Will Dosing Nitrate Raise dKH?

landlubber · Feb 16, 2018

Hey guys,
I recently replaced my sump with a custom one that has a considerably larger refugium to resolve a longstanding nutrient and gha issue.
After a few weeks of watching the baseball sized chaeto ball expand into a 15"x15" dense mat I noticed some of my corals beginning to get pale. sure enough my nitrate and phosphate had bottomed out so I began dosing potassium nitrate and got it settled to 5ppm and feeding more. The issue I'm finding now is that while my nutrients are on spot my alkalinity has began to raise and hold over 1.0dkh higher than they were previously.
I plan to cut down 1/2 of the chaeto and reduce my skimming to work myself off of the spectracide but it got me wondering if this is a normal response to nitrate dosing?

LobsterOfJustice · Feb 16, 2018

Corals will slow down calcification if they are stressed, and you will notice alkalinity rise if you maintain the same dosing you used previously.

Randy Holmes-Farley · Feb 16, 2018

Yes, it is a response to nitrate dosing. When you add nitrate and it gets consumed, you get about 2.3 dKH of alkalinty for every 50 ppm of nitrate consumed.

landlubber · Feb 16, 2018

Randy Holmes-Farley said:
Yes, it is a response to nitrate dosing. When you add nitrate and it gets consumed, you get about 2.3 dKH of alkalinty for every 50 ppm of nitrate consumed.

ok so reducing the chaeto and skimmer run time along with reduction of nitrate dose should be enough to balance things back out again right? I just don't want to tinker with my staple doses if there is no need for it.

Randy Holmes-Farley · Feb 16, 2018

landlubber said:
ok so reducing the chaeto and skimmer run time along with reduction of nitrate dose should be enough to balance things back out again right? I just don't want to tinker with my staple doses if there is no need for it.

It may be hard to balance everything, but less nitrate dosing will lead to lower alk boosts from that process.