old bulbs not helping corals?

[RaiderFan in NY]

in my t5 setup i have 6x39w bulbs. i changed them once about two years ago. my question is how often should those bulbs be changed? and could the "old" bulbs have any affect on how my corals are NOT growing? or prevent them from growing later?

also, if they should be replaced any suggestions on something that's a little "deeper" looking.

i've only had the coral in there a few weeks and all my water levels are good. although my calcium was a little low the last time i checked. should be better now that i've been dosing .

 

[JustinGr]

I was recently told 18 months max on the life of a bulb, closer to 12 months. Others will chime in.

 

[pcfish]

I wouldn't go longer than 12 months.It definitely effects the growth of corals .Old bulbs are also know to be a contributing factor to nuisance algae. Also what kind of bulbs do you have? Just for reference but this is what I use in my frag tank I have gotten good results with this combo.

ATI True actinic
ATI blue plus
KZ Purple Fiji
GE 6500 k Daylight
ATI Blue plus
ATI True Actinic

 

[b0bab0ey]

I think the mileage on the bulb is the main factor to consider. Someone who is only running their lights 6-8 hrs per day to keep algae under control can go 3-6 months longer than the average hobbyist (10-12 hrs per day). Also, anyone who goes lights out for 3 days per month can add another month onto the lifespan of their bulbs.

 

[divewsharks]

I change mine at 9 months. As mentioned, based on usage the bulbs have a limited useful life. The spectrum will shift (which can lead to nuisance algae) and as well as greatly reduced PAR output. If over a FO tank, not the biggest deal; if over a reef much more of a concern.