photoperiod, longest healthy period is?

12 hours is a good standard.

Realistically you could run the lights 24 hours, and
it would not be the end of the world, but I would
not recommend a 24 photo period for a reef tank. You
want to keep it as a natural ecosystem.

But if say, you had a rearing tank just for corals,
you could run it 24 hours, and would most likely get
much faster growth. But algae and cyano could be a
problem. :-)

Wayne Sallee



wolfdogg wrote on 10/31/2007 12:54 PM:
what is the longest photo period that is healthy?

i usually follow the California sun over here, but i guess it would be
better to follow an equatorial sun since this is where the reefs grow
most i believe, where all the days run into each other, and the
seasons are mostly the same.

i am just barely starting to shift(reduce) from the long 14 hr
daylight period this year, after neglecting to adjust the timer until
recently.

the daylight savings time will come soon too so i am planning for that
as well by reducing timer by about 15 minutes(4 times) every other day
or every few days once i calculate when the time change will be, or
shortly after the time change should it come before i get it
adjusted. i do this for my own pleasure, so the tank will still be on
when i want it on, not because im an idiot that thinks that the fish
can benefit from the time change, :-)

my main interest is would 14-15 hrs of light not give the creatures
enough time to rest?
i realize it grows more algae, but i only have a small patch of
cyanobacteria, and 1 very small rock (about 2 inches diameter) that
has 2 patches of growing GHA on it that has been stable for about 6
months now at least. no other algae in the 29gal aquapod except below
the DSB line which the Cerith snails take care of the top half of that
regularly.

actually i think i had it come on at 9am, and off at 12pm, giving them
15hrs, for almost the last 6-8 months, and haven't had anything die on
me except a couple shrimps, and Astreas due to lack of water changes
and/or over alkalinity(19dkh) during that time. 2 of my 4 fish are
over a year old and the only fish i lost was a lawnmower blenny due to
lack of food supply for him :-() my bad should have supplemented.

i always hear peoples talking about a 12hr photo period, im thinking
almost assuredly this is why some areas of my glass(near the high
lumen output) gets green crust on it, and why the GHA on one of my
rocks thrives so well, and why some cyano persists(a little is always
beneficial in case of a toxic tank it will come to the rescue)

any opinions on the longest safe photoperiods experienced that does
not encourage GHA and other slime uglies?