[Phdryno]

So I'm knew to this hobby but it is time to replace my year old 150 watt 20,000K metal halide coralife lights. I recently purchased new lights online but I was wondering if it is ok to just replace the old ones or if the new lights would be too brite since everyone in the tank is use to the old dimer lights?

[carym]

No, idea here, so I am tagging along. I have replaced multiple Power Compact bulbs at the same time with no ill effect but I have only had my larger MH setup for about 6 months.

[Jeremy0322]

If i remember correctly you should only replace one light bulb at a time. You will shock the fish if you change all the bulbs at once. Replace one and then wait like a week and then replace the other. That way it is gradual and not this sudden burst of light.

[glampka]

You can replace both at the same time. Just cut back on the time the lights are on & gradually bring them back to the length of time you would normally run them.

[NATIVEVAMAN]

The best plan is to put 3 layers of screen wire between the lights and the water and remove one every 2 or 3 days.The idea is to acclimate the corals to adifferent intensity over time.

[pogodzib]

Originally Posted by NATIVEVAMAN

The best plan is to put 3 layers of screen wire between the lights and the water and remove one every 2 or 3 days.The idea is to acclimate the corals to adifferent intensity over time.

Ditto. You can replace them all at once, since they are shining on different areas of the tank, but you should screen the bulbs at first so that the intensity doesn't jump drastically and harm your corals.

[Phdryno]

Thanks for all the advice. I am going to try the triple screen theory.