The Planted Tank Forum banner

Dimmabe LED Setup - Ramp up photoperiod or power?

7K views 16 replies 6 participants last post by  jeffkrol 
#1 ·
I am expecting plants on thursday and am trying to finalize my light settings.

I saw several threads that talked about finding the best photoperiod by starting a bit low and increasing until plants start to close up near the end of the photoperiod. Starting high can apparently lead to algae problems. I am trying to adapt these concepts to my dimmable.

Should I increase the LED power or increase the photoperiod to find the optimal light level?

I have two Kessil A360WE LED pendants on a 24" deep tank. That should be very high light intensity with great penetration at full power. They only dim down to about 40% of output (by Lux measurement out of water at 30"). Aside from human viewing time, are there any other factors I should consider in making this decision?
 
#2 ·
I find it will always be pretty hard to totally avoid algae so allow myself some mistakes along that line. Planning can only get me so far and then I have to adapt it as things progress. And part of that progression will be how the tank and plants change as they grow so I encourage staying a bit flexible in the thinking. A plant that is 4" high at start may feel totally different when it gets taller and has something like a frying pan near the top?
I also like to see my plants so I adjust the light schedule to fit my viewing as long as it also fits for growing the plants. I have no qualms with going for a four hour lights on with time off while I'm less prone to be there and then another lights on period later in the day.
Tough for me to set out a firm schedule for things that are constantly growing/changing themselves. I just use simple timers to turn various light sections on so not much help on the ramping question.
 
#3 ·
Oh, I got that I will need to make adjustments and that I will have algae problems. No illusions there, but I do need somewhere to start. The closer it is, the more likely my first batch of plants will survive. Fortunately, I can mostly work at home (grading exams and papers) for the next few weeks.

I checked the power of the lights using my phone and the power to LUX was linear. I wish I had a waterproof meter to confirm that it is more or less linear underwater. That is my main concern about ramping intensity I think.
 
#4 ·
@PlantedRich conveys my thoughts exactly.

As the plants grow things are ever changing. The most important aspects that help me are light timers and dimmable lights. The timers let me be both exact and consistent from day to day. Once I sort out the duration (photo period) I can just forget about everything and let the timers do all the work. The dimmable function makes it easy to fine tune everything, I start out a new tank with the lights dimmed lower than I expect and then slowly increase them over days/weeks until I see negative effects (algae in most cases). Although as PlantedRich stated, it's usually always changing as your plants grow and plant-load changes. I guess you could always just run your lights lower, but to push that fine line between maximum growth and the negative effects of too much light, you're always tweaking things. Just my thoughts...

Presently all my tanks run on a single 7hr. photo period.
 
#5 ·
Should I increase the LED power or increase the photoperiod to find the optimal light level?
first realize the 2 are related...at least to a certain degree..

1000 photons per hour @ 1 hour is equiv to 500 photons per hour @ 2 hour.

so either works for the most part..
Kessil only dims to 40% seems odd..Most report 10-15% is normal though not sure if they did measurements..

Since it is driven (assuming here a bit) w/ PWM photons should be fairly linear (not to vision but that is another story). Full on at 40%, full on at 50% of the time ect..
 
#10 ·
For reference for anyone considering the Kessil and a controller. The manual dial on the fixture has essentially the same cutoff as the Apex and the cutoff is not affected by which type of outlet on the apex or wall you use to power the light. It looks great on the tank and I like the color of the tuna sun, but not as dimable as the AI fixtures.
 
#14 ·
10 hour photoperiod and ramping intensity from 30% setting it is. The six profiles let it ramp through a sin model diurnal cycle in light intensity (brighter at noon). It wont matter now, but will be more noticeable as the max intensity goes up. Wish it really started from zero. Not quite sure whether to vary color at sunrise sunset given it starts straight at midday intensity.

Here are my programs for now

LED_Left (outlet)
Fallback OFF
Set OFF
If Time 11:00 to 21:00 Then ON
If Temp_S > 84.0 Then OFF
If FeedB 000 Then ON

LED_Right (outlet)
Fallback OFF
Set OFF
If Time 11:00 to 21:00 Then ON
If Temp_S > 84.0 Then OFF
If FeedB 000 Then ON

LED_Color (6_1) (variable speed port)
Fallback Off
Set Off
If Time 11:00 to 12:40 then C_Dawn
If Time 12:41 to 19:20 then C_Day
If Time 19:21 to 21:00 then C_Dusk
If FeedB 000 then C_Day

LED_Intensity (6_2)
Fallback Off
Set Off
If Time 11:00 to 12:40 then I_EarlyMorn
If Time 12:41 to 14:20 then I_MidMorn
If Time 14:21 to 16:00 then I_LateMorn
If Time 16:01 to 17:40 then I_EarlyAft
If Time 17:41 to 19:20 then I_MidAftProfiles
Profile Name: C_Dawn sunrise
Control Type: Ramp
Ramp time (minutes): 100 photoperiod /6
Start intensity: 100 aesthetics
End intensity: 40 aesthetics

Profile Name: C_Day daylight
Control Type: Ramp
Ramp time (minutes): 1 short
Start intensity: 40
End intensity: 40

Profile Name: C_Dusk (sunset)
Control Type: Ramp
Ramp time (minutes): 100
Start intensity: 40
End intensity: 100

==================================

Profile Name: I_EarlyMorning sunrise
Control Type: Ramp
Ramp time (minutes): 100 photoperiod /6
Start intensity: 13 minimum response
End intensity: 22 min + 0.5*range

Profile Name: I_MidMorning
Control Type: Ramp
Ramp time (minutes): 100
Start intensity: 22
End intensity: 28 min + 0.866*range

Profile Name: I_LateMorning
Control Type: Ramp
Ramp time (minutes): 100
Start intensity: 28
End intensity: 30 maximum response

Profile Name: I_EarlyAfternoon
Control Type: Ramp
Ramp time (minutes): 100
Start intensity: 30
End intensity: 28

Profile Name: I_MidAfternoon
Control Type: Ramp
Ramp time (minutes): 100
Start intensity: 28
End intensity: 22

Profile Name: I_LateAfternoon
Control Type: Ramp
Ramp time (minutes): 100
Start intensity: 22
End intensity: 13

Profile Name: I_View
Control Type: Ramp
Ramp time (minutes): 1
Start intensity: 15
End intensity: 15
If Time 19:21 to 21:00 then I_LateAft
If FeedB 000 then I_View
 
#15 ·
Osmosis, if you can control each lamp individually, why not start one up and the let it ramp to full power as quickly as the control allows, then start the 2nd one at that time and when the 2nd lamp ramps up, leave both on for a while and then reverse the process. As a fisherman, I can attest that under the east bank the water is dark until the sun rises over the tree line and then the reverse happens to the west bank. So a sudden 30 or 40% may not be that unusual considering tropical freshwater plants are often surrounded by dense forest and plants may "see" sunlight more suddenly then gradually. Just a thought.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top