Added sodium carbonate (ALK) while starting All For Reef

[Jimmyneptune]

My tank has been running for 10 years. I had been using two part for years; I decided to start using all for reef. I typically keep my DKH Around 9.0. Unfortunately, during my AFR set up, I left the sodium carbonate (soda ash) portion of my two-part run for an extra day. As soon as I found out my error, I stopped the two-part dosing of alkalinity. I have kept dosing all for reef.
On 9/30/2025 my alkalinity was 167PPM or 9.8 DKH on 10/1/2025. My alkalinity was 262 or 14.4 dkh. The 24-hour window was the time frame I ran both on accident. My calcium has been generally the same right around 350 PPM, the calcium did fall slightly on 10/2 and 10/3 to the 320 range.
As of 10/17/2025 my alkalinity is 215 PPM/11.7 DKH and 350ppm calcium. The alkalinity is slowly dropping, and the calcium seems a little depleted, but generally in the same range. What did I do to my tank? What’s the best way for me to proceed?

 

[tbrown]

You likely didn't do anything to your tank except potentially double up on Alkalinity. If it's falling, let it fall to where you want it and then adjust the AFR up to where it needs to be to stay level.

Where do you want to land for alkalinity? You can use the drop "average per day" to start planning your AFR dose needed to maintain stability. Figure out what it loses daily on average and calculate the AFR dose for that depletion amount. When you get to the level you want to maintain, adjust the dosage up by that amount.

However, if your calcium isn't dropping, you can consider dosing alkalinity in addition to the AFR instead of upping the AFR.


If your corals are good, then they survived the spike. Gradually falling in safer than rapidly dropping.