Dosing help.

[SashimiTurtle]

A little background on my setup, I have an IM 14g peninsula. Kessil A160 for light, 565gph hydor powerhead inTank filter basket with a filter pad and reef spec carbon. I have red sea blue bucket salt and red sea fountain powders mixed according to directions.

It's SPS dominant with only two small duncan colonies. I have been trying to keep up with my big three thru water changes and manually dosing from time to time and after a few coral losses and some others that weren't doing well, I decided to go what the heck an auto doser to obtain more stability.

My question is, what would cause Alk to drop seemingly overnight from 8.1 to 7.5, then stay there for over 24 hours? Water changes are performed on Wednesday and Saturday, and usually consist of 2 gallons. All this Ca and Alk stuff has me thoroughly confused at the moment.

 

[Randy Holmes-Farley Verified Community Expert]

I'm not sure how to interpret your data since I'm not sure what is being dosed, but in general, alk declines over time and seems to decline much faster during the day than at night in typical reef tanks.

 

[SashimiTurtle]

Water changes on 2nd, 5th and 9th. 2ml of Red Sea part A added on the 9th with water change. Ca was low. Nothing else has been dosed in the time frame of my graphs. Ca went back up to 425 and has stayed there. Alk has always been 8.0ish right after water change and gradually fell... recently you can see it took a nose dive to 7.5 and stayed there. Is that where I need to keep my alk? I've been trying to hold 420, 8.0 and 1320 on my numbers because that's what my salt mixes to at 1.025sg.

 

[Randy Holmes-Farley Verified Community Expert]

Water changes on 2nd, 5th and 9th. 2ml of Red Sea part A added on the 9th with water change. Ca was low. Nothing else has been dosed in the time frame of my graphs. Ca went back up to 425 and has stayed there. Alk has always been 8.0ish right after water change and gradually fell... recently you can see it took a nose dive to 7.5 and stayed there. Is that where I need to keep my alk? I've been trying to hold 420, 8.0 and 1320 on my numbers because that's what my salt mixes to at 1.025sg.

If you want to maintain alk a bit higher, I'd start regularly adding small amounts of both parts of the two part and see what happens after a week or so. Don't try to base dosing changes on single daily measurements alone as there is often too much random variation in the results. Look more to the trend.