# How long do Giesseman T5 bulbs last?



## fishstein (Dec 12, 2005)

Any idea? I'm about to order 4 4ft bulbs for a new 125H g 60 x 18 x 24H tank and was wondering if I should order 1-2 spares, or just wait until one blows out.


----------



## AaronT (Apr 26, 2004)

They will last two years if driven with proper T5 specific ballasts. I have had mine for 18 months now and they're still going strong.


----------



## fishstein (Dec 12, 2005)

With Advance ballasts, which are high quality programmed start ballasts that are easy on the bulbs and that drive the bulbs at HO levels, not the very hot VHO levels of Icecap ballasts, do you think I need a few 3 in. fans in the back of my canopy? 

With these bulbs, do you just replace your bulbs when your bulbs start flickering or stop working?


----------



## dapellegrini (Jan 18, 2007)

I replace mine every 9 months or so. T5HO's are overdriven and I have seen dramatically more light and better color when replacing 9-month old bulbs (run 8-10 hours a day) with new ones. This goes for 2 Tek fixtures (4ft and 2ft) and a T5HO Catalina hood that I used to run.

Perhaps T5NO bulbs and fixtures have a longer life (but I believe Giessemann only makes T5HO bulbs)


----------



## fishstein (Dec 12, 2005)

Thanks dapaellegrini. however, this in large measure also depends on the ballasts you are using. With the same bulbs, Icecap ballasts will overdrive them and Advance ballasts will not - both however are programmed start electronic ballasts which are much better than workhorse ballasts and other non-programmed start ballasts. The Advance ballasts just run the bulbs cooler than Icecap, which would mean you could run the bulbs much longer. Fans should also prolong bulb life, I'm just not sure if I really need them with Advance ballasts.

Is there anyone out there that has run T5 bulbs with Advance ballasts and can comment on whether or not fans should be used?


----------



## AaronT (Apr 26, 2004)

fishstein said:


> With Advance ballasts, which are high quality programmed start ballasts that are easy on the bulbs and that drive the bulbs at HO levels, not the very hot VHO levels of Icecap ballasts, do you think I need a few 3 in. fans in the back of my canopy?
> 
> With these bulbs, do you just replace your bulbs when your bulbs start flickering or stop working?


Once the bulbs start flickering or stop working their brightness is greatly diminished. It's best just to replace them every 18 months - 24 months. You'll notice the difference when you put the new bulbs in. 

Fans on the electronics can only help prolong the life of the bulbs IMO. Are they necessary? Probably not, but they'll certainly help especially if the canopy doesn't have any sort of venting system for natural air exchange to occur.


----------



## dapellegrini (Jan 18, 2007)

It sounds like you guys both know more than I do on the subject - I am interested to know why my T5's don't last as long as yours. 

It is fairly common consensus in our local group that T5's go for about 9 months. They don't burn out or flicker, it is just that their light output is significantly diminished at that point. Which ballasts are used in the Tek fixtures? Mine run very cool with no fans... Perhaps changing the ballasts will extend the effective life of my bulbs? Getting twice the mileage on my bulbs would save quite a bit of money over a few years.

Hope I am not dragging this off topic too far...


----------



## AaronT (Apr 26, 2004)

dapellegrini said:


> It sounds like you guys both know more than I do on the subject - I am interested to know why my T5's don't last as long as yours.
> 
> It is fairly common consensus in our local group that T5's go for about 9 months. They don't burn out or flicker, it is just that their light output is significantly diminished at that point. Which ballasts are used in the Tek fixtures? Mine run very cool with no fans... Perhaps changing the ballasts will extend the effective life of my bulbs? Getting twice the mileage on my bulbs would save quite a bit of money over a few years.
> 
> Hope I am not dragging this off topic too far...


What I know on the subject is mostly just experience. I have a 4 x 54 watt Tek fixture and another 4 x 39 watt fixture with DIY IceCap SLR reflectors and T5HO ballasts from ballastwise.com. I'm not sure which ballast is in the Tek fixture.

I've had the same bulbs in the Tek fixture for just over 2 years now. They're due to be replaced any day now, but the plants are still growing okay with them. The bulbs in the DIY fixture are 18 months old and still going strong. Neither fixture has fans.

I'm using Phillips Daylight bulbs in the Tek fixture and Giesseman Middays in the DIY fixture.

I also am only running a 10 hour photo period with noon bursting for 5 hours in the middle of the day with two bulbs. Once a year is up I switch which two bulbs are on which bank so they burn the same amount of time before being replaced.


----------



## dapellegrini (Jan 18, 2007)

Ah thanks Aaron. I notice that my bulbs loose about 50% of their brightness in the first 9 months, but they will keep growing plants (depending on what is in your tank and how much total light you have to start with) well beyond that. Not sure how the PAR is effected.

I notice much better growth with new bulbs though (faster pearling, etc). Not that Lux measurement means anything to plants, but I have measured that on the last set of bulbs I replaced and it was about 50% of the new bulbs after 9 months.

A number of the local folks here in AZ that run these Tek fixtures also report similar findings - better to replace every 9-12 months for optimum growth, etc.

Good idea about switching the bulbs to extend the over all life - don't know why I didn't think of that! I run 8hours total with a 3 hour burst from the 4th to the 7th hour. 

The Tek fixtures have no fans and stay cool to the touch.

My old Catalina hood was burning hot to the touch and that was with a big fan. I think they used Workhorse ballasts in those


----------



## freydo (Jan 7, 2006)

50% light loss after 9 months? yeah... the over-driving is causing the lamps to lose their light output. or at least a cause.

i've been using mine for over a year with fulham workhorse 5 ballasts, and light output loss is not very noticable. but i did purchase 2 extra when they do burn out, which is when i'll be replacing. they're just too expensive to replace otherwise. of course, i've got individual reflectors,which helps with the light output.


----------



## dapellegrini (Jan 18, 2007)

I have been told by many different people (going on what others are telling me here) that bulbs loose their effectiveness well before the actually burn out. Is this no longer the case? 

I bet if you swapped your 2 new bulbs in you would see a significant difference (if we are still taking about T5HO).


----------



## freydo (Jan 7, 2006)

i'm sure there would be a difference, and yes, they do lose the intensity when they were new. however, after a year, mine are still providing sufficient lighting my high-light plants require. for me, that's good enough.

you can use a light meter to measure the actual light out put, but that's just numbers. how are your plants growing? that's the best indicator IMO. you can replace the bulbs if it makes you feel better, however you "might" be just throwing your money away to replace bulbs that would still do the job.


----------



## dapellegrini (Jan 18, 2007)

From a quick google - it looks like Tek fixtures use Advance Ballasts. If it is any help, my 24inch Tek (4x 24w) stay room temp with no fans (can't find a warm spot on it - aside from the bulbs themselves) and my 48inch Tek (4x 54w) is warm at most - also with no fans. Certainly not a lot of heat from these things. I would be surprised if you need a fan to cool them.

I should perhaps start offering up my 9-month used T5HO's for sale - perhaps there is a market


----------



## fishstein (Dec 12, 2005)

It's up to you whether or not you want to replace bulbs when their visible light output seems to be lower - but keep in mind as freydo pointed out that you might be spending on something you just don't need. I've run high quality T8 plant bulbs for 2 years straight with highly reflective mylar in the hood (and later DIY aluminum reflectors like the Tek II reflectors) and I was getting enough light from 4 48 in. T8 bulbs over a 75 gallon to grow just about anything. I traded tons of nice plants from that tank.

A lot of people told me I'd need more wattage, but they were wrong. A lot told me to replace the bulbs, but I found this unnecessary. Reflectors push more light into your tank, keeping your water clear (good filtration, surface skimming and water changes) helps more light get into your tank and keeping the tank cover clear (if you use one) allows more light to pass through.

In my opinion, as many people as possible in the hobby should use reflectors (simple DIY mylar or purchase high quality parabolic) to increase their light rather than add more bulbs - better for your pocket in the long run (less bulbs, less electricity, lower A/C needs) and better for the environment. A lot of us should also think about minimizing water changes through better use of fertilizers to match tank needs and better consideration of bioload. Wars have [and are being] fought over energy and clean water. I'm not saying we should give up our hobby, just do our part to minimize its impact. OK, stepping down from the podium...

I'm not surprised the Tek fixtures use Advance ballasts - that makes sense. Very encouraging on the low heat output.

BTW, I picked up my retrofit kits at a great price from an LFS that ordered them for a customer who never picked them up (my guess is as a reefer he probably went metal halide, which gives more of a shimmer effect). They originally came with Workhorse ballasts but the LFS misprinted the sale ad and wrote "Icecap" instead. So they felt obligated to make good and were going to give me Icecap ballasts free of charge, and I told them I'd take Advance ballasts if they had them. Why? Because this tank is in a place that's relatively warm over the summer (SF Bay Area) and I'd like to use a good programmed start electronic ballast but not overdrive the bulbs and produce a lot of excess heat and burn the bulbs out early. I know that 4 T5 54W bulbs with Tek II reflectors, which push TONS of extra light down into your tank will be more than sufficient to grow nice plants without overdriving them. I factor economy and utility into any buy/build decision.

I may still use 1-2 fans, 3 or 4 in., one on either side of the back of the hood, to keep the tank from overheating on hot days when A/C is not being run. We only need to run A/C for a few hours a day in the middle of the hottest part of the afternoon on the sunniest warmest summer days.

Anyone have any tips on the QUIETEST 3 and 4 in. fans that can be run directly from wall outlets (so they can be plugged into timers)?


----------



## dapellegrini (Jan 18, 2007)

Ya - I upgraded from a 6x 54w Catalina fixture to a 4x 54w Tek fixture and get about the same light into my tank - maybe more. I can also run the light for less time overall, with only a 3 hour blast over both a 120-P. You are correct about the reflectors - they make all the difference.

Though - I wonder if perhaps running less total light over your tank leaves you with a smaller margin for the diminishing output of the bulbs? 

Good luck with your setup. Would you consider a chiller? How hot will the house get in the summer?


----------



## fishstein (Dec 12, 2005)

Thanks, going to need it. So hard to find the time to finally pull all the pieces together, been knocking a little off at a time. Nearly finalized my list of remaining items to order for it, but still thinking about layout (and looking for good driftwood sources) and plants.

I'd hate to have to spend more on a chiller, which I think would run you at least a few hundred dollars. After speaking with a few reefheads and a marine lighting place, seems like I'll be fine running 2 small fans blowing in from the back with some venting at the top (which I plan to cover with a little 90 degree vent so that light doesn't shine up on the ceiling). I'd be fine without, but the fans will make sure the tank doesn't get too hot on warmer days.

The shop recommended auto-adjusting variable speed fans which speed up when it gets warmer - still researching those. They are about $10 more than non-auto fans.


----------

