New Lights and unexpected results

[darrowj]

About 1 week ago I got a new set of lights for my tank. I have a 46 G bow front. I used to have 155 W of CF 50/50. Now I have a 150 W MH and 2 95 W Actinic. I have the two Actinics timed to run 12 hours a day. The MH I have timed to run only 8 hours in the middle of the day.

With that said I have a number of soft corals and a Rose BTA. The BTA seems fine but the corals all appear to have shrunk and withdrawn.

Water parameters have not changed since I put the light in place. So I can only assume the light is the reason for the change.

Is there normally an adjustment period after an increase in light?

 

[Joel A]

yes, you probably should have adjusted your corals to the new more intense light.

Usually people either start with the new MH very high up (12" or maybe a little more) above the tank, and every other day or so, lower in .5" or so.. until desired height is reached.

Another way people do it sometimes is to stack a number of screens or glass tops on top of the tank, to make it so less light makes it through, and every couple of days you remove a top or screen.

 

[Jennifer]

Yup , you need to acclimate corals when switching to more intense lighting. Use plastic window screening built up in layers (at least 3 ) on the top of the tank. Over a couple of weeks start removing the layers till there is none left. Or raise the light as Joel suggested and slowly lower over a couple of weeks.

edit: I could have saved my self some typing if I had read Joel's complete response.

 

[Sherri]

Also, I am changing my bulbs and have changed two -- will wait for a couple of weeks and then change the other three. Always have to do things slowly.

 

[alpha0r]

Your corals are definatly suffering from light shock. Even when I replace my MH bulb I go down to about 4hr a day and add an hour every day or two until I get back up to my normal photoperiod. You could do the same thing but proably go even slower.

 

[Jim Tansey]

When I changed over I did not bother with the screen stuff but just adjusted the photo period over about ten days, worked fine.

Jim