Concerned about Ca

[mermaid_life]

I am very concerned. It's been over a month and I haven't had to dose Ca at all! Everyday my alk usage is 0.3dkh consistently and I dose daily with the Seachem reef buffer because I have low pH if I don't. pH fluctuates from 8.08 to 8.2 night to day like clockwork and has been this way for several months.

This all started with a power outage. Prior to the power outage, my tank was using 10-15ppm of Ca daily and everything had been looking the best it has ever been. Then I had a 6 hr power outage. Lost 1 acro frag. I was in the middle of fine tuning nitrate and phosphate because my sps were brownish and I read too high nitrate and phosphate could cause it so i was playing around. Well my phosphate dropped too fast and I got a minor outbreak of dinos that followed the outage. I treated the dinos with manual removal and vibrant, which took about 1 week. No more dinos now. Just minor cyano and light green algae dusting that my CUC is taking care of. I didn't change my water for 3 weeks because of dinos so I didn't have any Ca replenishment from water changes. Coraline is still actively growing on my glass daily but there is no drop in Ca for 3 weeks! How is this possible? I dose nothing else but alk/buffer.

Here are my params:
alk 8.0 per salifert
Ca 420-430 per salifert and red sea tests multiple times
Mag 1280
pH 8.08 to 8.2 per apex
Nitrate somewhere between 10 to <25 per salifert - hard to tell exactly. I did water changes weekly prior to outage to maintain closer to 10.
Phos: not zero, close to 0.1 - hard to tell with Salifert test
salinity: 1.025 consistently per refractometer, ~33.5 on apex probe consistent

I have no to minimal polyp extension on SPS as well which is also different pre and post power outage.
LPS look a bit ticked but not totally closed up.
No changes to temp or lighting.
I have a grounding probe
RODI
No salt changes
Fish and shrimp seem normal - hungry as always

Just trying to think of all the common questions and asks....... Any insight appreciated!

 

[Randy Holmes-Farley]

The expected calcium usage in your tank (with alk usage of 0.3 dKH per day) will be less than 2 ppm per day, so it will take a good while to detect it reliably. I wouldn't worry about it. Water changes alone might maintain it.

 

[mermaid_life]

Thank you so much. That's great to know.

I wonder then how come before the power outage the testing seemed to show 10-15ppm of Ca usage daily? This was consistent for a few weeks after I added SPS frags. I was manually dosing at the time and every morning testing around 9am.

 

[Randy Holmes-Farley]

Thank you so much. That's great to know.

I wonder then how come before the power outage the testing seemed to show 10-15ppm of Ca usage daily? This was consistent for a few weeks after I added SPS frags. I was manually dosing at the time and every morning testing around 9am.

I don't know, but that is far more than can possibly be consumed if the alk consumption really was 0.3 dKH per day.

 

[mermaid_life]

I trust science! Thank you I feel so much better about the ca.