Curious to know why... lighting & pH

[Daltrey]

My system is also fairly large - 300g. That probably helps stability as well

It definitely helps. The easiest way to maintain a saltwater tank is to go bigger.

 

[WWIII]

My system is also fairly large - 300g. That probably helps stability as well

The refugium definitely helps with the reverse lighting! Still strange given the circumstances. Could possibly bw the change in weather, but I would think that may trend the ph lower as well since the house is likely closed up tight. Interested to see what you come up with!

As a side note, maybe I need to do opposite lighting on my frag tank (same system) in the dark basement!

 

[TangingOut]

So, over the last little while I have been reducing the dusk/dawn period on my aquarium. I am now on an 8 hr full spectrum T5 schedule, with only 30 minutes each of dusk/dawn (total of 9 hours).

This is a big change from what I was running previously and given the reduction, I had assumed a negative (lowering) impact on my pH. Interestingly, however, I've noted the opposite. My pH has risen. Not a lot, but about 0.15.

Just curious why this might be...???

This is a bit of a head scratcher, but we need more info to figure this out. What was your light schedule before? Was it always 8 hrs full spectrum? How about your refugium lighting? Did that stay the same?

 

[CanadianReefer]

This is a bit of a head scratcher, but we need more info to figure this out. What was your light schedule before? Was it always 8 hrs full spectrum? How about your refugium lighting? Did that stay the same?

It was always 8 hours full spectrum, but I had a stupid long dusk and dawn setting -pure actinic from 7-10. I knew that actinic didn't give off as much par, but some of my SPS weren't responding well and when I looked into It, I found out that they were still able to absorb a lot of the actinic - so now it's 11:30-12 dawn, 8 hours full spectrum, then 8-8:30 dusk.

I haven't changed my refugium schedule. I had planned to, but when I realized my pH went up instead of down, I didn't bother. It is on at 10 and off at 7 the next morning

 

[CanadianReefer]

It was always 8 hours full spectrum, but I had a stupid long dusk and dawn setting -pure actinic from 7-10. I knew that actinic didn't give off as much par, but some of my SPS weren't responding well and when I looked into It, I found out that they were still able to absorb a lot of the actinic - so now it's 11:30-12 dawn, 8 hours full spectrum, then 8-8:30 dusk.

I haven't changed my refugium schedule. I had planned to, but when I realized my pH went up instead of down, I didn't bother. It is on at 10 and off at 7 the next morning

Actually, I'd have to check, but I think I was 9 hours full spectrum before. I'll look at my history and get back to you...

 

[TangingOut]

Are you growing macro in the refugium and has it had a boost in growth since the change?

 

[CanadianReefer]

Are you growing macro in the refugium and has it had a boost in growth since the change?

About the same growth... I usually take out a shopping bag's worth of chaeto every 2-3 days. I'll keep my eye on it to see if I notice more growth - i just took put a bag today. I also have devil's breath but it grows very slowly.

 

[CanadianReefer]

About the same growth... I usually take out a shopping bag's worth of chaeto every 2-3 days. I'll keep my eye on it to see if I notice more growth - i just took put a bag today. I also have devil's breath but it grows very slowly.

*Took out

 

[Cory]

As it gets colder the hvac heating system will bring in more fresh air, removing co2 from you home, or equalizing it with outside air, thus raising ph. Its not your lights imo, especially at night. You have a forced air furnace?

 

[Randy Holmes-Farley Verified Community Expert]

A bigger temp difference between inside and out brings in more air by natural convection into a heated home, so ph might rise with a temp drop outside:
here's a study:

Continuous measurements of air change rates in an occupied house for 1 year: The effect of temperature, wind, fans, and windows*
https://www.nature.com/articles/7500229

from it:

"Although a clear effect of indoor–outdoor temperature difference could be discerned, its magnitude was relatively small, with a very large temperature difference of 30°C (54°F) accounting for an increase in the air change rate of about 0.6 h−1."


While they say the effect "was relatively small", turning over the whole house air 60% every hour is a big effect if you are thinking about accumulating CO2.

 

[CanadianReefer]

That theory would at least make sense of an otherwise confusing result

 

[saltyfilmfolks]

Have you added more coral? Or has the fuge grown ? The corals I assume , have gotten larger.

It seems a minimal change in PH , so air quality , test error , more organisims pulling co2 may well account for the slight change.

I belive the old words of wisdom on not chasing ph was because it will change , as the corals get more numerous and larger.

 

[Vohlk]

Has the temperature in your tank changed at all temperature has an impact on co2 dissolution rates.

 

[CanadianReefer]

Has the temperature in your tank changed at all temperature has an impact on co2 dissolution rates.

No - nothing else has changed. I haven't added corals or played with the temp at all.

I'm noticing that my alk levels are dropping more rapidly now too, which would make sense with a higher pH. Though it's a positive change, my tank was stable where it was and now I will have to let it settle out again.

Thanks for all the thoughts folks! I always appreciate the responses, especially to my more obscure observations

 

[killr66tb]

I dose at night which keeps my ph above 8.0