KH increases during the day

[stuyorkshire]

Anyone else getting KH increases during the day? Seems to be the reverse of what is expected.
Currently using a KH keeper to reactively dose pH plus and universal. I’ve managed to reduce variation by dosing less when the lights are on but the daily peak remains.
Blue is KH, big jump is a calibration issue, but the pattern remains the same. pH (green)is unlikely to be accurate due to the KH keeper, but again the pattern should be true.

Testing and dosing every two hours, but only recorded every 6h here.
pH plus and universal arei4.87 ml per day
Salinity 1.025
Nitrate 15
Phosphate 0.01 to 0.07 (currently dosing to try to increase)
Calcium 420

 

[josh57]

Not for sure why either, but my consumption shows a similar trend. (Also auto testing with a kh carer)

 

[Randy Holmes-Farley]

Can you blow up the graph to just 36 h?

 

[stuyorkshire]

Can you blow up the graph to just 36 h?

a bit more than 36h, but hopefully it helps.

 

[Randy Holmes-Farley]

Great. What times are your lights on?

 

[stuyorkshire]

Great. What times are your lights on?

11:00 to 19:00 then 3 hours of moonlight. Sunrise here is currently about 06:00 and sunset about 20:00.

 

[Randy Holmes-Farley]

Is it possible to know how much it doses each time? Maybe the alk consumption is mostly during the day, but it slightly overshoots the need?

 

[stuyorkshire]

Is it possible to know how much it doses each time? Maybe the alk consumption is mostly during the day, but it slightly overshoots the need?

It’s set to dose 0.39 ml hourly from 08:50 to 16:50 and 0.42 ml on the same hourly times the rest of the time. The last 24h with auto adjustment is on the attachment. No point = skipped dose.

 

[Jamie814]

Currently using a KH keeper to reactively dose pH plus and universal.

What is "universal"? Nitrate's being consumed can raise alkalinity as well.

 

[stuyorkshire]

What is "universal"? Nitrate's being consumed can raise alkalinity as well.

Sorry, it’s part 2 of Reef Zlements dosing. No nitrates in that, but I also dose 8 ml of Red Sea AB+ per day

 

[stuyorkshire]

Reef Zlements just came back to me with this:

We have seen that effect from the way/method your KH controller actions preform. You will be able to avoid that if you manage alkalinity manually or with other controller (other dosing approach).

So possibly not a tank process issue. @Randy Holmes-Farley’s thought about overshooting may be the answer. I’ll ask on the controller forum how Reef factory KH keeper actions vary from Zlements parent company DD’s controller’s method.

 

[Randy Holmes-Farley]

Sounds good. Let us know if you find out anything useful. :)