crushed coral question

[odiechef]

...after time will it lose it's ability to boost KH?

This seems to be the case in my tank, while the GH seems to still be maintaining at it's higher level. The corals been in a couple of years.

water left overnight...1d KH
2d GH

tank water.....2d KH (it used to be higher)
8d GH (where it's been)

Thanx

 

[RTR]

It can, but none are sudden. First off it does dissolve - that is how it works. So what you put in 2 years ago weighs less than it did then, so from that factor can do less of the needed job.

Next, it also can and does support biofilm growth on the surfaces of the grains. Depending on the particular colonies growing this may block the ease of dissolving from simple reduction to cut-off of current. This can be counteracted by removal and rinsing if the coral is bagged in a filter. If it is incorporated into the substrate, the better the substrate is vacuumed, the better the water flux through it will be. On the other hand, some biofilms are acid-generating, so may enhance the solution of the base material.

Finally, the higher the pH in the tank, the slower the material will dissolve. But this is part of the strength of using such material - it does have a benficial feedback loop.