Seachem Reef Builder 300g
Reef Builder raises Carbonate Alkalinity (KH) without immediately impacting on pH. With long term use there will be a tendency to stabilise at pH 8.3.
Used as directed, reef builder will not deplete calcium, magnesium or strontium which usually tend to precipitate with increasing alkalinity.
Reef Builder & Reef Buffer may be used together. Use Reef Builder to raise carbonate alkalinity without affecting pH. Use Reef Buffer to raise carbonate alkalinity and pH.
Reef Alkalinity should be maintained at 3 – 5 meq/L (8-14 dKH), alkalinity should not be allowed to fall below 2 meq/L.
| Specification | Value |
|---|---|
| Product Type | Carbonate Alkalinity Booster |
| Weight | 300g |
| Recommended Alkalinity Range | 3 – 5 meq/L (8-14 dKH) |
| Target pH Effect | No immediate impact; may stabilize at 8.3 over time |
| Key Benefit | Does not deplete calcium, magnesium, or strontium |
FAQ
Can Reef Builder be used with Reef Buffer?
Yes, Reef Builder and Reef Buffer can be used together. Use Reef Builder to raise carbonate alkalinity without affecting pH, and Reef Buffer to raise both alkalinity and pH.
What is the recommended alkalinity level for reef tanks?
Reef alkalinity should be maintained between 3 and 5 meq/L (8-14 dKH), and should not fall below 2 meq/L.
Will using Reef Builder affect calcium or magnesium levels?
No, when used as directed, Reef Builder will not deplete calcium, magnesium, or strontium.

Sean King –
I’ve been using Reef Builder for several months now and it’s helped maintain stable alkalinity without raising pH. My tank’s pH has stayed consistent, which is great for my corals. No signs of calcium or magnesium depletion either. Works well with my existing setup.
Lucas Newman –
It’s easy to dose and keeps alkalinity up without spikes. I noticed my pH stabilized around 8.3 after a few weeks, which is what I was aiming for. I still use Reef Buffer occasionally when I need to raise pH too.
Joseph Knox –
The product is reliable and effective. I didn’t have to adjust other supplements because alkalinity increased without affecting my calcium levels. Very satisfied with the performance.