How Fast Should I Lower Alkalinity?

[BradVol]

My target Alkalinity is 8-8.5 dkH. Through neglect it crept up to 11.8 over 2 months. I adjusted my dosing to have it drop 0.2 dkH per day. Then I turned off my GFO and cleaned out some precipitation near where my dosing occurs and my Alkalinity shot up to 12.6 in one day and some corals aren’t happy. My guess is less is precipitating out now but it could have something to do with GFO.

I’d like to get it back to 8.5 or lower but don’t want to do it too fast. How quickly should I lower it with water changes and how much should I target it to fall per day while dosing? I turned off my DOS last night after noticing the rise. I’m due for a WC anyways and my new water is 8.5 dkH.

pH 8.0-8.15
Ca: 390, targeting 425
Mg: 1350
Nitrate: 7ppm
Phosphate: 0.05ppm
Salinity: 34ppt

 

[Spare time]

12.6 is fine. That isn't going to cause a serious issue. I have kept my tank at 11.5 for months. Just let it drop naturally or do some small water changes.

 

[Gtinnel]

I would aim for .5dKh change per day.

I know that GFO effects alkalinity but I'm honestly not sure why, I've never really used GFO so I've never looked into it.

 

[Randy Holmes-Farley]

My target Alkalinity is 8-8.5 dkH. Through neglect it crept up to 11.8 over 2 months. I adjusted my dosing to have it drop 0.2 dkH per day. Then I turned off my GFO and cleaned out some precipitation near where my dosing occurs and my Alkalinity shot up to 12.6 in one day and some corals aren’t happy. My guess is less is precipitating out now but it could have something to do with GFO.

I’d like to get it back to 8.5 or lower but don’t want to do it too fast. How quickly should I lower it with water changes and how much should I target it to fall per day while dosing? I turned off my DOS last night after noticing the rise. I’m due for a WC anyways and my new water is 8.5 dkH.

pH 8.0-8.15
Ca: 390, targeting 425
Mg: 1350
Nitrate: 7ppm
Phosphate: 0.05ppm
Salinity: 34ppt

Are you dosing anything?

 

[BradVol]

Are you dosing anything?

Yes, dosing 18.5ml of Red Sea Ca Powder to raise Ca 10ppm/day. Was dosing 66ml of Red Sea Alkalinity Powder which should have lowered Alk 0.2 dkH/day. I stopped dosing Alkalinity last night.

 

[MichaelReefer]

Just stop dosing and let it drop naturally.

 

[Randy Holmes-Farley]

Yes, dosing 18.5ml of Red Sea Ca Powder to raise Ca 10ppm/day. Was dosing 66ml of Red Sea Alkalinity Powder which should have lowered Alk 0.2 dkH/day. I stopped dosing Alkalinity last night.

I agree I'd just let it drop on its own, not try to push it faster by water change.