Category Archives: Chemistry

Dosing Supplements.

Many new people to the hobby read about how to dose supplements and want to start dosing their tanks as they feel they may not be completing something that is required for a healthy and stable set-up. Or maybe they do not even not completely understanding why/if we need to dose supplements to begin with, just as I did (or did not) when I started out in the hobby.  The truth of the matter is, whether or not you will need to dose will depend completely on the specific requirements of your set-up.  The ultimate goal of dosing is to replace the elements within your water that will get used up by your set-up and to maintain stable water parameters like that which are found around the coral reefs in the ocean (where most of the fish and corals that we keep come from).  Before going any further, I would suggest reading the below article which contains many suggestions for what basic levels you should aim for to maintain a healthy set-up.


The first step to determining if you need to dose supplements or not, would be to ensure you have a good maintenance routine in place along with a good and disciplined water change schedule. Most people have very good results with 10% weekly water changes.  Removing old water from your set-up and replacing it with freshly made salt water will also replace at least some of the used elements along with used trace elements in your aquarium.  In FOWLR and very low demanding mixed reef set-ups, most hobbyists may never need to dose any supplements at all as their water changes will provide the needed supplements to replenish what was used.  Corals, invertebrates with hard shells, and different types of algaes will all use different elements in the aquarium water. In my experience, testing your alkalinity, calcium, and magnesium levels weekly with a good quality test kit will allow you to determine when these more common elements are becoming depleted and let you know when/if you will need to dose anything at all.  Once any of these three levels start dropping, even with a good a disciplined water change schedule, you will need to consider dosing.


In most set-ups, the first parameter that will typically start to become depleted is your alkalinity.  At the least, this has been my experience. There are many good supplements out there as options to use to bring your alkalinity levels back up.  At first, I would strongly recommend using a commercially sold aquarium alkalinity supplement that you can purchase at a local fish store or from on line vendors.  I would not recommend making your own supplements until you have more experience using readymade ones.  When it comes to dosing, I would caution you about using the recommended dosing amounts that are listed within the instructions for use on the bottle.  These listed amounts are only to be used as guidelines as everyone’s set-up will have different demands.  I have had great success in the past by starting with ¼ of the recommend dosing amount, only using that as a starting point to determine my actual daily dosing amount.   As a example, in the first marine tank that I had set-up, my alkalinity levels had dropped from 9.6 to 8.2 in 3 or 4 weeks. This started to happen a few weeks after the aquarium matured and I started adding more corals and fish. It was at that point that I wanted to start dosing to not only bring that level back up to 9.6 (which is the alkalinity level of the salt that I like to use) but to keep this parameter stable. The instructions on the alkalinity supplement that I chose to use suggested dosing 10 ml every second daily.  I used ¼ of that amount and started dosing 1.25 ml every day (1/4 of the 10 ml is 2.5ml every second day, which means 1.25 ml each day).  After two weeks of dosing at this level, the alkalinity only increased to 8.4.  I doubled the dose to ½ of the recommended amount and started dosing 2.5ml every day for the next two weeks.  This amount kept my alkalinity levels stable at 8.8 to 9.0.  It took another ¼ dose increase to get it back to between 9.4 and 9.6. You will have to keep in mind that when you start dosing, you also want to make the changes in your parameters slowly over time (days or weeks). 


For set-ups with sumps, it would be best to add your supplements in the last compartment (return pump compartment) of your sump to allow the additives to become mixed in with your tank water as it makes it way up to the display tank.  In set-ups without a sump, it would be best to take a container of tank water and add your additives to this water so you can slowly add it to your set-up as you pour this water back into your tank. Once/if you get to the point of having to dose for more than one element, the timing of adding these supplements to your aquarium will be important as you do not want any two supplements to mix together before they can become fully diluted into the water.  I prefer to dose my alkalinity early in the morning and then my calcium late in the evening to make sure I can avoid any potential problems from theses additives mixing together in their concentrated form.


One good option to help simplify daily dosing is to use a automated dosing pump.  After a few years of manual dosing by hand, I had got a automated dosing pump.  I just program in the time of day I want each pump with to come one and the amount I want each pump to put in the set-up.  Each pump draws a dosing supplement from its own container and pumps supplement into my sump.  It certainly can make dosing supplements a lot easier as you do not have to remember (or forget) anything.   If you can fit one into your budget and your set-up, they will certainly make things a lot more easier for you.  I now only check to make sure the containers hooked up to the dosing pump are full and the dosing pump is still working.


Another good option is  a calcium reactor.  As I have yet to use a calcium reactor, I would refer you to the below article for more information.


Always remember that when it comes to dosing supplements, the best approach is to always: keep it simple, stick to the basics (dKH, Cal, & Mag), and never dose anything you can’t test for.  In order help you keep it simple, I have listed below, what I would suggest as the best approach for elements to test for and potentially dose for to maintain your target levels and help you have a healthy and stable set-up.  I had great success by only focusing on the top three parameters in my last reef tank with mostly SPS corals.

 The below recommendations are from a article on Reefkeeping magazine.  I have always had very good luck focusing on the basics elements (listed below).

A) Critical elements to test for and the most common to find requiring at least some dosing.  These are what I often refer to as the basic elements to focus on.
B) Potentially useful elements to test or dose for in more advanced or set-ups with special requirements
-Iron (required in most set-ups with large quantities of macro algaes)
-Silicates (required for a wide range of sponges if kept in large enough quantities)

C)Elements potentially not required to test or dose  for in aquariums with very few exceptions
-Certain amino & fatty acids


The below link will take you to article that I quoted above.


Common Approaches to Filtration in Marine Aquariums

You have a few different options when it comes to providing proper filtration for your marine aquarium.  The below are the common approaches to filtration in marine aquariums that I have used as well as some pros and cons.

There are three categories of filtration that you need to look at, biological, chemical, and mechanical filtration.  Each has a slightly different purpose in your aquarium.

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The Basics of Marine Aquarium Water Parameters

When many people are considering setting up there first marine aquarium, they can develop a perception that water chemistry (parameters) in a salt water environment is a complex topic. In my experience, this is just not the truth. While you can take this topic to a level of highly in-depth analysis and complexity, in practically every situation you will run into you can have very great success by applying a good understanding of the basics. I would like to share with you how I have learned the basics of marine aquarium water parameters. By taking this approach, the water chemistry (parameters) are not all that complicated at all.

Ammonia and Nitrites:

Ammonia and nitrites are byproducts of the nitrogen cycle at work in your aquarium. Once your aquarium is cycled, these parameters should undetectable by your test kits. Having ammonia and/or nitrite in your tank can be harmful to almost all forms of marine life. This is very similar to any fresh water aquarium. For a little more detail about the nitrogen cycle and/or cycling a marine tank, please check out the below links

Nitrates and Phosphates:

Based on what I have read, the nitrate and phosphate levels found in the ocean can vary a lot, but can be found in levels as low as 0.003ppm in most of the coral reef were we find the corals and fish that are commonly kept in the hobby. Maintaining those levels for nitrates and phosphates in an aquarium can certainly be a challenge at times, but not very difficult to do with a correctly planned and maintained set-up. I have always preferred to maintain my phosphate levels at an undetectable level by my test kit and my nitrates at the same. In the past, the nitrate level in my tank spiked at 2ppm while the tank was maturing and I was still making adjustments in my routines. Based on my experiences, the below are among the more common causes to higher levels of nitrates and phosphates:

A) Insufficient growth of nitrate eating bacteria. One of the biggest differences in the nitrogen cycle in a marine set-up when compared to a fresh water set-up is that a marine set-up with live rock will grow bacteria that will consume your nitrates and convert it into nitrogen gas. The best and most efficient way to grow enough of these bacteria is to have a good amount of live rock in your aquarium to provide a natural environment for the bacteria to grow. With enough live rock in your set-up, your nitrates should not get very high at all provide all other elements of your set-up are very well maintained. This is one of the many reasons why I always recommend the use of rock in an aquarium. The below link explains a few more benefits to having live rock in your aquarium.

B) Live rock adding nitrate and/or phosphates into your water. Live rock can be like a sponge and when exposed to higher levels of nitrates and/or phosphates in the water, absorbing these elements into the rock through the pours of the rock. This is very similar to osmosis. When the rock is later in tank water with lower levels of nitrates and/or phosphates than before, the rock starts to release nitrates and phosphates back into the water to restore balance between the nitrates and/or phosphate in the rock and in the water. The best way to avoid this is to cure your live rock before using it in a aquarium. The below link will explain how to cure you rock before adding it to you set-up.

C) Over feeding adding nitrates and phosphates into the water. This can be one of the easiest problems to create for yourself, as well as one of the easiest ones to fix. Most fish foods along with the resulting fish waste, will contain both nitrates and phosphates which will affect your water parameters.

D) In efficient routine maintenance, mostly not enough water changes. You need to take a little different approach to weekly water chances on a marine tank as compared to a fresh water aquarium. Typically, most people have great success with 10% weekly water changes, however, some hobbyist have had great success with 25% biweekly water changes while other do around 5% in a effort to reduce the nitrate and/or phosphate levels in the set-up. Each set-up has different requirements so you need to find what works for your aquarium.

E) Inadequate methods to consume/remove the nitrates and phosphates. By this I am referring to methods other than waterchanges. These methods include things like: having a properly sized protein skimmer on your set-up, using chemical filter media which can remove nitrates and phosphates from the water, and using a algae scrubber to name a few of them. I have always had great results using a good quality skimmer rated for more than the actual size of my set-up, growing macro algae in a sump, and using a algae scrubber. Carbon dosing is also a option but this should be left with hobbyist that have a little more experience in order to be able to manage the risks of carbon dosing. The below links can help ad a little more detail.


I am still amazed at how many people in the hobby today under estimate the importance of maintaining their salinity at or near 1.026, which is the average specific gravity of the ocean at the temperature and depth were we find most of the corals and fish that we keep in the hobby. The lower your salinity is from 1.026, the more you will risk having challenges maintaining other aspects of water parameters. I always prefer my salinity to be between 1.025 and 1.026. This is about 35.5 PPT (parts per thousand) for those of you who prefer using that scale/method to measure salinity. It would also be important to note that it would be well worth the expense to get yourself a good quality refactormeter to test your salinity and get accurate readings. I have found the hydrometers with the little plastic swing arms inside can (at times) be off as much as 0.003. You should avoid using one.

Alkalinity (dKH), Calcium (Cal), and Magnesium (Mag)

The alkalinity (dKH) refers to the measurement of carbonate hardness, while the calcium (Cal) and magnesium (Mag) are referring the concentration (in parts per million) of these elements in the water. This is one topic that has been found to be key to having a long term healthy reef tank and one aspect of water parameters that many hobbyist spend the majority of their efforts on. Based on the work of Randy Holmes-Farley, the below list shows what he has found to be a good balance which will help to keep the rest of your water parameters stable. I have found that I have really good success when I maintain my dKH and Cal balanced within Randy’s scale. You can find a lot more detailed information about Randy Holmes-Farley’ work at Reef Keeping Magazine (on-line magazine). I found it the easiest to keep my calcium level of 420 to 430 by keeping my alkalinity at about 9.0 to 9.6 dKH. I have also found the dKH and Cal levels will be a lot easier to maintain if you keep your Mag levels between 1280 ppm (the level of natural sea water) and 1350 ppm.

370 ppm to 1.4 dKH
380 ppm to 2.8 dKH
390 ppm to 4.2 dKH
400 ppm to 5.6 dKH
410 ppm to 7 dKH (natural seawater)
420 ppm to 8.4 dKH
430 ppm to 9.8 dKH
440 ppm to 11.2 dKH
450 ppm to 12.6 dKH
460 ppm to 14 dKH.

It is generally accepted (rule of thumb) that dKH levels between 6.5 to 7.0 and 12 with your Cal levels between 350 and 450 are considered safe. When either of those two levels ends up outside of those mentioned safe ranges, there will be some risk. Depending how far out of that range they actually are, it will mostly likely have a strong effect on your other parameters and can lead to a more serious situation. It is also interesting to note that at anytime your dKH and Mag levels drop to the lower limits within the normal/safe ranges, nuisance algaes can start to take hold.


Once you have your: salinity, dKH, Cal, and Mag somewhat balanced and stable, your pH will typically stabilize between 8.0 and 8.4 which also very close to the natural range of pH you will find in different areas of the ocean. As long as yours is within the 8.0 to 8.4 range and it is stable, you will run into very few difficulties, if any at all. The below link also has some more information on pH in a marine aquarium and has some other helpful information should you run into difficulties keeping your pH stable. Another factor that can affect your pH is the quality of the water you use to mix your salt with, and the quality of your salt. I found that using reverse osmosis water with 0 TDS(total dissolved solids) and a good quality salt will really help you keep your pH stable, almost as much as the above mentioned factors.


Many hobbyist seem to have a personal preference based on the requirements of either fish or corals they keep. The key is to have a stable temperature anywhere between 77F and 81F. I prefer to keep my temp between 78F and 79F.

The below chart summarizes how I approach the water parameters in my marine aquariums. It’s a very very similar approach that most people have for their fresh water aquariums with the addition of dKH, Cal and Mag levels. As you can see, there are only 4 additional elements to test for when compared to a typical freshwater se-up.

There are a lot of other aspects of marine water parameters that you can add to the above list. In my experience with the corals and fish in my set-ups, if I do a good job of maintaining those above listed parameters and remain disciplined with my weekly 10% water changes using a high quality salt with RO water, I do not have to worry about testing and maintaining anything more than this above list.

Dosing Supplements

So… Should you dose supplements to bring your parameters within the preferred range ? I have been asked many times by people new to the hobby if they should be dosing supplements. Whither or not you dose will all depend on your test results for your dKH, Cal and Mag. In my experience, lower levels of dKH, Cal, and Mag are a result of having a set-up with: higher demanding corals with classified skeletons, lots of coralline algae growth, or a combination of both.

Some low demanding systems with few (if any) corals and a disciplined weekly water changes schedule of ~10% or more, may not require any supplements to be dosed at all. This is due to the water changes replacing the used elements and maintaining your parameters which better quality salt mixes can provide you with. Aquariums with a moderate or heavy stocking of corals will typically consume a lot more of these elements out of the water than waterchanges can replace.

For those of us who keep reef tanks, these parameters are even more important to keep a close eye on as corals and coralline algae will consume more and more of these elements out of the water as they grow potentially causing changes in the water parameters. The first to be typically effected is the dKH, followed by the Cal and the last is Mag. Once/if the levels get outside of the safe range or become un-balanced with each other (even with your weekly water changes), you will need to start dosing supplements to replace the dKH and Cal which are being consumed by your corals and coralline algae. When dosing supplements you have to remember to take it slow. I would recommend getting a good quality supplement for each element (dKH, Cal, and Mag). Start by dosing at 1/8th of the recommended dosing amount while following all other of the manufacturer’s instructions printed on the bottle. After a day or two, test your parameters again and adjust your dosing amount from there. Just make sure if you are dosing all three elements on the same day, that you do not added all three at the same time. Dose only one element allowing enough time for it to become completely mixed in the water before adding the next one.

A calcium reactor can also be utilized to help maintain these three parameters. More information on calcium reactors can be found on the below link. I would not suggest people who are newer to the hobby getting and setting up a calcium reactor until you have completed a lot of research on the safe use of one.

I prefer to either manually add the supplements to the water or to use an automatic dosing pump to add the supplements to the water. I prefer the below dosing pump.

What are good parameters for a FOWLR set-up ?

I have a different opinion of this than most other people do. You can find all kinds of information out there where people will state a different set of water parameters for fish only aquariums as fish are typically more tolerant to swings in certain parameters as compared to most corals. While this certainly is true, I am of the opinion that there is only one standard to aim for in a marine aquarium for many different reasons, some of them are described below.

A) Most of the fish we keep in fish only set-ups as well as reef aquariums come from or near the coral reefs in the ocean. While they can tolerate water parameters outside of the corals reefs, they will be a lot better off and have better long term health when kept in similar and stable parameters just as the coral reefs they are naturally found in. Fish always to better the closer we can maintain our water parameters that which we find in their natural environment (the ocean).

B) Maintaining parameters outside of the above mentioned parameters can lead to other potential problems such as a wide range of different nuisance algaes

C) Your goal should be to aim for the optimal, not the minimal. I can best make this point by using an analogy. In our modern day society, our prison systems have shown us that a human being can live out most of their natural lives in a 8’ X 8’ room, provided all other basic needs are met. Yet, when you go to find a new place for yourself to live, you don’t pick a 8’ X 8’ room. You pick a place that you can comfortably live in for many different reasons, living conditions being just one of many potential factors that you balance when making that decision. You need to take this same approach when maintaining your water parameters.

And just as a point of reference, the below chart shows the three common ways to measure alkalinity and how the values of each measurement cross reference to each other. I thought I would post this chart here as well just in case we have any readers who are used to measuring alkalinity differently than the way I am most comfortable with.

If you have any questions about anything else in this article, feel free to go to our forum and post your question using the below link. If you are not already a member, it will only take seconds to sign up.


Tap Water or RO Water, What’s the Big Deal ???

As most people have already learned, the key to any type of successful marine aquarium is to obtain the best water parameters possible and to keep these parameters stable. When referring to marine aquariums, I am speaking of both reef and FOWLR (Fish Only With Live Rock) style aquariums.  The reason being is that most of the marine fish that we keep are wild caught and come from (or near) a coral reef and therefore would need the same water parameters as a reef tank if they are to thrive and remain healthy over the long term.


Just like the key to cooking a good tasting meal is to use the good quality ingredients, the key to maintaining good water quality in your marine aquarium starts by using good quality water.
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What are the benefits of live rock

When it comes to marine aquariums, you have a few choices for filtration.  I prefer to use live rock for many different reasons.  I have been asked many times why I prefer live rock over other types of filtration, so I thought I would take some time list the pros and cons of using live rock to help other decide if they would like to us live rock in their aquarium.

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Carbon Dosing in Layman’s Terms

Carbon dosing certainly is not a new concept, but it has become more popular in recent years as hobbyist have been learning more about it and seeing some good results.  It can be argued that this topic must be researched just as you would any other aspect of the hobby, but I would suggest this would require a little more detailed research as carbon dosing requires a good understand of: maintaining good water chemistry (water parameters), the factors that affect water chemistry, and how to quickly recognize changes in the appearance of your corals and/or the behavior of your fish.  I would even go as far as to suggest using this article to guide your further research into this topic before deciding to start carbon dosing.

In addition, if your only goal for carbon dosing is to reduce very high levels nitrates and phosphates, then I would suggest carbon dosing may not be for you.  In this instance, carbon dosing is only addressing the symptoms of high levels of nitrates and phosphates and not the causes of them.  You could still have a problem with your set-up that is just not noticeable now and possible has even been complicated even more.  After all, your very high nitrates and phosphates were not caused by a lack of carbon dosing.

I’ll try to explain what I have learned about carbon dosing and share some of my experiences with it.  I prefer to explain things in layman’s terms as much as possible as I usually just give myself a headache when I try to correctly spell all of the scientific terms or all of the different scientific names of all the different types of bacteria.


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pH in Marine Aquariums

pH (Potential Hydrogen) is simply a way to measure the concentration of hydrogen ions in solution. With a PH of 7.0, water is said to be neutral, anything lower becomes acidic while anything higher is said to become alkaline (basic). The scale used to measure pH is also logarithmic due to the enormous range of hydrogen ions. Using this type of scale, you will see a increase in hydrogen ions by a factor of 10 for each 1.0 difference in the pH values. For example, when you have a PH of 6 there is 10 times as many hydrogen ions as compared to a pH of 7 and 100 times as many ions as compared to a pH of 8.0. This is a good way to illustrate the potential scope of the impact a change in pH can have.

Generally, a pH of 7.9 to 8.4 is considered to be the normal range for a average marine aquarium. I always like to keep my pH stable at a value between 8.0 and 8.3. pH is a very important element of water chemistry to understand and test for, as large and quick swings in your pH can cause stress to fish and corals even resulting in deaths in certain situations. pH is one of the aspects of water quality that can also be an indicator or symptom that something else may be off in your set-up. For that reason I do not recommended trying to adjust your pH with pH stabilizing or adjusting chemicals as you may not be fixing the potential problem(s) but only masking the symptoms. If you are having difficulty maintaining your pH, you should first try to understand the cause of the pH problems and address those causes first. That approach has always worked best for me.

The two biggest factors that commonly affect your pH are:

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