Experiment with bumping pH to 8.6

[JWsticks]

My current tank is 150G stuffed with SPS and currently dosing daily 180ml of sodium hydroxide and 2.9 liters of calcium hydroxide. pH ranges from 8.1 - 8.6 daily.

Lights come on at 10am and experimented with driving pH up to 8.6 by dosing 40pct of the daily alk consumpton in the first 4 hours of the 12 hour photoperiod.

The system was not happy after reaching 8.6 and had a minor alk spike of 1dkh yesterday. Noticing the same behavior today, I stopped dosing sodium hydroxide, dimmed the display lights and shut off refugium lighting until pH dropped to 8.5 and then resumed the normal light schedule.

What was interesting was pH remained around 8.5 and alk resumed consumption. Normal alk is 8dkh and shot up to 10.3dkh during the 2 days of experimenting.

All anecdotal and experiment was very short lived but wanted to share my experience for those chasing the pH dragon.

Pls do share if you've also reached 8.6 pH and saw any noticable impact on alk consumption.

 

[Randy Holmes-Farley Verified Community Expert]

My expectation is that it was the alk spike, not the pH at 8.6, that disturbed corals.

 

[Miami Reef]

Higher pH will lead to more alkalinity consumption, both from biotic (more coral calcification) and abiotic (precipitation on heaters). Are you dosing calcium chloride along with sodium hydroxide? If not, calcium will slowly decline as you maintain alkalinity with NaOH.

 

[JWsticks]

My expectation is that it was the alk spike, not the pH at 8.6, that disturbed corals.

Prior to this I've also tried dosing 75pct of the daily alk consumption equally during the 12 hour photoperiod and alk was fine next day.

Agree most likely corals were not happy with the magnitude of the alk dosage.

 

[JWsticks]

Higher pH will lead to more alkalinity consumption, both from biotic (more coral calcification) and abiotic (precipitation on heaters). Are you dosing calcium chloride along with sodium hydroxide? If not, calcium will slowly decline as you maintain alkalinity with NaOH.

I bolus dose calcium separately 2 times a week. Will invest into a doser once I can make room in the cabinet.

 

[Miami Reef]

I bolus dose calcium separately 2 times a week. Will invest into a doser once I can make room in the cabinet.

That’s fine IMO. Calcium depletes very slow relative to alkalinity, and its stability is not nearly as important. I’d personally have no issue bolus dosing once a week; twice a week is even better for stability if you’re doing that.

 

[Troylee]

8.6 is good! My tank loves it..