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Lighting period


14 Sep 2016
Any detrimental effects to fish or plants if I change the lighting period from 8am-5pm to say 3pm to 10pm ?
8am-5pm is 9h, 3 pm-10 pm is 7h. It means your plants will get less light, so you might want to consider 1pm-10pm, if the plant growth was nice with 8am-5pm. If you don't want to stress your fish, you might do this change gradually. Change to 9am-6pm for two weeks, then 10am-7pm and so on. I like to have my lights on 3pm-11pm, this way I can actually see my tanks. Getting back from work to dark tanks is nothing fun.
No. I have them from 1700-0100. Probably needs a bit longer I think.

Was worried that daylight and evening light would be too stressful for fish and cause more algae...
If your tank isn't exactly in front of the window, daylight won't do much so don't worry about it.

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I installed a dimmer/controller and after reading about Plants Compensation Point a light lit up. And since i ran tanks up to 18 hour light periode. With 10 hours at full 100% and the others bellow compensation point. Now 18 hours might be a tad much, bt seeing my pond setup in the garden do it wonderfully with having 18 hours in the summer. It definitively can be done, even at compensation point.

Anyway, bellow compensation point still makes the tank visualy viewable.. It actualy looks quite good with a tranqulizing effect and looks quite natural having a dimmed tank in a dimmed room after dark. :)

At least that is my personal experience with creating such a longer more natural light cycle now looking at it for years already i think my fish like it to. And do not experience more algae.

If you relate it back to tropical conditions at the equator, than 12 hours would be spot on.
Over a few weeks i lost 4 rasboros jumping to light shock so i installed some 1.5w clip on leds on a timmer 1/2 hr before main lights come on and 2hrs before lights go off and the tank looks very nice
There’s a thread on here somewhere with someone with a similar lighting rig to you talking about a pseudo sunrise and sunset achieved by turning the lights on in sequence (east first) then off in reverse. No dimmer, just one by one a few minutes apart. With the dual set of lights you could do the small ones in sequence first, followed by the large. It sound like the fish responded well to it.
Not heard about the compensation point before. I take this to mean that tank lights can be run at a low output before or after the main lighting period with no detrimental affect on... algae?

Interested to find out more!... I will get to Google...
Ok so I see it's the light intensity at which the rate of photosynthesis matches the rate of co2 production. That all makes sense... I run a siesta period in my lighting so co2 levels can rise again mid-day (low tech tank). But I guess an alternative would be to run the lights for say 6 hours then dim them significantly for another 2? 4? 6? hours? How far can you stretch this theory and how would this impact plant and algae growth?

Or am I barking up the wrong tree altogether!?
I run a siesta period in my lighting so co2 levels can rise again mid-day
Inhigh tech, CO2 added tanks general we kinda don't like that. Co2 doesn't seem to build up sufficiently to protect the plant against the photons. We prefer a shorter but constant lighting period.
In low tech tanks it hasn';t proven it's worth either i believe.
When I switched my tanks to low tech I have tried the siesta periods too thinking about optimisation of CO2 then I realised I am going low tech and why should I care.I have better results with constant photo periods with good fertiliser regime and regular tank maintenance. Less algae and decent plant growth. In my tanks only sand as substrate and some light units are too strong so use floaters to dim light.Its about balance.I witnessed it myself as once the balance is achieved the algae dies off in a week and even filter hoses ,stones and glass remain clean for months.Its not easy but is doable.I always start with 4h photoperiod and increase it over months to 8h depending on plant growth .It take more than an year sometimes till I achieve 8h
Its just my opinion and what is working for me
Regards Konsa
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