Poll: How often do you change bulbs?

BigJohnny · May 2, 2018

radiata said:
Agreed, you should only replace one T5 at a time...

Yea I do one a week until all are replaced. Also, never run fresh carbon when replacing bulbs. Really applies more to metal halide since it's one big bulb and the change is all at ounce, but could still be an issue with t5s.

mike werner · May 2, 2018

BigJohnny said:
Yea I do one a week until all are replaced. Also, never run fresh carbon when replacing bulbs. Really applies more to metal halide since it's one big bulb and the change is all at ounce, but could still be an issue with t5s.

you say 'NEVER run fresh carbon when replacing bulbs"but don't give the reasons for our readers.

BigJohnny · May 3, 2018

mike werner said:
you say 'NEVER run fresh carbon when replacing bulbs"but don't give the reasons for our readers.

SORRY (figured id stick with the all caps theme)

Changing carbon (especially if it's been a while or you don't normally use it) can significantly impact water clarity and therefore light penetration and par. This coupled with the added par of fresh bulbs can result in a significant increase in light that can stress/bleach/damage or even kill a coral.

For example: 15% increase in par from new bulbs + 15% increase in water clarity = 30% more light to your corals. It's just better to stagger that change just like you would do by changing 1 t5 bulb at a time per week, or something similar.

I said never just because it's a good rule to follow and waiting a week or two or doing it a week or two early potentially has minimal impact vs the risk of doing them simultaneously. Sure you could be fine for a variety of reasons, but it can be risky, in my opinion.

I picked up this tip a few years back from melevsreef who changed carbon and halide bulbs (without raising the halides or reducing photoperiod temporarily which made the change even more dramatic) and experienced paling/bleaching of corals.

It really goes back to one of the golden rules of reefing imo, make changes slowly and never change more than one thing at a time.