How low can alk go to?

[Oscar Bravo]

I had always tested my alkalinity at 8.5+/- with my doser. But recently I think something is wrong with it because my alk is at 7.0 (Salifer and RedSea). My notice my Red Dragon rtn one of his branches and my Digi a whole branch. Are they RTN due to my Alk. I cant find another reason.

 

[jda]

I have had mine get down into the high 4s. I am not recommending this... just did not watch it closely enough before I turned my CaRx output up. In my case, it took months to get that low.

IMO, anything above 6 is fine unless you are trying to run Zeo, or the like and are dosing organic carbon. 7 is good. 8.5 is good. I would worry more about how stable it is and less about what the value is.

If those corals did RTN because of the alk, then it was likely because of a swing, not a low absolute number.

 

[BoomCorals]

I have had mine get down into the high 4s. I am not recommending this... just did not watch it closely enough before I turned my CaRx output up. In my case, it took months to get that low.

IMO, anything above 6 is fine unless you are trying to run Zeo, or the like and are dosing organic carbon. 7 is good. 8.5 is good. I would worry more about how stable it is and less about what the value is.

If those corals did RTN because of the alk, then it was likely because of a swing, not a low absolute number.

What this guy said.

 

[Oscar Bravo]

I think the change happen within a week, not from one day to another.

I recently just added about 11 frags and a few weeks before I added a few large frags. maybe this can be it. MY phos is at almost 0 and nitrate at 20 all the time.