Reef chemistry is a major part of this hobby and the basic reef water parameters (alkalinity, calcium, and magnesium) are better understood these days. Nutrition and basic nutrients in the water (nitrates and phosphates) required by the corals are also entering the discussion more. For advanced hobbyists, the next layer of the onion leads to amino acids and major/minor trace elements. Increased understanding of reef chemistry will improve your success in this hobby.
There are many off the shelf products that are currently available. That is clearly a viable option to the general to intermediate hobbyist. But for those who have large systems, are adventurous and more on the frugal side, and striving for deeper understanding could enter the realm of DIY Reef Chemistry. In various reef chemistry forums you can find recipes for DIY amino acids, nitrate, phosphate, and trace elements (strontium, manganese, iron, iodine, potassium, etc.). Those tend to be consumed the most in a reef aquarium. If your saltwater changes are not replenishing specific elements into your system you should consider supplementing.
Caution: Remember only dose what you can measure!!!
For example, I have a 7 tank – 510 gallon system that’s been up since 2006. I only perform small 3-5% water changes when I vacuum my substrate and detritus. One day I noticed my goniopora started shrinking and performed an ICP test. The results showed my system lacked manganese and iron. Based on current online discussions with other hobbyists, manganese is anecdotally linked to goniopora health. Due to the volume of water I have I decided to make my own manganese solution and calculator to determine the concentration and dosage needed to raise manganese back to an acceptable range. Once I started dosing manganese back into my system, the three goniopora started extending and plumping up again. From this personal experience, I have decided to strive to maintain a few of the highly consumed trace elements in range each time I perform an ICP test. I also make my own amino acids and nitrate supplements following the same process.
Due to the large volume dosed weekly, the cost benefits alone were a major motivator for me to pursue this path. In addition, some of the recipe concentrations can be catered to match commercial products if you want to follow a particular method or program. You will be shocked how little amount of material is actually used to make a 1 liter bottle of supplement. A little effort and education can reduce the long term maintenance cost of your system.
Some useful tools for the DIY Reef Chemist are the following:
- Proper test kits & ICP test Kits of your choice
- Digital Mini Scale up to 200g (0.01g resolution)
- Digital Food Scale up to 5Kg (0.1g resolution)
- Borosilicate Glass Beakers (50-1000 mL)
- Magnetic stirrer
- Adjustable / Calibrated pipette (1-10 mL)
- Measuring spoons
- Coffee filters (to strain out the filler materials if any)
- Non-Reactive storage containers
The general recipe would typically include the following:
- A base chemical source (purest possible based on Material Safety Data Sheet information)
- Amount of Reverse Osmosis water to mix with to create a desired concentration
- If needed, another compound to dissolve or act as a preservative
The recipes will typically include a ratio to mix and dissolve for a specific concentration. An equation to create a spreadsheet calculator would be used to determine how much to dose into the total tank volume to raise element x ppm or mg/L. These formulations found in various Reef Chemistry forums are provided by a few hobbyists who are professional chemists.
Refer to the allowable reef ranges defined for each element in you ICP results to understand how far off you are to get back within range. Most times some is better than nothing so it may not be necessary to achieve perfection.
As with the basic elements for alkalinity, calcium, and magnesium never dose the whole amount at once. Always spread the total dosage over multiple days and watch how your livestock respond and do not continue if you think you see side effects. It is very important to take a mental snapshot of your system when it is in peak health so it will be easier to notice when things start to go downhill. Daily observation is a simple but beneficial activity in this hobby.
Once you have your solutions, perform the required tests to understand your systems weekly consumption and dose appropriately to maintain. This may need to be done regularly over time since the consumption will change based on your bioload and water change schedule.
1 mL of Reverse Osmosis water = 1 gram = 1 cc
1mL of 1.026 S.G. / 35 ppt Saltwater = 1.026 grams
1 ppm = 1 mg/L