light break in middle of day?

and a timer wouldn't work because?

Yeah, I would use a timer. Just set it to turn on later in the day. I had mine set to turn on around 11am because my roommate didn't get up until then. I don't think it will bother your fish. If you set it to turn on around noon and leave it on for 9 hours you will still get to enjoy the tank with the lights on for a couple hours when you get home. You can also buy Blue LED moonlights so you can enjoy your tank while the fish are tricked into thinking it is dark out.

Not to hijack your post sloshy but I have been doing a split shift with the lights from the getgo. i turn the lights on at 7.30 , get someone to turn them out at 2.00.then the lights go back on at 5.30 for around 2 to 3 hours.

Is this stressful for the fish?
what about the plants?

thanks.

sorry to intrude but sloshy's question makes me want to ask about my lighting set-up: 6 hrs in the am (5 to 11) then another 6hrs in the evening (5 to 11) I have been doing this for a couple of days because if the weather (it's hot during the day!!!)
Do you thing there is a problem with this way ?

I am not sure if breaking up the lighting schedule will have adverse and stressful effects on the plants and fish. Hopefully someone with more knowledge about plants will respond.

it will not have much affect on the plants and if you use diy co2, it will allow the co2 to build up some while the light is off. But it can affect the livestock in two ways:

1) for those without automatic ph/co2 control it will mean more ph swings which can cause stress to fish

2) if the room is dark, it will cause additional stress. Fish do not have eyelid, if you all of sudden shine a 200 watt light directly on top of a dark tank. The fish will get stressed and hit the tank walls etc. So by turning light on or off more often, it will affect the fish more times as well. Of course if your room is well lid then that's fine.

On an unrelated note you should never turn on those high powered aquarium lights suddenly from a completely dark room/tank, always lid up the room first before turn them on and consequently dont turn off all the lights at once either.


Other than that, not much difference if you leave it on for 10 hrs, or turn it on for 5, off 5, then on 5...etc..

gagaliya said:

1) for those without automatic ph/co2 control it will mean more ph swings which can cause stress to fish

Click to expand...

I didnt get this part.

Thankyou for your response.

new2tanks said:

I didnt get this part.

Thankyou for your response.

Click to expand...

with a high co2 concentration, it will lower the ph of the tank. When the lights are off, plants stop photosynthesis which means they stop absorbing co2, so the concentration builds up, and ph drops. When the light comes back on, plants resume absorbing co2, so the ph raises again. Hence a constant ph swing that will stress the fish.

This can be avoid as someone said by having a powerhead on a opposite timer as the light, so it creates surface movement for co2 to escape and balance out the tank when lights are off. You can also dump some crushed coral in the canister filtre as a permanent buffer to reduce ph swing, if your water's KH is low (<3).