 3/16/2014
Article was explained very well. As hobbyist you want to do whats best for your tank but also you cant just go Willy-Nilly and not know what the heck your doing especially when it comes to chemicals. The chart and the article were great articles and made me even more aware of how important it is if we want to be successful at this awesome hobby! Thanks Marine Depot for making it simple to understand. Approved: 6/30/2013
It is very educational for people who has no experience about saltwater reef. Approved: 4/29/2013
very infomative,easy to follow. Approved: 9/28/2012
Really liked the analogy of marbles in a jar. Approved: 9/4/2012
still learning about additives beyond water changes and purple up. Very helpful! Approved: 8/21/2012
Although Ive been doing this marine aquarium thing for years, dosing has always been a mystery, although Ive seen some of the stunning results in other systems from dosing. I appreciate the articles organized and logical flow as well as establishing the most important parameters. Thanks Much! Approved: 8/18/2012
Like always, Your articles are most beneficial to my job and general knowledge and being able to more intelligently converse with others. Thanks again, MD!! Timothy Approved: 8/9/2012
Thanks for sharing. Ive read this information in many books along with other articles, but you have summed it up in a one page easy to read article. Approved: 8/7/2012
Precise and very imformative wiyhout being overly technnical. I have a masters in science but often get overwhelmed with information. Nice to have a simple explanation of the basics. Thank u. Approved: 8/6/2012
easy to understand. Approved: 8/5/2012
People need to know That its not so hard Keeping salt water. Approved: 8/5/2012
Very easy to understand. Approved: 8/4/2012
I have been auto-dosing for about a year and still find I have to manually adjust the chemicals once in a while. I also use the Zeovit system and find that my aquarium is very healthy and the coral grows at a fast rate. Approved: 8/4/2012
love the marbles example- dumb it down for us amateurs! MORE MORE MORE Approved: 8/4/2012
Good and solid article until Carbon source dosing. Have no idea what this is about not even a brief into to what you are talking about here. Should not have even brought up the subject if you not going to talk about the subject. "basically add bacteria" what kind of bacteria? Approved: 8/3/2012
Good to have mag, alka, and cal handy Approved: 8/3/2012
very good, and simple!! I want MAS on this topic!! Maybe a followup article that goes a little more in depth!!! Thx MD Approved: 8/3/2012
I am new to Saltwater aquariums. This is so helpful Approved: 8/3/2012
It is just this simple to keep a salt water tank or salt water reef tank people listen to too many people with too many versions on how it should be done this the correct way if you follow this advice then you will not be a failure in this beautiful hobby amen. Approved: 8/3/2012
Excellent article! Precise, easy to understand, to the point. I cant tell you how many articles are written about this subject that Ive read that get so technical and wordy it leaves you more confused than ever! Thanks for making a seemingly complex subject easy to understand. :) Approved: 8/3/2012
short, simple, and to the point. i loved it, more like it please! Approved: 3/3/2012
Very clear and simple explanation. Approved: 2/18/2012
Thank you. More like this please. I would love to see more details on the other products you mentioned at the end of the article. When I looked the products up on your website the reviews said it all. But what combinations do I use? Hpw much? Can I use it with my auto top off? Any other tricks of the trade? Help me get to the next level of the hobby. Thats what its all about!!! Approved: 1/18/2012
i have a problem with hair algae.i started dosing with a bacterial additive called.marine sat its two weeks now,most of the hair alge is gone.i would like to start the neo zeo system by brightwell.your article was very helpful. Approved: 8/26/2010
Excellent information and nicely conveyed, a back to basics approach. Approved: 8/23/2010
keep them coming Approved: 8/22/2010
We mostly already figured all this out by ourselves over the past year. We now test every 3-4 days and mix our doses into our top-off water only changin dosing amounts weekly. All tests now have shown stability for over 6 months with all chemicals well within ranges you suggest. Approved: 8/22/2010
I have not read or heard much on magnesium as a magor mineral for reducing algae Approved: 8/22/2010
Very informative. Simple and easy to understand. To the point. Approved: 8/21/2010
insightful and easy reading for beginners Approved: 8/21/2010
Excellent information but this seems to be for aquarist with inverts more than strictly fish. I have a "killer" tank and would like more info on maintaining water quality for these fish. Approved: 8/21/2010
I really like the example of the jar of marbles. Really helped me visualize how Cal, Alk, and Mag work together. Approved: 8/21/2010
This is great stuff. I am a novice reef keeper, and find these email info-letters to be extremely helpful, often answering questions I am already wondering about. It helps me spend my money wisely, armed with the knowledge to do the right thing. Thanks very much, and please continue doing this! Approved: 8/21/2010
Simple and easy to follow, not overly technical. Gives me a better understanding of the 3 main components to sea water chemistry. In turn will help to get my system to where it should be. Approved: 8/21/2010
Good information without too much advertising. Approved: 8/21/2010
Easy to understand and right to the point. Approved: 8/21/2010
The first part was informative, but the second part about carbon source dosing was totally glossed over. I have never heard of this before, and after reading the article, I still have no clue what it is. Approved: 8/21/2010
Article Details
Created on 8/17/2010.
Last Modified on 9/27/2010.
Last Modified by Keith MacNeil.
Skill Level: Beginner.
Article has been viewed 30229 times.
Rated 9 out of 10 based on 132 votes.
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