stable alkalinity for corals

[LyraFusion]

My tank's alkalinity keeps swinging between 7 and 9 dKH. I'm dosing two-part but can't seem to lock it in. Anyone else dealt with this? Running a 75-gallon mixed reef with T5/LED hybrid lighting, weekly 10% water changes, and a Reef Octopus skimmer.

[north9]

What's your dosing schedule like? I had similar issues until I switched to dosing smaller amounts more frequently. My 120-gallon runs at 8.5 dKH now, dosing every 6 hours via a Neptune Apex. Also, check your magnesium levels—low Mg can mess with stability.

[microbe]

What's your dosing schedule like? I had similar issues until I switched to dosing smaller amounts more frequently. My 120-gallon runs at 8.5 dKH now, dosing every 6 hours via a Neptune Apex. Also, check your magnesium levels—low Mg can mess with stability.

Yep, seconding the Mg tip. Mine was at 1200 ppm, and things got way smoother after bumping it to 1350. Using Red Sea Coral Pro salt here, 40-gallon cube.

[florist]

Are you testing at the same time daily? Alkalinity can dip overnight if your corals are growing fast. I test at 8 AM and 8 PM to catch swings. My Acros were bleaching until I caught the pattern. Now I dose extra at lights-out.

[peaceandpain]

Honestly, two-part never cut it for me. Switched to a calcium reactor last year, and my alk's been rock-solid at 8.3 dKH. Yeah, it's pricey, but no more daily dosing headaches. 90-gallon SPS-dominated tank, CaribSea substrate.

[flintech]

Honestly, two-part never cut it for me. Switched to a calcium reactor last year, and my alk's been rock-solid at 8.3 dKH. Yeah, it's pricey, but no more daily dosing headaches. 90-gallon SPS-dominated tank, CaribSea substrate.

How's the pH with your reactor? I've been eyeing one but worried about CO2 buildup. Running a 60-gallon with Zoas and LPS, dosing manually for now.

[brinyveg]

Dunno if this helps, but my alk stabilized after I stopped chasing numbers. Let it sit at 8 for a week, only adjusted if it dropped below 7.5. Weirdly, my corals looked happier. 30-gallon nano, weekly 5% changes, no skimmer.

[LyraFusion]

Thanks for the tips, everyone. Gonna test Mg and maybe tweak my dosing schedule. Appreciate the real-world advice!

[darwin]

Stability's key, but don't stress too much. Corals adapt. My 50-gallon's alk bounces between 7.5 and 8.5, and everything's thriving. Just keep changes gradual. You got this.

[trigade]

What salt mix are you using? Some brands have inconsistent alk levels straight out of the bag. I switched to Fritz RPM after my old mix gave me wild swings. 100-gallon mixed reef, monthly 15% changes.