Alkalinity and Dosing Two Part

cmcimino · Mar 8, 2019

I am currently dosing two part on my 75 gallon mixed reef tank. Tank has been running about 9 months, and started two part dosing in January. Prior to that I was dosing kalk through my ATO. I test my Alk with my Hanna checker probably ever 2 days or so. Over the past week my alk has been consistently dropping from 8.62 to 8.12. Dosers have been running every day, and I am still seeing the slight pH increases when dosing the Soda Ash.

Right now I am dosing my alk at night, and my calcium during the day. Last night I tested my alk at 8.12, and today I tested it at 8.288. I dosed approximately 38 ml. I have a total water volume of 80 gallons. Shouldn't my alkalinity increased more than that over night, or do corals use up alkalinity overnight too?

saltyfilmfolks · Mar 8, 2019

Have you ever tested twice in a row (like minutes apart ) just to see if there is minor test error?

That’s a pretty small variance. IMO.

cmcimino · Mar 8, 2019

Yes, once with the Hanna and once with a Red Sea kit.

saltyfilmfolks · Mar 8, 2019

I’d try splitting the dose to am and pm. Or split it into four.

Honestly. I don’t see a problem with a .16 usage gap.

cmcimino · Mar 8, 2019

Sorry I may have worded that wrong. I have measured my alkalinity every night at 8 pm. I dose my alk from midnight to noon in 6 increments. Each night this week my alk has been a lower amount so my alk on 3/1 was 8.62, on 3/4 it was 8.46, on 3/6 it was 8.23, on 3/7 it was 8.12. Since it has been dropping over the week with dosing I have been increase the amount I dose. Today at noon (after my dosing) I measured it again and it was at 8.28. The amount I dose should raise the alkalinity .7 dkh. But it only raise .16 over night. I’m assuming my tank is using up alkalinity over night. Is that normal?

saltyfilmfolks · Mar 8, 2019

I only test alk weekly. Sometimes.

It’s totally a minor drop. I don’t even care if mine is .5 different. As long as it’s in the 8 range.

Up your dose a bit of you’re concerned.