Refugium light on for how long?

I just built a sump/refugium out of an old 20 gallon tall. I don't know how long to leave the light for the refugium on for. Is it 24 hours or will the refugium benefit from day/night like the main tank?

 

as you are already aware there are different schools of thought on this aspect

some light them 24/7
others run them 12 on 12 off - in order the plants can breath
some that do run them 12 on 12 off run the fuge lighting in reverse of the DT lighting
so when DT is on fuge light is off and come on when DT is off

the reason for this is to try and maintain the PH at night - when the fuge lights are off , the macros breath oyxgen and release CO2 ( a reversal of the day time activity)
CO2 levels can drop PH - so by running fuge lights in reverse of main lighting, they are trying to achieve a constant PH in their DT rather than the highs and lows that are often experienced in a tank with a fuge on same lighting cycle

which is best?

I have no idea but the reversed lighting scenario does appeal to me
Steve

 

I use the reverse lighting,helps with heat issues also as you're not burning all the lights at once.

 

This is correct. This man is too smart.....even for his own good.....lol

I run my fug on a reverse lighting schedule from my DT. My fug runs from 10pm to 10am. I'm not comfortable running a refug 24/7, even if its only with cheato. Plants need a break, besides, its not normal.



Luna

 

So I understand the thinking, but has anyone tested the reverse photo period out. I mean if you swapped it, how much would your PH be affected.

I ran a reverse, but then due to other considerations, now just turn off for 8 hours during the day. I have also ran the same periods and didn't notice much of a change in my PH either way. Now I just dose my Alk all night long and ph stays 8.2-8.3

 

I run my fige lights for about 18hours on a reverse cycle from my display. so there are 3 hour overlaps where both lights are on.

 

My ph maintains between 8.0-8.1 during the night, but thats naturally. What I mean by that is, your ph stays between 8.2-8.3 only b/c your dosing alk. Its almost like saying that your ph is a false reading. My ph is between 8.1-8.3 during the day, so its pretty stable during a 24 period. I hope that made any sense.



Luna

 

No... right. I realize thats why it is now... but before, I was not dosing Alk like that. It was before using 2 pt. I did not find the reverse period to affect PH much. So now, because of that, I dose Alk all night with the AC jr. See what I'm saying?

 

Yeah, I understand. But if you want an accurate "true reading" or to find out if the reverse lighting works, try it without the dosing of Alk.


Luna

 

OK! So this actually works out good. I've got a powerstrip with a timer that runs 2 DT lights and 2 NT lights. I'm going to run my fuge light in reverse then. Thanks All!!!