you can have light sensor controlled shade cloth, alot of orchid greenhouses use them.

not cheap tho.

what part of a greenhouse is :P compared to heating or cooling a greenhouse they are cheaper, and not really that difficult to setup or to build one, just calibrating when the shade changes can be ticky

What is not cheap any links. Would love some more info.
Thanks

I just read the entire post, especially about putting them under the surface, the company i work for makes underwater lights to light up fish farms and extend day length, the reason we use underwater lights and not surface mounted lights is that the surface of water reflects about 40% of the light unless its directly shining downward but that wouldent light a large area well so we put them under about 10ft and one light lights up a 25X25 area like daylight and those are only 400w with 1000w or 1500w we get about 50X50. so underwater you would get alot more light from a source but you would also get all the heat.

i would have posted on reef central but dont have an account.

very interesting indeed. And you can definitly see the difference in coloration that the corals change when under mh vs solar. I can see this option with a light sensor to activate supplementry lighting as something to be used on a larger more permanent tank setup. Ill be honest though, I have one of my tanks right by the window and early in the morning when the sun hits my frags in it, the open right up and bend towards the sunlight instead of the 150 watt MH sitting 6" above them.

So to say the least, natural sunlight is way better and probably far more intense then most manufactured light systems.

this pops up every 3 to 5 years or so, doesn't work very good, most either reinstall MH for the winter or shut down there tank cuz they fry there corals in the spring. If you read the whole thread they talk about a few people who took them out as the intensity increase in the spring burnt corals, and the owner of the thread shut down his tank cuz of problems with them.. I am trying to think if anyone has run them long tearm and I can think of anyone. to bad as it would save a couple bucks over a few years.

Steve

Then maybe check this guys thread out. It's a very hot item in the Large Tanks forum and he's been doing this for years. Stunning reef and he has ported the sola tubes from his old tank to a new one! He's in Australia I believe and he certainly isn't frying any coral.

http://reefcentral.com/forums/showth...readid=1563053

I ment here in north america where we have a much colder winter. the problem comes from the decrease in sun for 7 or 8 months then the rapid increase in intensity for a while. when you get close to the equator there realy is no change in seasons. hence the closer you get to the equator the more coral reefs there are. we could talk about people in hawai having outdoor tanks with only natural lighting.. the fact is we don't live in hawaii or Austrailia but lets see you do an outside tank is calgary and see how it works out for ya:mrgreen:

Steve

Steve

My bad I thought you meant solar powered in general.

If you could detect this rapid increase and then have some automated way of gradually exposing your reef to it it may work. Have a target par at waters surface equal to all your artificial lighting on at full power. Then detect what the sun provides. If it's greater than your target par have some dimming shields or something slide into the solar tubes and if it's less have your artificial lights ramp up.

It'd require some custom programming and equipment and dimming t5s/mh but that'd be pretty slick.