Photoperiod and pH correlation graphs

Myka · Jan 15, 2016

I don't have a controller or pH monitor. For those that do, could you please post your pH graphs (24 hours or a few days) and your photoperiod. Please include type of lighting and when blues and whites each go on and off. I can find pH graphs online, but haven't been able to find any that list the actual photoperiods.

Thanks for any help!

ScubaSteve-21 · Jan 15, 2016

I have a lab grade probe on my DA reefkeeper lite...I haven't done anything on the computer so I haven't seen any graphs...though I monitor my PH nonstop. There are a boatload of variables in play here...tanks size is a big big one here, dosing, sump light. All tanks will swing ph when lights go off, it seems the bigger the tank the less the swing is. So if you don't dose or use a sump light it can be noticeable. I have a nano (super happy 14g grows sps great) tank so unless you fit in that category I almost feel as though my data is irrelevant. But I run me blues 12ish hrs and whites 8ish hrs. I have noticed blues don't affect ph really at all. My ph swings as drastic as 7.8,7.9 - 8.3. I'd say highest ph is after 5+ hrs of whites, and shortly after they go off the ph starts dropping which is slow with blues and my sunset setting, and then drops fast when blues go out...sorry this is so much info and I don't have a picture :/ hope something helped lol ask if u wanna know more. I have an AI prime on my BC14

Myka · Jan 15, 2016

ScubaSteve-21 said:
I'd say highest ph is after 5+ hrs of whites, and shortly after they go off the ph starts dropping which is slow with blues and my sunset setting, and then drops fast when blues go out...sorry this is so much info and I don't have a picture :/ hope something helped lol ask if u wanna know more. I have an AI prime on my BC14

Thank you. This ^ is what I'm looking for. Nothing too specific. All I'm wanting to do is get a rough idea when my pH is lowest and highest in comparison to the photoperiod. I've been using my handheld meter, and have some data. I just want to confirm it. The purpose is simply that I dose kalk at night and calcium & alkalinity during the day, and I want to get the best use of the kalk's high pH.

Randy Holmes-Farley · Jan 15, 2016

pH is lowest just at lights on or slight after (especially if they are dim lights to start), assuming that other factors, such as dosing and CO2 concentrations in the home air, are not changing.

The pH max is typically near and slightly after the point where the brightest lights turn off.

Myka · Jan 16, 2016

Thanks Randy, I didn't think it was that quick of a change, I thought there would be a few hours delay.

I have an ATI dimmable T5 fixture. The blues run from 0800-2130 (10% for the first 2 hours just to extend feeding periods), and whites run from 1330-1930 (ramping up and down for the first and last 30 minutes).

From the information provided, I could assume pH will begin increasing around 1000-1200 and will begin decreasing around 1930-2100. So I could switch to kalk dosing between 2000-1000, and cal & alk dosing 1100-1900. Sound about right?