How do you tell old bulbs from new?

I've got some bulbs mixed up two are only burnt in and two have done a crop maybe two?
They all look the same, I've a intensity meter but that is no good a fkd bulb stills burns bright but apparently has diminished PAR.

Star Dog said:

I've got some bulbs mixed up two are only burnt in and two have done a crop maybe two?
They all look the same, I've a intensity meter but that is no good a fkd bulb stills burns bright but apparently has diminished PAR.

Click to expand...

You can get a PAR meter on Amazon for $30

Maggs707 said:

You can get a PAR meter on Amazon for $30

Click to expand...

Really? I thought that it would have been a specialist tool £££, I'll look into them, thanks

Star Dog said:

Really? I thought that it would have been a specialist tool £££, I'll look into them, thanks

Click to expand...

Sorry bro, I was thinking of a LUX meter. Check this video out on youtube though, there's an app that converts your lux readings to PAR.

Well you heard the price of the PAR meter, it's good to have a something that we can work from at least, I've downloaded the app but I've not had a chance to take any measurements, it'll be interesting to see what difference there is.

Star Dog said:

Well you heard the price of the PAR meter, it's good to have a something that we can work from at least, I've downloaded the app but I've not had a chance to take any measurements, it'll be interesting to see what difference there is.

Click to expand...

Keep me posted bro! I downloaded it and haven't used it yet either lol. This whole time I have been using a LUX meter and thinking it was PAR. Oops

HPS bulbs will have black on both sides of the tube inside them, this black grows as the bulb gets more burnt out. An old bulb will have a brown dingy look instead of a clear glass look. Also, some old bulbs have a silver burn on them around the base. Running bulbs hot, like with open hoods and low airflow, will shorten the lifespan of the bulb greatly.

Yup they kinda get burnt