Thoughts on Photo Period?

[NC AL]

It seems most people run their lights with a photo period of around 8 hours. I am working on setting up a 20 gallon tank in my living room and trying to find a way to have a significantly longer time with the lights on. Looking for input from the plant experts and experienced folks.

My reef tank turns on at 5:45 am and turns off at 10:00pm. In the first 4 hours the light only ramps up from 0% to 30% and something similar the last few hours. My lights are only at higher amounts from noon to 6. I really enjoy this as it allows me to enjoy the tank any time I am in my living room. This is very important to me for long term continuation in the hobby.

So would it be possible to have the lights on the planted tank for about 12 hours? With the first 3hrs and last 3hrs very dim? Obviously I don't want to enable excessive algae growth. However is there more to the photosynthesis and respiration aspect that I am not aware of? I see very little ramping up or ramping down in most planted tank lighting schedules. Is there an issue with a longer ramping up/down period?

Hypothetical lighting plan
9:00am - lights on - and slowly ramp up to 10% over 2 hours
11:00am - 10% - ramp up to 20% in one hour
12:00am - 20% - ramps up to appropriate max light setting in one hour
1:00pm - appropriate max setting - on for 6 hours
7:00pm - ramps down 10% in 1 hour.
8:00pm - 10% - ramps down to 0% over the next 1-2 hours.

 

[Minorhero]

The easiest solution by a LOT is to have multiple smaller photo-periods in the day based on when you are not there. Wake at 5:45am? Then have them on till you leave the room, leave them off until you typically come back etc.

Beyond that it is possible to have your lights on for 12 hours a day regardless of whether its a low tech or high tech tank. You basically just need to play with it doing a lot of trial and error to find the sweet spot for you. I've successfully kept low tech tanks with 12 hour light cycles if they are well planted with low light plants like crypts and keeping the light level at 15 ppfd at substrate. In tanks with not enough medium to faster growing plants.... algae took over. In tanks with plants that needed more light.... algae took over. Soooo its tricky which is why people recommend 8 hour light cycles.

If it's a high tech tank you can get away with slightly stronger light at around 25 ppfd.

Use a par meter or the photone app with diffuser to figure out ppfd. Good luck!

 

[JuJuFish]

I have my lights on a similar schedule. Low tech, no injected CO2. I really enjoy the tank when the lights are low.

 

[NC AL]

The easiest solution by a LOT is to have multiple smaller photo-periods in the day based on when you are not there. Wake at 5:45am? Then have them on till you leave the room, leave them off until you typically come back etc.

Beyond that it is possible to have your lights on for 12 hours a day regardless of whether its a low tech or high tech tank. You basically just need to play with it doing a lot of trial and error to find the sweet spot for you. I've successfully kept low tech tanks with 12 hour light cycles if they are well planted with low light plants like crypts and keeping the light level at 15 ppfd at substrate. In tanks with not enough medium to faster growing plants.... algae took over. In tanks with plants that needed more light.... algae took over. Soooo its tricky which is why people recommend 8 hour light cycles.

If it's a high tech tank you can get away with slightly stronger light at around 25 ppfd.

Use a par meter or the photone app with diffuser to figure out ppfd. Good luck!

It will be CO2 injected, but doubtful it will have high lighting. Plants will be average plants. Ones that I have been successfully growing and like the aesthetics of.

Planned plants include:

• Hygrophila Corymbosa 'Compacta'​

• Alternanthera reineckii​

• Ludwigia Repens​

• Some time of carpeting plant​

• Perhaps water sprite or wisteria to help control nutrients

 

[NC AL]

I have my lights on a similar schedule. Low tech, no injected CO2. I really enjoy the tank when the lights are low.

I think I will too. I don't need much I just something to see the fish swim around.

 

[ample]

The easiest solution by a LOT is to have multiple smaller photo-periods in the day based on when you are not there

Doesn't CO2 injection complicate this? It’s probably possible but dialing in two separate photo periods sounds tricky.

 

[ample]

I was just having the exact thought this morning. Unfortunately my Chihiros light doesn't offer that much granularity in the programming. Just a bilateral ramp up ramp down from 0 to the set maximum. I really like your idea of a long ramp up to just 10-20%. I know the Chihiros community has tons of open source code for running custom settings off of a computer or raspberry pi, so I’ll try to look into that.

 

[Koan]

My lights are only at higher amounts from noon to 6. I really enjoy this as it allows me to enjoy the tank any time I am in my living room. This is very important to me for long term continuation in the hobby

Same, plus my tanks are in the TV room so they need to be low light but still visible later in the evening, to watch the shrimps run around

So far this schedule hasn't given me algae problems

 

[Minorhero]

It will be CO2 injected, but doubtful it will have high lighting. Plants will be average plants. Ones that I have been successfully growing and like the aesthetics of.

Planned plants include:

• Hygrophila Corymbosa 'Compacta'​

• Alternanthera reineckii​

• Ludwigia Repens​

• Some time of carpeting plant​

• Perhaps water sprite or wisteria to help control nutrients

If your carpet can take lower light levels, like hair grass. Then you shouldn't have an issue. Monte carlo would suffer. Still more tricky than easy mode 8 hour cycle but if willing to play with it it's doable.

 

[Minorhero]

Doesn't CO2 injection complicate this? It’s probably possible but dialing in two separate photo periods sounds tricky.

Easiest option is to turn on CO2 in the morning and leave it on all day. Just reduce CO2 so you are not riding the razor edge of gassing your fish to death. With reduced light you don't need a lot of CO2.