Help me interpret my pH graph!

[Montiguy1287]

Can someone help me interpret his data? It's pretty regular but I'm wondering what is happening in each cycle. To me it looks like my ph increases each day. My lights start at noon which is where the increase starts each day. So that part makes sense that pH increases when lights are on. I'm wondering what's up with that jagged drop. My alk doser runs for a total of 6 minutes with a minute break in between 1 minute cycles.

Does alk dosing increase pH? If so, is that why my peaks steadily drop as the week goes on? Alk is being consumed throughout the week. Is my doser not keeping up at night? I can adjust to increase dosing.

I'm also wondering why it's so much different than pattern at the end. Yesterday's water change explains the spike drop since the probe is out of the water for a min but seems weird it would look that irregular.

Last question, is a swing from 7.22-7.85 detrimental to coral in any way? I imagine the ocean fluctuates but just checking.

 

[ncaldwell]

When does the alk turn on time wise?

here? Your swings aren't a problem imo, I have higher swings in my day/night ph cycle. I would wonder why your peak is gradually lowering at the days pass, is your alk/cal numbers also lowering as in increase demand from coral lowering your numbers? Also if your alk in the replacement water was different it would explain the weird bit, some salt mixes can and will be drastically different than what is in the tank so it's advisable to fix the alk and cal in the replacement water first

 

[Blueseatex]

I would say if your ph is actually hitting 7.2 that it would be detrimental to coral. I would try recalibrating your ph probe. Also make sure there are no wires crossing your ph probe.

 

[Montiguy1287]

When does the alk turn on time wise?

here? Your swings aren't a problem imo, I have higher swings in my day/night ph cycle. I would wonder why your peak is gradually lowering at the days pass, is your alk/cal numbers also lowering as in increase demand from coral lowering your numbers? Also if your alk in the replacement water was different it would explain the weird bit, some salt mixes can and will be drastically different than what is in the tank so it's advisable to fix the alk and cal in the replacement water first

It turns on at midnight right where the dips are. I do have good coral growth and I think increased demand is a solid theory. I dose calc/alk in the salt mix prior to water changes. Sometimes they are high with my salt mix (coral pro) in which case there's not usually much I can do to drop it to where the tank is. When it's high it's not usually by much.

 

[Montiguy1287]

I would say if your ph is actually hitting 7.2 that it would be detrimental to coral. I would try recalibrating your ph probe. Also make sure there are no wires crossing your ph probe.

I'll recalibrate tomorrow and see what happens. Good idea.

 

[Montiguy1287]

Well I've been tracking my alk all week to get an idea on how my dosing schedule is and turns out I was 21 mL per day short on correct dosage. Changed from a 4.5 minute total schedule to a 1.5 minute every hour for the 16 hours the lights are off. Ran first set of tests this morning and so far it's right in line. Can't believe how far off my dosing was. I need to re evaluate that more often...

New pH graph does peak in correlation with each time it doses so that helps solve my original questions.

Here's the new graph: