Reverse Lighting in 'Fuge - Why?

[dnader]

I've been reading up on 'fuge lighting and reverse 'fuge lighting, and I'm a bit confused.

I think I understand some of the benefits - mainly nitrate removal and PH stabilization during the dark hours of the DT.

But, aren't the bulk of the nitrates built up during the lit DT cycle?

I am assuming that nitrates have a high(er) creation cycle during the time the DT is lit, and easing off during the dark hours.

Or, do I not understand that correctly?

How much Chaeto (for example) growth happens during a 'fuge dark cycle? I am also assuming that while there is some, it is drastically reduced therefore reducing the nitrate removal during the dark cycle.

So, is the reverse lighting of the 'fuge from the DT mainly for reducing the PH (and other swings) in the DT during light and dark hours?

I imagine that the reverse lighting of the 'fuge would cause nitrates to actually attain a higher point throughout the lit DT cycle.

As I see it, each cycle (nitrate, nitrite, Ph, etc.) probably happens similar to a sine wave throught the tank's daily cycle due to the combination of 'fuge and DT (and whatever other filtration/treatment may be in effect).

Wouldn't the peaks of that sine wave be higher if maximum Chaeto growth happened opposite of DT tank lighting?

That leads me to think that there really should be two 'fuges on opposite lighting cycles of each other so a 'fuge system is always lit while providing down time for each 'fuge.

Please help me to understand this better.

* edit * To a mod...please move this to the proper forum if this not in the correct forum

 

[stricknine]

WOW! I never bothered to think that hard in to it, but now I am a little (tiny) bit curious!

Now I am willing to throw this out there, but I think you answered your own question. As far as stability and processes go, DT during the day, sump at night. In my opinion (and I am not a professional by no account) a 24 hr processing plant is more efficient than a 12 hour shop. The 12 hours stale at night is counter productive to the 24 hour plant.

 

[Randy Holmes-Farley]

The main purpose of reverse or 24/7 lighting is to offset the consumption and production of CO2 and O2 that happens during the day and night cycles.

I don't think there is much evidence about when nutrients are most generated or used. Most ammonia and phosphate comes from fish excretion as they digest foods. That will happen for some period of hours after consumption. In people it can be days, but it is probably faster in a fish, and they will certainly excrete wastes at night.

Macroalgae may take up nutrients at any time. There is no reason to think they only do it when lit. Also, most tanks have a reservoir of nutrients available, so they do not disappear and then reappear diurnally.