On Fri, 22 Sep 2006 04:20:03 +0000, Abraham Evangelista wrote:

I know that CO2 is used during lighted hours, and not used during the
dark. Thus, if one is trying to conserve CO2, or avoid stressing the
fish, CO2 injection is often stopped at night.

Is there some sort of similar rule to follow regarding nitrates? Do the
plants absorb them during the day, during the night, or constantly? Is
there any real benefit to dosing in the morning, or evening?

All the supplements I've purchased say to add enough to reach a certain
ppm once a week. Since there's so much time between applications, I don't
think it matters if it's light or dark.

Remember that most fertilizers are added to the water (instead of that
slow-release stakes you plant near the roots). That means that the amount
of water flowing through that plant must contain enough of each nutrient
to keep it healthy.

HTH,
Laie Techie