Keeping The Lights On?

Hello

Early on in our tank cycling we had the lights on from 08:00 to 22:00.  Yes, why you ask when there's nothing but empty tank to see!  Anyway after a while we got a little green patch on top of the pile of "stone" caves we have that got bigger and deeper green over time.  This I scrubbed off with a brand new nail brush in tank water during a water change.  It got me out on the net to find out what had caused the algal growth in the first place (we have no live plants).  Seems one of the causes was having the lights on too long so I cut it down to 6 hours in the afternoon / evening, 14:00 to 20:00.  The algae came back, I guess because once you get it no amount of scrubbing will get rid of it all.  It isn't so noticeable as before so I'm thinking that the reduced hours has had an effect, plus tank cycling and water changes has reduced the NO3 level a bit.
I have, as usual, been overloaded with topics here and elsewhere concerning when and how long to leave aquarium lights on.  Some say as short a time as possible, 3 - 4 hours once a day.  Others say they have lights on a couple of times during the day.

I understand you need lights if you've got live plants, but do fish require more light than they would get from natural light within a room during daylight hours and normal electric lighting at night?  Is aquarium light only required for human benefit, in that we like to be able to show off our prize possessions?

My daughter and grandson have a small 20L tank with just a couple of small fish in it.  They, the fish not the daughter / grandson, don't like much additional light at all from what they get in their well-lit natural lit kitchen.  It looks like if the tank lights are on (a mixture of white and blue LEDs) the fish start to get a bit nervy.  Under just the blue light they go hyper.

I've seen elsewhere, comments about fish not tolerating additional lighting.  However, at any LFS they seem to have artificial tank lighting on solid during opening hours.  I haven't has yet done any sneaking around out of hours but I suspect they're switched off at night.

We have our lights on a timer that can set any time and duration we might want in 10 minute intervals.  The only downside we have is that when the lights come on they're at full strength after <30 seconds.  The intensity of the lights can be set a four levels + off for white and 2 levels + off for blue.  From a human point of view, we think that 1 white + 2 blue gives a nice effect.  What fish might think of this remains to be seen.  Ideally I would have liked both sets of lights to come on at the level they were when the timer switched them off.

Does anyone have their thoughts on how much, how long for and when we should be using the lighting?

Matt

Yes, your reply has helped.

We don't have any live plants so the plant growth issues don't apply, unless we get some later on.  We've a couple of thoughts about introducing one or two that you can get already growing on bog wood.  Too many other variables to contend with at the moment for us Newbies.

All the other advice in your reply is relevant and confirms my suspicion that the lights are for our benefit not really the fish.

Thanks

I understand you need lights if you've got live plants, but do fish require more light than they would get from natural light within a room during daylight hours and normal electric lighting at night?  Is aquarium light only required for human benefit, in that we like to be able to show off our prize possessions?

My daughter and grandson have a small 20L tank with just a couple of small fish in it.  They, the fish not the daughter / grandson, don't like much additional light at all from what they get in their well-lit natural lit kitchen.  It looks like if the tank lights are on (a mixture of white and blue LEDs) the fish start to get a bit nervy.  Under just the blue light they go hyper.

I've seen elsewhere, comments about fish not tolerating additional lighting. 

Does anyone have their thoughts on how much, how long for and when we should be using the lighting?

In answer to the specific parts of your post quoted above, I kept goldfish for many years without a light as the reaction to putting a light on completely unnerved one of the fish, and I reckoned that he was big, brightly coloured and sufficiently stunning in his own right not to require lighting. When it came to tropical fish, which are a lot smaller than goldfish and thus harder to see, I intended to use lighting but my x-ray tetras were so unnerved by any attempt to put the light on that I gave up. 1.75 years down the line, I decided to make some changes to the tank http://forums.thinkfish.co.uk/general-fishkeeping-advice/possible-changes-to-the-tank-thoughts-welcome/msg30531/#msg30531 and, long story short, have had tank lighting on since the summer and which the fish are fine with (although I think they behave more relaxed and naturally when it's off). You're correct, though, in that they'd be quite happy without it and the lighting is only really for my benefit - it's great being able to see the fish better, though.

The plants, though, have required lighting since I've got them. Anubias and the java moss balls have fared best and would probably be fine without lighting, but the others do require lighting. I've worked out that 7-8 hours per day is about right for the plants I have - anything more seems to be too much. I keep intending to have them on for two separate periods during the day - but keep forgetting to do this!

You are right that the plants will complete for nitrate, this obviously doesnt guarantee that the will be no algea, it might in fact mean that you get a different type of algea instead, but it will of course lessen the chancchances of a significant algae outbreak.  those types of plants you are think about are also pretty indestructible.