Staggered lighting intensity suggestions please...


Lifetime Charter Member
Lifetime Member
Jan 24, 2005
Geneva, Switzerland
I'd like to try the method of having higher intensity light for part of the photoperiod and lower for the the rest.

I have a lighting unit with 4x 39w T5 bulbs set up in two pairs so each 2x 39w can be turned on seperately. This over a 200l (53g) tank.

Currently my light schedule is on at 15:30 and off at 00:30 for 9 hours total at 4x 39w or 3wpg. I don't want to cut the light intensity too drastically so was thinking of the following:

14:30 - 16:30 - 2x 39w or about 1.5wpg for 2 hours
16:30 - 22:30 - 4x 39w or about 3wpg for 6 hours
22:30 - 00:30 - back to 2x 39w for 2 hours

- Comments?
- Will I run into a temporary balance problem with the plants by moving to the above schedule?
- Do I need to adjust ferts or will the impact on uptake be unnoticable?

Tom Barr

Staff member
Jan 23, 2005
Re: Staggered lighting intensity suggestions please...

Sounds good,
You can adjust the ferts a little less. Maybe 4/5 as much.

with any light/CO2/nutrient change, give no less than 3 weeks to gauge things, you might see results faster...........but be patient when judging routine changes.

Tom Barr


Prolific Poster
May 15, 2005
SF Bay Area
Re: Staggered lighting intensity suggestions please...

I was doing light staggering on my older 4 WPG tank. I liked the results. The plants grew just as good as leaving all the bulbs on during the photo-period, but only not quite as fast. Less trimming and more relaxing in front of the tank like a lower light tank, but with the extra "punch" of light in the afternoon to put the plants in high gear for a while and encourage the more compact and "nicer" growth you would expect in high light conditions. There may even be algae hindering effects to using this lighting method possibly, but it just a hunch based on my limited observations.

Another aspect I like about the light staggering idea is you can probably get away with longer photo-periods. In my current setup I am able to give the plants what they needed in the afternoon -all 3wpg to put them in high gear and then maybe only leave a 1/4 of the light on just to see the fish in the late evening.