clam gone

[Galvan]

I have/had the coralife Florescent lighting about 210 watts for 2 years. My tank is 75 gallon 80lbs LR and this is the light I have had for 2 years. My clam to me has died as it is no longer protruding out the sides of the shell. It is open a 1//4 inch and I can see in the inside there is very little animal inside. Can I remove it or should I wait longer to see if it comes back.
Just this weekend I received T5 lighting at 460 watts. I have other corals in the tank and acclimating them to the new light. I have solar window screen on the top of my glass top to not introduce to much light to the tank. About how long should I keep the solar screen on the tank before giving the tank the full dose of light?

 

[BillOlson]

You should replace your lights every 12 months. The UV that comes off of them is burnt out around a year and no longer provides your coral with anything beneficial...

 

[mr_X]

i would just lift the fixture higher, using some 2x4's or something on the sides for a week or so, and then slowly remove the 2x4's until it's sitting flush with the tank. i don't think you are acclimating the corals by blocking the light, because when you remove the "solar window screen" it will be their first day under the T5 anyway.
i also agree with bill. bulbs wear out and should be replaced regularly. i think less than a year actually. 9 months for me.

 

[IslandCrow]

I'm pretty sure florescent lights do not produce UV radiation. I believe what BillOlson is getting at is that as lights age, along with losing PAR, their spectrum starts to shift further to the red side of the spectrum. This happens well before they actually burn out, and the shift is subtle, so you usually don't notice it. As far as how often to replace them, that varies. I believe it's about 6-8 months for PCs, but T5s are supposed to last at least a year.

What type of clam are we talking about by the way? If you could post a picture, that would help, but from what you're saying, it's unlikely this clam will survive. Still, I personally would just monitor my ammonia and nitrate levels closely and leave it in there. Never say never, right? Unless it's a very big clam, I don't see it fouling the water in a 75g very quickly. Of course, keep up with your water changes.

As for acclimating to the new lights, I take it solar screen is different from regular window screen, and I'm afraid I'm not familiar with what you're talking about there. Most people use multiple layers of normal window screen and remove one layer per week. Slowly lowering the lights isn't a bad option either, but if that's a T5 unit with individual reflectors, that's a huge upgrade, so you'd have to get the light up pretty high. I'd take at least a month to acclimate the tank to the new lighting.

A couple other things you can do to acclimate is start off not firing all of the bulbs (I'm not sure what fixture you have, so I don't know how much control you have over that) or reducing the photo period and slowly increasing it over the course of the month. You can also use combinations of these methods. Keep an eye on the reactions of your corals, especially soft corals. If they're not opening completely or even looking a little shriveled, that's often times an indicator you're going too fast.