When do you dose your fertilizers?

[stream]

I know this is a rudimentary question about fertilization but being the noob that I am, I rather be a fool now then forever.

When do you guys dose your fertilizers in a particular day?

1. Before lights on?
2. Same time as when your lights are on?
3. After lights on?

The logical person in me says either 2 or 3 as thats when plants photosynthesize.

What's your practice?

[Clamence]

I usually dose before lights on but i do not think it will make much of a difference as the nutrient will stay in the water for a long time until they are used by the plant. Hope this helps

[sword28]

I think the followup question will be
"Do plants only use the nutrients during light on?"
During light off, don't plant have to "eat"?
I am thinking of during light off, I dose ferts and the plants can "eat"
so that when light is on, they have energy to "work" to grow?

I also have the same question as to whether is there a best timing to dose ferts? or it really doesn't matter at all?

[Urban Aquaria]

I think the followup question will be
"Do plants only use the nutrients during light on?"
During light off, don't plant have to "eat"?
I am thinking of during light off, I dose ferts and the plants can "eat"
so that when light is on, they have energy to "work" to grow?

I also have the same question as to whether is there a best timing to dose ferts? or it really doesn't matter at all?

I've done nitrate and phosphate tests on my tanks before and after light photo-periods and there are noticeable deceases in those nutrient levels which indicate the plants used up the nutrients (i used to do those tests to work out the optimum nutrient dosing ratios for my tanks)... but when i did the same tests on the tanks again during night time periods (after lights out and just before lights on the next day), the nutrient levels were still around the same.

So my conclusion is during night time, the plants don't utilize nutrients actively, at least not at significant detectable amounts. They do need light to enable the active take-up of nutrients and Co2 to photosynthesize and grow.

It shouldn't be an issue dosing fertilizers during night time period, the nutrients will simply stay in the water until the next day when the plants use it during the active photo-period.

I guess the only danger of dosing fertilizers at night time is if the fertilizer dosages are so high that they may be lethal to fishes and shrimps, so if the plants don't start taking them up quickly, the fertilizers may harm the livestock... though that would be very unlikely unless you are massively overdosing ferts or are keeping super sensitive livestock.

[milk_vanilla]

Before I go work,