When do we test our Alkalinity? Best Practices

[Science/G]

So alkalinity is of course one of those major parameters that we focus on as reekeepers. Maintaining our alkalinity can be accomplished through various different methods all of which most are aware of, so we won't get into that. Testing and dosing are the obvious way to maintain our alkalinity in our desired range, but those of us that are still using traditional testing devices just get a one-time picture. That's where the time of day becomes a factor. Alkalinity is highest about 2 hours after lights on in the morning, so that seems to be the best time to actually test. This is something that I just learned recently. I hope it helps. Happy reefing.

 

[dloberry]

First test you your alkalinity at the same time each time you test. Second if you want to dose, i would test each day and then dose each day to get to the dkh you want to keep. Doing this over a 2-3 week period will tell you how much you are using. After you set up a dosing plan, then you can cut back to once per week or if you are comfortable once per month. The most important thing is test at same time each day

 

[Ziggy17]

interesting. I test at 8am every day as it’s in between the am AFR doses (6&10am). What makes alk highest 2 hours after lights on?

 

[Randy Holmes-Farley Verified Community Expert]

On its own, alk only generally declines, and more during the day.

If you dose evenly 24/7, alk will be highest in the morning before alk demand ramps up over the lit part of the day.

But if you dose on any other schedule, the peak and dip will be a balance between the demand and the additions.

 

[Ziggy17]

On its own, alk only generally declines, and more during the day.

If you dose evenly 24/7, alk will be highest in the morning before alk demand ramps up over the lit part of the day.

But if you dose on any other schedule, the peak and dip will be a balance between the demand and the additions.

That’s in line with what my thought process was. Lights off means less uptake. I dose 6x a day, and the daylight doses are slightly higher ( 2cc per dose) than the lights out doses to try to compensate for the higher day consumption.

The end result is the same 8.7 ish reading every morning. Usually with a .1 margin of swing.

 

[exnisstech]

I usually test about 1 hour after lights on. Mainly because I normally don't get up until lights come on and that gives me time to wake up first. No dosing is scheduled before the testing time and all starts afterwards.
Ive always tried to test at the same time every day for consistency sake. I don't monitor alk or auto test. I usually only test once a week unless I'm watching consumption to adjust my dosing amount.

 

[dloberry]

I usually test about 1 hour after lights on. Mainly because I normally don't get up until lights come on and that gives me time to wake up first. No dosing is scheduled before the testing time and all starts afterwards.
Ive always tried to test at the same time every day for consistency sake. I don't monitor alk or auto test. I usually only test once a week unless I'm watching consumption to adjust my dosing amount.

When manual dosing this is the best plan

 

[Science/G]

When manual dosing this is the best plan

That's an interesting thought one that I just considered myself. First of all I think it matters what you're dosing for alkalinity, secondly it seems that time of day matters for coral uptake @Randy Holmes-Farley are we on the right track here?

 

[CHSUB]

I dose when ph is the lowest, so at night for about 12 hours, both 2 part and kalk. During the lights on period I dose calcium. I’m not sure how much Alk fluctuates in a 24 hour period but various times of day shows Alk between 6.4 to 7.5. IDK if a different schedule method would yield better results, but my pH gets to 8.7 and I’m afraid to dose Alk then.

 

[Randy Holmes-Farley Verified Community Expert]

That's an interesting thought one that I just considered myself. First of all I think it matters what you're dosing for alkalinity, secondly it seems that time of day matters for coral uptake @Randy Holmes-Farley are we on the right track here?

Alk demand is substantially higher during the day. It’s not clear to me how much of that relates to actual light and how much to the pH being higher then. I’ve waited many years for someone with a large reverse lit refugium with pH higher at night to make the distinction.

When to dose depends on whether you want to stabilize pH the most, or alk the most.

When to measure alk depends on what you want to learn from it.

I dose AFR in the AM and measure alk typicallly mid day to afternoon.

 

[Terry Le]

My doser are going every hour 24/7. I dose Randy’s recipe 2 Alk to make up for Alk uptake because of my Calcium reactor can’t keep up. Test in a few days same time in the morning