Flow and alk intake

jason7570 · Jun 24, 2018

...so my alk has been pretty stable for years, anywhere between 8.1-8.4 ( I tested the day before) pretty much stays between those numbers. I decided to double my flow in my direct tank and frag tanks ( everything is hooked up together) because I felt like there wasn’t enough in all of my tanks. I tested my alk because my corals just didn’t look too happy and the reading was(Hanna and Red Sea ) 6.9 and 7.1. I know adding flow increases alk intake but dropping this much in a 24 hour period? Is there anything else I should worry about? It sucks because it took FOREVER to dial everything in correctly...

Randy Holmes-Farley · Jun 24, 2018

I can't see anything substantial to worry about, unless the device you are using to add flow is getting warm and precipitating calcium carbonate on its impeller.

It may not just be flow, but other factors that flow can impact, such as pH, that might alter the calcification rate, either by corals or abiotic precipitation.

jason7570 · Jun 24, 2018

Thanks. Yeah after checking my apex I had a pretty big PH swing also. My ph is like clockwork dipping at night ( I run a refugium also ) and rising when the lights turn on. I run my fuge at night but never seemed to help with my ph declining. The only thing else I can thing of is I fragged a lot of coral and used “cured” plugs.. would that affect the ph and caused my alk to drop?

Randy Holmes-Farley said:
I can't see anything substantial to worry about, unless the device you are using to add flow is getting warm and precipitating calcium carbonate on its impeller.

It may not just be flow, but other factors that flow can impact, such as pH, that might alter the calcification rate, either by corals or abiotic precipitation.