Seachem Reef Builder Biological Enhancer
Reef Builder raises carbonate alkalinity without immediately affecting pH. With long-term use, it may stabilize pH at 8.3. Carbonates and calcium are essential for coral growth. A deficiency in either will halt coral growth and lead to rapid decline in coral health. To prevent this, provide carbonates using Reef Builder and calcium using Reef Advantage Calcium or Reef Complete.
Reef Builder does not deplete calcium, magnesium, or strontium, which often precipitate when alkalinity increases. Reef Builder can be used alongside Reef Buffer. Use Reef Builder to increase carbonate alkalinity without altering pH. Use Reef Buffer to increase both alkalinity and pH.
Alkalinity Target Range
| Alkalinity Level | Equivalent Range |
|---|---|
| 3–5 meq/L | 8–14 dKH |
FAQ
Can Reef Builder be used with Reef Buffer?
Yes, Reef Builder and Reef Buffer can be used together.
Does Reef Builder affect calcium levels in the tank?
No, Reef Builder does not deplete calcium levels when used as directed.
What is the recommended alkalinity range for coral health?
Alkalinity should be maintained between 3–5 meq/L (8–14 dKH).

Keith Russell –
I’ve used Reef Builder for several months in my reef tank. The alkalinity has stayed stable without any sudden pH shifts. My corals have grown steadily, and I haven’t had to adjust calcium levels frequently. It’s a reliable supplement for maintaining carbonate balance.
Madeleine Glover –
Good product for raising alkalinity without affecting pH. Works well with my existing calcium supplement. I noticed a slight stabilization of pH after a few weeks, which is expected. Easy to dose and no visible side effects.
Rachel Edmunds –
Since adding Reef Builder, my tank’s alkalinity has remained within the ideal range. Corals are thriving, and I haven’t seen any signs of stress. It’s a simple, effective solution for maintaining carbonate levels.