Factors influencing Alk depletion rates?

[ScubaSteve]

I'm with Tim on these and agree that it's likely a limiting nutrient, temperature or pH that is causing this. I find that my alk depletion rates drop like a rock if pH stays below 8 for any considerable amount of time (like it has recently). With the doors and windows being closed now, watch your temperature and pH.

Now, if you are using ULNS this could be the cause for sure. Try loosening up on your regime for a bit. You may find the system still stays at zero for N/P after doing this, it just means the corals are taking up a bit more of the nutrients and aren't having to compete with the bacterial colonies as much.