It is easy to deplete your system of these important elements and if they don’t get replaced somehow, your coral’s health will suffer.
Dosing these elements back into the aquarium as they get used up naturally, will prevent fluctuations and depletion of these elements.
In this article, we will review reef tank dosing and proper methods for adding supplements to your saltwater tank.
Methods to dosing a reef tank
Basically, you have 2 choices when dosing a reef tank.
- Manual dosing
Both methods will work and many people rely on manual dosing either on a schedule or perhaps when they remember to do it. But that’s where the problem comes in with manual dosing. It’s not as accurate, effective, and reliable as automation.
Most people will start with manual dosing then realize how much of a hassle it can be, then quickly switch over to using an automatic dosing unit.
With automation being so good and with many options available, it is the smarter way to dose. After you check your water levels for Ca, Mg, Alk, you can set a precise amount of supplement to be added to your tank on a constant schedule. This not only is effective and convenient but also keeps the levels constant. As these elements get used up, they are being replaced at a specific rate and amount that you set specifically for your tank.
Do I need to dose a reef tank?
Also, there are other things besides corals that will cause the depletion of the big 3. Coralline algae, snail shells, microfauna, microflora all use it. Have you ever noticed the calcium build-up that can appear on your equipment, hoses, etc..? This also uses up calcium. So, unfortunately, yes you will need to dose a reef tank.
Can you maintain proper levels with regular water changes?
No, you can’t. Let me explain.
Let’s say as an example, you mix a fresh batch of saltwater for a water change and the magnesium tests at 1250ppm. Over a period of a week, you test your magnesium level, and let’s say your tank uses up 100ppm of magnesium.
If you plan to do a 10% water change every week, this will top up much of the 100ppm magnesium you lost but not all. The following week you plan to do another water change but will be starting that week with less than the 1250ppm magnesium you want, maybe it’s 1200.
So another 100ppm is used up that week, you do a 10% water change again and it raises the magnesium a bit. But again not the same amount that was depleted. So over time, you will never be able to replace the amount depleted and this element will be greatly reduced from your tank.
It will deplete more than you can replace with water changes only.
Why is it important to maintain these parameters?
As mentioned, maintaining a constant level of calcium, magnesium, and alkalinity is important to your coral’s health. The ocean is a huge place and the amounts of the big 3 will vary depending on location.
If you look at the size of a reef, it only makes up a tiny portion of the sea, and these parameters spread out over reefs will be very consistent. Calcium, magnesium, and alkalinity levels don’t shift much on natural reefs.
Any live organisms from the reef have a constant supply of the big 3 which they need to thrive and grow. If moved to an aquarium where there are fluctuating parameters, these organisms will not thrive and grow at all. Chances are they will lose color, become deformed, and eventually die.
What should these parameters be?
There is a relationship between calcium, magnesium, and alkalinity. For example, if your magnesium gets too low, the calcium and alkalinity won’t be able to hold constant. Remember consistency is the key to success.
All tanks will have different needs and no 2 tanks will be exactly the same. But you should aim to maintain the following parameters.
Alk 8.5 dkh (8-12 dkh range) Try and keep this in balance with calcium. For example, if you end up using the lower end of this scale then you should aim for the lower end range of calcium.
Magnesium 1300 ppm (1250-1450 ppm range)
Calcium 440 ppm (380-470 ppm range) remember to keep in balance to alkalinity.
How does automatic reef tank dosing work?
Setting up a dosing system can be done quite easily. If you want to dose calcium, magnesium, and alkalinity, you will need 3 containers to hold the liquid that will raise the big 3. You can use any suitable jugs or plastic containers, but I recommend you use specific dosing containers.
Have a piece of tubing that runs from each of these containers into a pump on a doser. A doser is simply designed to pump a very precise flow rate of a solution into your tank or sump. A dosing pump uses a Peristaltic pump system and will deliver this precise flow rate of a solution by drawing a measured amount into a chamber and then injecting this volume of solution into the tank being dosed.
At set times throughout the day, the doser pumps a set volume of the solution from each container into the tank.
Dosing pumps and price
Just because you are using automation, it doesn’t mean that it will be expensive. Most things in the saltwater aquarium hobby can fit your needs within your budget. With dosing pumps, there are very affordable options and more expensive options depending on the brand and features you want.
A typical 3 pump doser for calcium, magnesium, and alkalinity will cost around $250-300. The Bubble Magus T01 is good quality and reliable dosing pump. There are cheaper options available, but I recommend you stay away from the cheap units as something as important as dosing, you need to be very reliable and accurate.
If you want to spend a bit more money for extra bells and whistles, expect to spend around $375-400. The Kamoer F4 Pro is a great dosing pump. The extra cost will get you an additional pump for a total of 4, and includes WIFI.
Setting up your dosing pump
As mentioned above, setting up your dosing pump is quite simple. It’s a good idea to keep the doser and containers under your tank within the stand and have it flow into your sump. Some sump tanks will have integrated tube holders to make connecting the hoses very easy to do.
From your dosing container, run a piece of tubing to one side of the pump. Then run tubing from the other side of the same pump into your sump or straight into your tank.
It’s important to note that the tubing needs to hang above the water level of your tank/sump to stop back siphoning. You may want to put a shelf within your stand to rest the dosing pump on. This keeps things looking neat and tidy in the stand and keeps the pump secure and level.
Once your dosing pump, containers, and tubing are in place, you can add your solution to the containers.
Determine how much solution you will need
In order to determine how much solution to dose into your tank, you can use an online calculator which is very helpful. You can use the Marine Depot online reef calculator. You will need to measure your current levels before using the calculator.
- Calcium – Using the calcium reef calculator, simply enter the total system volume of water you have in your tank. Then enter your current calcium reading and your desired level to maintain. Select the product type of calcium you plan to use, and the calculator will show you the exact amount you need to dose.
Total system volume: 120 gallons
Current calcium level: 400ppm
Desired calcium level: 450ppm
Product used: AquaMaxx Synergy Plus (part A)
Result: 375ml is required to bring the calcium level up to 450ppm.
You can now set your dosing pump to deliver 375ml of calcium supplement to your tank. It’s important to set this to dose over a period of time and not all at once. A few days should be sufficient. In order to maintain your desired level of 450ppm, you will need to dose a certain amount each day. Let’s say your tank uses up 10ppm per day. It will take 5 days to go from 450ppm to 400ppm.
If you need to dose 375ml to bring the calcium level back to 450ppm, over a 5 day period that is 75ml per day. Set your dosing pump to deliver 75ml per day to maintain a desired level of 450ppm. This will maintain a constant level of calcium without fluctuations.
You can find The Aquamaxx liquid calcium supplement here.
- Magnesium – Using the magnesium reef calculator simply enter the total system volume of water you have in your tank. Then enter your current magnesium reading and your desired level to maintain. Select the product type of magnesium you plan to use, and the calculator will show you the exact amount you need to dose.
Total system volume: 120 gallons
Current magnesium level: 1200ppm
Desired magnesium level: 1300ppm
Product used: Brightwell Magnesion (100,000ppm)
Result: 461ml is required to bring the magnesium level up to 1300ppm.
You can now set your dosing pump to deliver 461ml of magnesium supplement to your tank. It’s important to set this to dose over a period of time and not all at once. A few days should be sufficient. In order to maintain your desired level of 1300ppm, you will need to dose a certain amount each day. Let’s say your tank uses up 20ppm per day. It will take 5 days to go from 1300ppm to 1200ppm.
If you need to dose 461ml to bring the magnesium level back to 1300ppm, over a 5 day period that is 92ml per day. Set your dosing pump to deliver 92ml per day to maintain the desired level of 1300ppm. This will maintain a constant level of magnesium without fluctuations.
You can find the Brightwell Aquatics Magnesion supplement here.
- Alkalinity – Using the alkalinity reef calculator simply enter the total system volume of water you have in your tank. Then enter your current alkalinity reading and your desired level to maintain. Select the product type you plan to use, and the calculator will show you the exact amount you need to dose.
Total system volume: 120 gallons
Current alkalinity level: 8.0 dkh
Desired alkalinity level: 10.0 dkh
Product used: AquaMaxx Synergy Plus (Part B)
Result: 107ml is required to bring the alkalinity level up to 10.0 dkh.
You can now set your dosing pump to deliver 107ml of alkalinity supplement to your tank. It’s important to set this to dose over a period of time and not all at once. A few days should be sufficient. In order to maintain your desired level of 10.0 dkh, you will need to dose a certain amount each day. Let’s say your tank goes from 10.0 dkh to 8.0 dkh over 5 days and uses up 107 ml of solution.
If you need to dose 107ml to bring the alkalinity level back to 10.0 dkh, over a 5 day period that is 21ml per day. Set your dosing pump to deliver 21ml per day to maintain the desired level of 10.0 dkh. This will maintain a constant level of alkalinity without fluctuations.
- You will need to calibrate each dosing pump before use. Use the instructions given by the manufacturer to calibrate properly.
- You may need extra tubing or a tube holder. You can even color-code your tubing to the elements being used.
- Check for any kinks in the tubing before use. Here is a video to explain.
Thanks for reading!
David has been keeping saltwater tanks for over 15 years. Learning and writing about all things related to saltwater aquariums is a passion and there is so much to learn and enjoy.
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