The Lights Out Siesta Theory

[kenneth_kpe]

The siesta (or lights out time) is something that people do to help combat against algae, well as far as i have researched before, algae apparently doesn't like these so called sudden bursts of darkness in the middle of the day... after thinking about it a little bit i came to a theory.. i was thinking that this did work because when the tank experiences lights out co2 accumulates in the tank, and when it does go on again, the tank has a significantly(in theory significantly) higher ppm of co2 thus encouraging plant growth ! and discouraging the algae to grow..

having said so the algae doesnt grow not because it doesn't like the lights out period, but because the plants benefit from it and in turn outcompeting the algae...

what do you guys think ? is there sombody out there with an accurate PH meter and a heck of a lot of time to test this theory out ? hehehe

 

[B2k2]

I think you theory is totally correct. I have been using the siesta period of 5 on 2 off 5 on and had a lot of algae from the start. The siesta did not seem to stop the algae but when the plants took off the algae has been significantly reduced. I tried one day without the siesta and noticed my PH rise from 6.8 in the morning to 7.6 in the evening. obviously this can not be good for my fish so I started using the siesta again. My tank stays at a stable PH of 7.0, the plants are growing well and have very small traces of algae. My SAE, otos and shrimp are obviously controlling algae aswell but the amount of hair algae I had was ridiculous.

 

[oldwhitewood]

I have just started running my tank without a seista, well I have backed it off so the lights are only off for 1 hour now, this week I am going to change it so they are on all the time and see what happens. I think its a outdated concept now, if you think about it hair algae is caused by not light but nutrient imbalance, keeping alage at bay is more a case of stem plants, keeping your nitrates and phosphates in accordance with the EI method, plenty of light and ~30ppm of CO2, partner that with shrimp and ottos and you have a pretty strong tank there, admittedly it works best for high light tanks but it's a system that works and currently I think it's the most effective method.

There is some thought towards having a graduated lighting shedule, where you have a burst of full on lights in the midday period with dawn and dusk lights on either side, that interests me a great deal but I haven't put it into practice yet.

 

[zig]

Another theory could be that by switching your lights off after 5 hours you are interupting not only the growth of the algae but of the plants as well, and surely this is self defeating if the idea is that the plants outgrow the algae, if you continually interupt the photosynthesis process of the plants how can this help combat algae?

This is an old idea invented by Dennerle back in the late 1980s early 1990s as oldwhitewood has said algae is caused by nutrient or co2 imbalances, and will not be helped or hindered by switching your lights off for 2 hours during the day, if you have an imbalance you are going to get algae anyway until you correct it.

The idea was then given credence by the fact that it was published as being fact (without any scientific backup) in a well regarded aquatic plant book published somtime in the 1990s, the name of which i cannot remember right now (it wil come to me) but i have no doubt somebody will quote the said passage from that book to back up claim that the siesta period works.

But of course its a good idea to reduce your lighting if you have algae in your tank, this would be the first step i would encourage people to do, but you must fix the underlying cause or you will continue to get algae regardless of how ofton you switch the lights off.

I run my lights 10 hours straight, the noon burst theory would have much more effect and credibility in my opinion but i do not have the ability to do this with my current lighting setup.

But at the end of the day the best way to combat algae is to provide enough nutrients and co2, if these are optimal so will the growth of the plants.

 

[oldwhitewood]

Dennerle would maintain you do absolutely have to have a seista, I've read their guidebook and materials a lot and find them to be a bit arrogant, one quote I remember is "if you do have alage it is even fair to say it is your fault", I mean you just don't want to hear that if you're having algae problems! I know I don't. The more I think about it the more it doesn't make sense to me.

 

[George Farmer]

I works for me. That's all I know. The rest is pure speculation.

I have experimented with various photoperiods with various siestas from 4-4-4 to 12 straight. I find 5-2-5 gives me the best results with an ideal growth/non-algae ratio, most suitable for my tank's requirements.

I assume there are many contributing factors as to why this method works, as we all know the planted tank is a complex thing full of many processes that we will probably never understand fully. I still don't fully understand what keeps algae away in the first place!

The other book that is mentioned is Peter Hiscock's Encyclopedia of Aquarium Plants. He just basically re-iterates Dennerle's claims.

The idea of peaking light intensity in the middle of the day is appealing and is the most modern method of planted tank lighting. Dimmable fluorescents are more commonplace now (as always though the UK is behind!) and these would be ideal to test this theory.

 

[emo]

I use the 5-2-5 method for mine and algae is pretty much non existant. But I shall see when I re-do it soon with less fast growing plants.

It would be interesting if someone had the time, money and effort to build 2 identical tanks and run one on 12 straight, one on 5-2-5.

 

[kenneth_kpe]

yeah, somebody might be able to test this on a nano level....

i use the siesta period too but not too combat algae but to combat the heat !! i think the algae fighting attribute is a bonus...... What are those dimmable lights called ? im interested to get one of those because i cant stand the shock that the fishes encounter everytime all of the lights suddenly turn on... its more for the fish really and not for the plants, im still a bit doubfull if sudden bursts of light is in any way detrimental to plants... but i guess the varying photo intensity over the span of a day might be beneficial..

 

[blue_ram]

yeah, somebody might be able to test this on a nano level....

i use the siesta period too but not too combat algae but to combat the heat !! i think the algae fighting attribute is a bonus......

Me too. In summer months, the water temperature gets to be about 90 degrees. Wet-dry filters work wonders in reducing the temperature, but it also significantly reduces the CO2 level as well. Blowing fan over the open aquarium helps too, but open hood usually results in crispy fish on the floor. Can't win... Siesta period never worked for me. I guess as others have pointed out, the underlying problem needs to be addressed.

What are those dimmable lights called ? im interested to get one of those because i cant stand the shock that the fishes encounter everytime all of the lights suddenly turn on... its more for the fish really and not for the plants, im still a bit doubfull if sudden bursts of light is in any way detrimental to plants... but i guess the varying photo intensity over the span of a day might be beneficial..

It's called dimmable fluorescent around here. You need the dimmable electronic ballast (no magnetic) for it to work. So you need T-8 lamps or smaller. It can get fairly dim; I think many have minimal luminescence level of 20% of it's max.

 

[Walt]

I run 5-2-5, and have had great success...
Im not gonna mess around with this anytmie soon

 

[superjalami30]

Heya guys n gals.

I run a siesta and graduated lighting period in one of my tanks.

One set of lights turn on at 6 AM, the second set turns on at 9 AM.
Then at noon the first set turns off for 1 hour, followed by second set turning off at 12:30 for 2 1/2 hours.

At 7 PM the first set turns off, leaving the second set lighting the tank for two more hours by itself.

My "dark" time in the middle of the day only ends up being 1/2 hour, but having just the one set on for 2 hours during the middle of the day seems to be working for me.

I'm sure everything above is nearly completely non understandable.

 

[pseud]

I'm with Walt on this one.

I heard the theory that a lights out siesta prevents algae breakout, thought I'd go with it. At the very least it would cut my electricity bill some

But it seems to be working, I haven't suffered any alage problems! (well, had a minor amount of algae on some Sags due to lack of phosphate, but it was negligible)