How long do you wait to replace your t5s.

SaltISlife · Nov 20, 2020

Ive seen the BRS videi and read some google searches on this.. but im still curious to ask it myself. How long do you guys wait. Do you even notice any different in color or coral growth using your old bulbs ?

I ask because my tank is 135 gsllons 72 inchs long. I have a 48 inch and 24 inch fixture to cover the entire length of the tank. Reason 48 and 24 is i already had the 24 for a 60 gallon hexagon. So no point in buying two 36 in h fixtures when i could just get a 48.

Anyway the bukbs in my 24 inch fixture are maybe 6 months old now. The 48 they are probably gosh.. 18 months old now. I honestly am noticing no difference in growth or color on my corals. My acros like the red planet are still red not turning green which is from a lack of light for a red planet. The walt disney and tri color are still the same. So are my 8 other acros. My zoanthids are still growing very well. As are my trumpets and chalices. And favias. I have about 60 corals under the 48 inch fixture.

So im just curious.. should i bother replacing these lights ? Or no ? Lol.. I do notice one side if the tank is darker thsn the other when i first flip the lights on. But once they warm up i see no diff with my eyes anyway

Biglew11 · Nov 20, 2020

The eyes are terrible at noticing a difference in light output. If I remember the brs video correctly, they said you can get away with 18 months or so with no real reduction in par. Maybe a slight shift in color spectrum.

I've recently added kessil a360x to my fixtures, so will probably let the t5 go for 1.5 to 2 years. I run the t5 about 5 hours a day.

ScottB · Nov 28, 2020

I change mine out roughly every year or so. Not sure how much PAR difference there really is. I will check that next summer. I think the point is not to let them go so long that there is a significant change (spectrum & or PAR) when you finally do change them out.

Corals won't react much to the gradual decline, but they can freak out when you pop in all new bulbs from very tired bulbs. Many folks only change out X number of bulbs at a time. I just raise the fixture up 6-8".