- Ocean DKH or Alkalinity is at 7
- Ocean Salinity is at 0.024-0.026
We have the best results when we try to imitate nature.
Ideal aquarium DKH for corals/fish/invertebrates is 7-10.
The type of salt that you use has specific instructions about the source of water you use to mix with. For example… Fritz salt when mixed with RO water creates a mixed water DKH of 8-9. Fritz salt when mixed with tap water creates a mixed water DKH of 13-14. So, it is important to know DKH can differ greatly if you don’t follow the salt manufacturer instructions. This does not mean that you should only use RO water, this means that certain adjustments might have to be made depending on what your water mixes at.
In our experience coral dies rapidly if aquarium DKH goes over 10. Specifically, LPS and SPS. Fish and soft corals tend to be more tolerant of high DKH but it is still hard on them. Low DKH below 7 is also capable of causing tissues of coral to die quickly. Products exist to raise or lower DKH. However, these products should never be added directly to an aquarium. Make sure to mix/alter water chemistry outside of the tank.
The only regular testing you actually need to do when reef-keeping is salinity and DKH. The world is full of people trying to sell products. Most of which you don’t need. We often hear people testing for many things they don’t have to. If you do regular water changes and nutrient exporting all the trace elements and waste should be kept under control. No need to buy all the test options in most cases.
When adding top off water you can also change your aquarium DKH depending on water sourcing
For example… If you add dechlorinated tap water to your aquarium when doing a top off you are lowering the salinity but you are raising the aquarium DKH.
If you add RO water to your aquarium when doing a top off you are lowering the salinity but you are also lowering the DKH.
If you have the option to alternate between water sources you can top off with either to sway the Dkh in the direction you need.
