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Changing Dosing Products

As the title suggests, I recently changed dosing products.

This all started because Seth is moving. (And will be setting up a bigger tank! YAY!) He brought me some corals to babysit until his tank was up and ready to go. As a thank you, he brought me some left over dosing chemicals from BRS. Which was really good, because I was nearly out of alk and my new bottle had not come in yet (thanks COVID).

Before this, my tank had finally seemed to hit the sweet spot. My acros are growing, their polyps are fluffy, everything looks happy and my calcium and alk consumption has been gradually increasing. Once I put Seth's corals in, it seemed to really take off. I keep increasing my alk dosage, but the alk level keeps dropping on the trident and confirmed with a hannah checker. I've been trouble shooting...

  1. Is there liquid in the bottle?

  2. Yes

  3. Is the dosing tube fully submerged?

  4. Yes

  5. Is the line clogged?

  6. No

  7. Is the doser actually moving liquid?

  8. Yes

  9. Is the bottle Seth gave me actually Alk?

  10. Yes

  11. Did he mix it correctly when he made it?

  12. Yes

  13. Well what is the difference in concentrations between what I was using and what I switched too?

  14. We don't know.

After some investigation, we concluded that this may be a reason why some people may struggle when they switch dosing products. It seems intuitive that when you changed products, you would check how much you need to add of a product to raise it a given amount. For me, my tank was having minimal change, and the uptake was predicted. By the time we got to #7, my alk needed to come up significantly. I like to keep it at 8.7 and it had dropped to 7.6. It turned out, I needed 4 times the amount of the BRS sodium bicarbonate to see the same increase in alk as my SeaChem Fusion 2 Part that I was using.

This is something I suspect I will always consider moving forward, but one of our missions will be to support new reefers so that they persist in the hobby. If you are changing dosing products. Check their concentrations. Luckily, there are calculators online. Here is how we checked four pretty common alkalinity dosing products this morning.

To the right, you will see the BRS dosing calculator inputs. ( found at They have a video on the page to explain how to input the variables. In this particular screen shot, I have chosen alkalinity as the element and liquid sodium bicarbonate as the product, as that is what I just change to. You also see the options for the type. The type I chose was New Pharma Pouch. For each calculator I used, I said I had 70 gallons of water, that my current alkalinity was 7.3 and that I wanted to raise the alkalinity to 9. It is really important that you stick with the same numbers you start with for each product. Even if you do not need to raise your alk, make up a number you you can determine the concentration differences more simply. I will show you how to do that next.

In the first screen, you can see the dosing calculator for the dosing chemical I was using: Seachem Fusion 2 Part. The dosing calculator can be found here: It takes 36.3 ml to increase the alkalinity from 7.3 to 9 dkh in a 70 gallon tank. Let's put this in a chart to keep track....

Seachem Fusion Part 2 Required Product Amount: 36.3 ml

BRS Sodium Bicarbonate Required Product Amount: 170 ml

ESV B-Ionic Bicarbonate Required Product Amount: 229.7 ml

BRS Liquid Soda Ash Required Product Amount: 85 ml

It's pretty apparent that these dosing products vary widely in their concentrations as they each need different amounts of the products to change the alkalinity concentrations inside the tank. Before I changed, I was seeing increases in alk consumption, but was relatively stable. This means the first think I need to do is figure out what my base line consumption is - this is the amount of alk I was adding every day to keep things stable. I know this because I was using my trident to dose. I was dosing about 12 ml of the SeaChem Fusion a day. This amount kept my tank around 8.8 dkh.

The next thing I want to do is figure out the ratios between each of the chemicals I put into the doing calculators. I do this by dividing the number for SeaChem fusion (this was what I was already using) by each of the other numbers.

BRS Sodium Bicarbonate Required Product Amount: 170 ml / 36.3 ml = 4.7

ESV B-Ionic Bicarbonate Required Product Amount: 229.7 ml / 36.3 ml = 6.3

BRS Liquid Soda Ash Required Product Amount: 85 ml / 36.3 ml = 2.3

So to keep stable alkalinity when changing from Seachem Fusion Part 2, I would have to multiply my current dosage of the dosing product times whatever number matches the new product I am switching to. Please note that this calculation would be different if you were changing from something other than SeaChem Fusion Part 2. The steps are the same, but you would use different numbers.

Since I was dosing about 12 ml of Seachem Fusion Part 2 per day, and I am switching to BRS Sodium Bicarbonate, I need to multiple 12 by 4.7 to get 56.4 to get back to my daily consumption.

12 ml of SeaChem x 4.7 = 56.4 ml of BRS Sodium Bicarbonate

If I had taken this into account when I first switched, all I would have needed to do was change my dosing amount. Since I did not, my alk has dropped, so I need to add more than 56.4 per day to account for my consumption and to increase my alk back to where I would like it to be (around 8.8).

When you increase or decrease a value, you want to do it slowly and in a planned way. You do not wank to see alk increase more than .5 per day. Since I need to increase a total of 1.7 dkh (9 - 7.3 = dkh), this means it should take me at least 4 days to do this safely. From my calculator, I know that it takes 170 ml of the BRS Sodium Bicarbonate to for from 7.3 to 9 dkh, without taking into account consumption. So I will divide that amount by 4,

170 / 4= 42.5

And add that amount to my daily dosing to get my alkalinity back to where I want it. This means that for the next 4 days, I will dose

56.4 + 42.5 = 98.9 ml of BRS Sodium bicarbonate

When you do this, you may want to consider testing alk multiple times a day as a redundancy to your calculations. My trident tests 4 times a day, and is pretty consistent with my Hannah. In my case, I will trust my trident to do it's 4 tests per day, and do an extra test with my Hannah checker one a day to make sure they numbers are similar.

Testing is always important, but it is more so when you are making changes in your tank. You don't want to wait until your pets are dying before you do something. The name of the game is not surviving, but thriving. Randy and Ryan recently made the analogy, if you don't realize your dog is sick until it's skin is falling off, your dog does not have the best life. We want to make sure we treat our precious corals with the same amount of love and attention and as a fluffy family pet.


Links for calculators:

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