First, I think it’s important to note, this is a simple summary of how we manage our Alkalinity & Calcium. By no means is this the only way manage the Calcium & Carbonate needs of a Reef.
Consistency is something we all strive for in our reef, but there are different ways of achieving consistency. When it comes to Calcium and Alkalinity, we focus on providing a consistent, maintainable feeding or dosing frequency, creating a consistent cycle, rather than aiming to maintain consistent levels.
For most reefers we recommend a frequency of 1x per week dosing.
Once per week (aiming to do it on same day each week of course), we test our Calcium & Alkalinity.
| Alkalinity (dKH) | Calcium (ppm) | |
| Dose To: | 8.5 | 450 |
| Low @ | 8.1 | 410 |
If Neither is low – Do nothing – Wait another week before testing again.
If Alkalinity is Low (Under 8.1), and Calcium is NOT Low (410+) – Dose Alkalinity to 8.5 using Sodium Carbonate. (DOSING GUIDE for DRC Sodium Carbonate: 5mL will raise 100G of Water by 0.1dKH)
If Alkalinity is Low, and Calcium is Low – Dose Kalkwasr to Calcium of 450 (In instances where calcium is slightly low, but Alkalinity is significantly low, sodium carbonate may need to be added to a smaller Kalkwasser dose to bring Alkalinty to 8.5)
Once Using this method, you will find it impossible to even be low on calcium but not on Alkalinity unless a misdose or testing error occured previously, however, in this even we would use Calcium Chloride to increase Calcium to 450 without adding Carbonate.
What this means, is that when we test we are usually getting number between 6.8 and 7.3 on Alkalinity, and 370-400 Calcium, and in fact that is what we want to see, as the lower the number, the more consumption occurred since my last dose. So, when we get test results closer to our “Dose To” or Target numbers, that is actually the result of a lack of photosynthesis taking place, and our first indicator that we need to investigate what is limiting photosynthesis from happening.
If We were automatically dosing our tanks, even if we were still executing weekly tests, by the time we tested and discovered that photosynthesis had ceased, our tanks would be Overdosed, instead of simply remaining in their target concentrations, further contributing to the stress factors on the coral. Calcium at elevated levels become increasingly hard for corals to extract from the water column, making it even harder on a struggling coral, and overdosed alkalinity can lead to burned coral tips.
If you’ve never managed Alkalinity and Calcium, you will find this practice will take a few weeks to “get up to speed”, and it may be several weeks before you need to dose any calcium, don’t be discouraged, and don’t be tempted to overdose to get things going, trust in the protocol, and keep testing, because the week it finally moves, it will really start moving, and if you’re not reacting with it, it will be a short lived growth spurt.
