Who changes bulbs with a PAR meter?

[H@rry]

I've got 13 MHs and I have been changing out the bulbs every 12 months. Sometimes I think this may be foolish to change a bulb by a calendar. I was wondering if I got a PAR meter and measured my new bulbs as a "base line", then I could measure them every month or so for comparison. I may find that I need to change them more frequently. I also may find that I can run them longer.

I guess what I saying is this sounds like people dosing their tanks with something but never testing for what they're dosing. Does that make sense?

Does anyone test with a PAR meter to determine when bulbs need to be changed?

 

[Sikryd]

Yep I do. I also can tell when a bulb isn't up to "par" too. (pardon the pun ;) )

I just replaced a bulb that must have died quicker than it should of. It was putting out 550 par, when the rest were in the 750's.

Thankfully I have a buddy that has a par meter that I can borrow anytime. Plus both of the local clubs have one that we can "check out", which is nice.

 

[ksc]

I got one this spring for $150 in a group buy, my favorite piece of equipment. You'd be surprised at all the misinformation out there....

 

[litenyaup]

I got one this spring for $150 in a group buy, my favorite piece of equipment. You'd be surprised at all the misinformation out there....

what kind of misinformation?

 

[JNye]

I got one this spring for $150 in a group buy, my favorite piece of equipment. You'd be surprised at all the misinformation out there....

+1 I love this thing and for the price we got it at was a no brainer. Hopefully someone can put another GB together. I haven't had to change my bulbs yet based on my readings and they have been in 12 months(got my meter last fall). They are aquamax 14k's and they have lost around 25-30% PAR. I should prolly change them soon but the PAR was high enough to begin with that I still get ~ 300 PAR and up in the top half of my tank right now.

 

[ksc]

what kind of misinformation?

Let's see. 250w Radiums should be changed at 6 months.With new bulbs, par was 1350 in the center of the tank, after 10+ months it is 1250 (Bluewave 7 M80 ballasts). These will probably last another 10 months.
T5's are more efficient than mh's
T5 bulbs last 18 months. Mine have lost about 30% in 6 months.
XM 20k bulbs are good bulbs. Mine lost almost 40% of their output in 5 months, 750 to 450 (Advance magnetic M57 ballast)....

 

[Paul_N]

I thought I read that most of the drop in par occurs with the first 3 months and after that initial drop for the next 15 months the drop is very small. Granted I run my MH lights 6 hours a day, I am going to switch out now...20 months later. Growth is still great and no algae.

 

[JNye]

I thought I read that most of the drop in par occurs with the first 3 months and after that initial drop for the next 15 months the drop is very small. Granted I run my MH lights 6 hours a day, I am going to switch out now...20 months later. Growth is still great and no algae.

generally yes, i have found this to be true as well. but bulbs do go bad quicker and i have tested 3 identical bulbs and one was ~ 200 lower PAR out of the box. So you never know unless you test.

 

[Paul_N]

generally yes, i have found this to be true as well. but bulbs do go bad quicker and i have tested 3 identical bulbs and one was ~ 200 lower PAR out of the box. So you never now unless you test.

I agree you are going to have exceptions like that. I definitely want to get a par meter to test and make sure.