368 ml of Ca to much?

[Steve1500]

I am starting to manually dose my DT for Calcium and Alkalinity. I have a 75G tank (roughly 72G total w sump) and my current readings are 8.1 dkh and 340 ppm for Ca. I am trying to get to 8.5 dkh and 390 on the first day. I am using the BRS two part pharma. The BRS dosing calculator says ~20ml for soda ash and a whopping 368ml for Ca! Does this sound right to increase 50 ppm for Ca? Last night my Ca was 350 and today it is 340, so a 10 ppm drop. The BRS instructions say not to increase more than 50 ppm per dose, so that is why I chose 50 but I am concerned 368ml in one shot may shock the system. Should I increase more gradually?

Thanks!

 

[Dr. Reef Verified Sponsor]

1.4 dkh increase per day and 50 ppm per day on cal is max recommendations. So if you break that dose up over hours it would be just fine.

 

[Randy Holmes-Farley Verified Community Expert]

I agree I'd spread it out. Not so much because the calcium level jump is an issue, but for the potential for impurities in the calcium supplement.