Aquatic Plant Forum banner
1 - 20 of 67 Posts

·
Super Moderator
Joined
·
2,785 Posts
Discussion Starter · #1 ·
Hello Folks,

I have brand new data for you on lighting and CO2. It firms up my argument for the Siesta Regimen, that is, to give plants an "afternoon nap".

Below is a figure showing CO2 measurements on my 50 gal tank over the course of a day. The day starts at 7:00 AM when lights come on, so that is TPt 0 (Time Point zero). As you can see, CO2 is rapidly depleted over the next 5 hours. It drops from 5 mg/l at TPt 0 to 2 mg/l at Tpt 5 (Noon). This can only be due to plant photosynthesis.

If I leave lights on continuously all day for 12 hr to 14 hr, CO2 continues to decrease and level off at 1 mg/l and stay there throughout the afternoon. This is not ideal. It means plants are competing for not much CO2 all afternoon. Since algae is better at getting CO2, it gives algae an opening.

However, the Siesta totally changes things. At noon, plants get a 4 hr nap (TPt 5 to TPt 9). Overhead lights are off. Even though this tank is near a window, it looks like window light isn't enough to keep photosynthesis going. So you see a rapid rise in CO2 during "nap time".

When nap is over and lights come back on again at 4:00 PM (TPt 9), the CO2 has bounced back to 4.5 mg/l. This is perfect! Plants now have some CO2 in the afternoon to use for there photosynthesis. As you can see, plants are taking up CO2 almost all afternoon and evening. CO2 decreased from 4.5 mg/l to about 3 mg/l at 9:00 PM (final TPt 14).

The Siesta Regimen is ideal on several levels:

  1. Saves electricity. Lights are on only 10 hr instead of 14 hr (with all my tanks this saves me $6/month)
  2. Gives plants the nice, long photoperiod that they need to do well (I discussed this earlier with documentation; photoperiod should be at least 12 hr)
  3. Fits in with plant physiology and CO2 dynamics (discussed here)
  4. Probably helps with algae control
I repeated the CO2 measurements on 3 other tanks. Same lovely pattern you see here.

I am submitting a full discussion to The Aquatic Gardener for publication next year. However, I wanted APCers to see this new data showing how sweet the Siesta Regimen truly is.

Now, all my tanks (with submerged plants) are on Siesta Regimen.
 

Attachments

·
Registered
Joined
·
2,180 Posts
AWESOME!!! You know, I keep looking at my tanks and not testing for anything, but there's always that little guy in my head telling me something's just not quite right. I remember you mentioning a while back about a siesta period, but I had completely forgotten about it until this post. I've been trying to swap between 10 and 8 hour photoperiods with differing intensities to see if I can improve my plant vigor.

Thanks for the reminder, but especially for the actual data to back it up. I guess it goes without saying what I'll be doing on my lunch break this afternoon with the timers, though I'll leave the emmersed "Wetland" as is.
 

·
Registered
Joined
·
373 Posts
i love the idea of siesta, but for different reasons. I am not home during the day. It is frustrating that i cant view my plants early in the morning and late at night, even with 12hr photoperiod. Some folks solve this problem by time shifting their tanks, allowing some for early viewing and others for the evening.

BTW, Diana's observations about decling CO2 levels do not apply to tanks with CO2 injection. In fact, I give mine a 4-6hr midday burst of light. I may add a siesta to viewing purposes only. That said, I do concur with Diana's conclusions regarding natural decline in CO2, benefit to reduce mid day lighting when that occurs and the likely connection to algae.

A second BTW is that plants do not necessarily need more than 10hrs of light and certainly not at the same intensity. Many of our aquarium plants are not tropical and come from sub-tropical climate which have an annual variation in photoperiod. For example, dozens of plants we keep are native to SC and elsewhere in the southern US. The amazon sword plant doesnt come from the Amazon. Several Echinodorus originate in southern Brazil/Uruguay/Argentina.
These are the subtropical regions
http://en.wikipedia.org/wiki/File:Subtropics.png
 

·
Registered
Joined
·
641 Posts
Will this postulate, work in this schedule? -

Lights on from 4am to 12 noon
Lights off from 12 noon to 7pm
Lights on from 7pm to 10pm

This will save me on electric bills if it would work similarly as your schedule. Thanks.
 

·
Registered
Joined
·
155 Posts
Great to hear, I have used this concept for a couple years now, mainly because it saves money and good for plants but now we have something more concrete which is great!
 

·
Super Moderator
Joined
·
2,785 Posts
Discussion Starter · #7 ·
Any idea whether this affects the fish, either good or bad (such as disrupting their natural body clock, breeding, etc)?
The Siesta Regimen approximates summer conditions. That's what you want for maximum plant growth.

I have kept my tanks on the Siesta Regimen for at least a year. I have not detected any problems with fish or plants.

However, some fish may need increasing daylength (approach of Spring) to trigger breeding. This is something I'm not an expert on.
 

·
Registered
Joined
·
2,195 Posts
I do that in the summer so the tanks do not overheat. The first year I did this there was significantly less algae in the tanks. This year it did not seem to make much difference to the algae.
On: 6AM - noon
Off: Noon - 4PM
On: 4PM - 9PM

Most tanks are near windows, but in the summer the curtains are closed in another attempt to keep the house (and tanks) cooler. Still bright, but not direct sun.
 

·
Registered
Joined
·
476 Posts
This is great! I love hard data that I can put into action immediately... :D

I've been wondering for a while if there's anything in plant physiology that indicates that an Off-Half-Full transition into and out of the siesta period is better than Off-Full-Off, but clearly that's fine tuning of a valuable technique.

-ObiQuiet
 

·
Registered
Joined
·
596 Posts
I take it that this method isn't meant for pressurized CO2. It would still work with pressurized CO2 I think but, the savings wouldn't be there because the CO would be on for 16 hours. Unless, you run CO2 24/7 or use a PH Controller.
 

·
Registered
Joined
·
19 Posts
I too appreciate your providing this information. I started using this technique last summer with great results. My first thought was that the siesta mimicked nature by providing shade from an overhanging tree. I noticed a definite decline in algae by using the siesta method. In the past I have tried varying light intensity throughout the day with not much benefit that I could tell.
 

·
Super Moderator
Joined
·
2,785 Posts
Discussion Starter · #12 ·
I started using this technique last summer with great results. I noticed a definite decline in algae by using the siesta method. QUOTE]

Thank you for writing.

Isn't it nice when you can both save electricity AND get better results?

The Siesta method is totally natural for fish and plants. The summer sun shines and a few clouds shade the water midday. Then the clouds disperse, the sun comes out, and the plants start cranking up again.
 

·
Registered
Joined
·
641 Posts
What are the benefits of this technique aside from saving on electricity, keeping the tank cooler in the summer afternoon and decreased algae?
 

·
Super Moderator
Joined
·
6,406 Posts
I take it that this method isn't meant for pressurized CO2. It would still work with pressurized CO2 I think but, the savings wouldn't be there because the CO would be on for 16 hours. Unless, you run CO2 24/7 or use a PH Controller.
Yep, I think this is meant for soil tanks without high lights and pressure CO2. Her data says 4.5 ppm CO2, in a high tech tank it is around 30 ppm all time so CO2 isn't the limiting factor with pressurized CO2 systems.
 

·
Registered
Joined
·
21 Posts
Very interesting..I reset all my timers for a longer nap period.

I was wondering if you had tested other nap regimens? Would be even better to have shorter, more frequent siestas in order to provide higher and more consistent CO2 levels throughout the day? This seems very natural and “cloud like”. Or is there some advantage to allowing the CO2 to drop that far?
 

·
Registered
Joined
·
189 Posts
Excellent! Thanks Diana. I'm not so sure about the algae benefits since there are lots of species which grow even in low light. And if algae grow utilizing less CO2, if your tank gets direct or indirect sunlight, won't the algae keep growing during the siesta while the plants are dormant?

That said, getting the same plant growth with four hours less energy expenditure is a no brainer. The timers are switched and the plants will be making zzzzs in about ten minutes. :)

Jim
 

·
Registered
Joined
·
60 Posts
No worries... I was just bein' goofy. I understand wanting to learn and understand more. It's why I frequent so many forums and ask questions myself. I use a siesta period on most of my tanks as well. For the reasons mentioned and it works well with our schedule, that is, being able to view the tanks when we are home.

stu
 

·
Premium Member
Joined
·
4,877 Posts
Wonderful inrformation! I have used a siesta before, but switched to a straight 12 hr period. Now that my main 2 tanks are El Natural, and after seeing your results, I have just set my timer back to the 5-on, 4-off, 5-on daylength.

I talked with mudboots about this and he said he's already seen a good response in his lotus (not hugging the substrate anymore). Neat!
 
1 - 20 of 67 Posts
Top