Lighting Timer Question

[vidiots]

Hello,
I've just setup my new 180gal 6ftx2ftx2ft plant tank. I went all out with this one. I've got pressurized CO2, automatic water changer, dosing pumps etc. Now I'm not sure what the best settings for my light timers should be. I now have the ability to do something new and that is stagger the lighting throughout the day for the sunrise/sunset effect.

For lighting I have a combo MH and PC fixture from Hamilton Technologies. The fixture is 6ft long (same as the tank). It has a mirror finish reflector. It has 4 power cords that are pluged into seperate timers, and is suspended from the ceiling about 12inches above the tank's glass top.

The first power cord controls 2 65watt PC bulbs located on the rear lefthand side of the fixture.
The second power cord controls 2 65watt PC bulbs located on the front right hand side of the fixture.
The 3rd power cord controls 2 175 watt MH bulbs located left and right side of the fixture and the cooling fans.
The 4th power cord controls 1 175watt MH bulb located in the center of the fixture.

Now here is what I've been considering. Setting the 2 175watt MH bulbs to come on for 8hrs during the middle of the day, with the third 175watt bulb to come on for 6hrs approx an hour later and turning off an hour before the other two. I would have one of the sets of PC bulbs come on about 2hours before the 2 MH bulbs and turn off 1 hour after they turn off. I would also have the other 2 PC bulbs come on 1 hour before the 2 MH bulbs and turn off 2 hours after.

So if I figured this out right I would have:

9:30am - 10:30am = 0.7 watts per gal (130watts total)
10:30am - 11:30am = 1.4 watts per gal (260watts total)
11:30am - 12:30pm = 3.4 watts per gal (610watts total)
12:30pm - 6:30pm = 4.4 watts per gal (785watts total)
6:30pm - 7:30pm = 3.4 watts per gal (610watts total)
7:30pm - 8:30pm = 1.4 watts per gal (260watts total)
8:30pm - 9:30pm = 0.7 watts per gal (130watts total)

9:30pm to 9:30am = 0 watts per gal (12hrs of night). There would probably be about 4hrs during this time where the tank would receive ambient room light, but it should still get about 8hours of complete darkness.

Does this sound reasonable or would a different arrangement be better? Ideally, I would like some light on until at least 9:30pm so that I can check things out and feed the fish when I get home from work, and have the lights come on as early in the day as possible so that I can see to to maintenance on the weekends without having to wait til later in the day to be able to see what I'm doing.

 

[Tom Barr]

Re: Lighting Timer Question

I'd suggest lots of light in the eariler part of the day, say most at about 2 hours or so in for 3 hours or so, then back it off.

Try 10 hours total and start the light at 12 noon till 10pm.

Regards,
Tom Barr

 

[yme]

Re: Lighting Timer Question

hi tom,

do you get significantly better results with a light peak in the earlier parts of the peak. my light cycles is 10 hours, but a light peak of 3 hours from 19.00-22.00. just because I am home at that time. Would an earlier light peak result in better growth?

greets,

yme

 

[vidiots]

Re: Lighting Timer Question

Just checking to make sure I understood what you were suggesting. You suggest that I move my brightest lighting period to 2 hours after lights on and for a duration of only 3 hours instead of 6 hours. And you also suggest that I shorten the total tank daylight time to 10hrs instead of 12hrs.

The part of moving the brightest part to the beginning of the day makes good sense to me. I was planning on having the automatic water changer run then the dosing pump run just prior to lights on, figuring that this would ensure that the plants had optimal conditions when the lighting period starts with minimal excess during the dark period.

The part about shorting the bright light period that drasticly puzzles me a bit. Just seems like it would be too short. Any chance you can expand on this part? I will rely on your wisdom for this, as it is my first high light tank.

Would there be much harm in extending length of the dim light period, or will that cause me more trouble than its worth?

Thank you very much for the advise!

 

[Tom Barr]

Re: Lighting Timer Question

Yme might do better to have most all the lights on for 10 hours, you can do well with 10 hours as well, but with all the MH's, you might want to run them 3 hours or so a bit more in the eariler part.

The amount of CO2 is typically pretty decent then, and then you have a high level of O2/pearling for the rest of the day when you back off the light.

Regards,
Tom Barr

 

[misha]

lighting scedule

It is very good to know how to set up light schedule over 90 gal heavy planted, co2 injected tank. I have 4-96 watts bulbs 6700k that have 2 switches(2 and 2) can be on at separate time. 4- 55 watts 6500k with 2 switches (2 and 2). What I understand that period of respiration is also very important in plant physiology. I don't want to overkill with such a heavy lighting.As a fertilizing method I use EI.
Thank you.

 

[Tom Barr]

Yes, I think the middle of the day works nicely.
You can play around and see.

Some do the high light phase at 2-5 hours in, then back off.
Some do it later in the day, say 5-8 hours in etc.

Those are just some options.
No hard rigid rules here.

Regards,
Tom Barr