How much is the question...

2015GaTor · Jan 30, 2018

I have a question about dosing. I have not dosed my tank before. I have a 125g tank with 29g sump with about 100lbs of live rock that is a year and a half old. I do water changes each week (15 gallons each week). Over the last month or so I have noticed that my alkalinty has dropped steadly while my other levels have stayed somewhat constant. See levels below:
12/31 salinity 1.025, calcium 430, alkalinity 6.8, mag 1440
1/8/18 sal 1.025, Calcium 425, alkalinity 6.4, mag 1400
1/16/18 salinity 1.025, calcium 420, alk 6.3, mag 1400
1/23/18 salinity 1.025, calcium 430, alk 6.1, mag 1420

I dosed sodium bicarbonate to get the alk up to 7.5 over a few days but not sure how much I should dose to keep it there and maintain other levels any help would be appreciate? I have read you should dose the same amount of two part otherwise your levels will go out of wack. Thanks in advance for your help.

Justfebreezeit · Jan 30, 2018

https://www.bulkreefsupply.com/reef-calculator/

2015GaTor · Jan 31, 2018

I get there is a reef calculator. I assume I take the week to week difference in the alkalinity to get to the number I need? If the other two stay fairly constant do I use the same amount of two part even if it wouldn’t call for that much?

Justfebreezeit · Jan 31, 2018

Right, so divide the weekly difference by 7 so you get your average daily consumption. Then Dose that amount daily.
There is a few tricks like dose the Calcium portion during the day and the Alk portion at night to help stabilize PH.
Remember dose the alk portion as slow as possible.

Most people do equal parts of the two part as that what its designed for and calcium is harder to accurately test. (from what ive read)

Dont be afraid to ask specific questions. Everyone here is really nice.