Changing activated carbon in sump

[Froggy]

Hello, I was wondering if some corals, SPS in particular, can be shocked by changing a sock full of carbon all at once located in the sump of a 75 gallon SPS,LPS reef. I usually use approximately 3/4 cup of Black Diamond activated carbon and usually only change it every few months. I was wondering if changing the carbon monthy would be better, and if it is, should I change only half of the carbon at a time or would changing all of it and replacing it with 3/4 cup of new carbon? Can and does this have a negative impact on the chemistry of my tank ?

[Randy Holmes-Farley]

While folks have discussed such shocks before, it is usually in the context of adding carbon for the first time, and then using it agressively (like in a pumped reactor). I think it unlikely that they water has become yellow enough to cause a shock in a situation like yours. Does the water become visibly yellow between changes?

[Froggy]

No, my water does not visibly change or yellow at all between my current schedule of changing the carbon. I have been running the carbon passively in the sump 24/7 since the beginning 3 years ago. I have been adding more and more SPS to my reef over the last few months and was worried about shocking them by changing all of the carbon at once.

[Randy Holmes-Farley]

I think that plan is fine. :)

[Froggy]

Ok, thank you very much for the quick help and peace of mind !

[Randy Holmes-Farley]

You're welcome.

Good luck. :)