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Is it normal for a mercury vapour bulb to stay on then slowly turn itself off and then a lil while later turn back on again and keep doing this?? never noticed it before just today, the bulb is about 3 months old, thanks

great question, and one i'd like to get answered too. I've had my MVB for the nature center's DBT for about 6 months now and when it gets turned on in the morning it takes about 15 minutes for it to 'warm up' and turn itself on. I find that pretty odd.

I know they need to cool down before they can be turned on again, though I haven't heard of them needing time to warm up from a cold start. I've only used the self-ballasted T-Rex models.

well mine does turn on straight away, but then after 15 mins it will turn off for 5 and then turn itself back on for another 15 mins n repeat :S

Are you sure you have a porcelain fixture certified for the given wattage to hold your bulb? Many of the MV bulbs (including mine) have automatic switches that turn the lamp off for 15 minutes if it's overheating. It just sounds to me like your bulb is turning on, overheating, turning off, then repeating.

also, is the bulb completely verticle over the basking area?

zoologist wrote:great question, and one i'd like to get answered too. I've had my MVB for the nature center's DBT for about 6 months now and when it gets turned on in the morning it takes about 15 minutes for it to 'warm up' and turn itself on. I find that pretty odd.

the mercury vapor element of your bulb takes a longer time to turn on than an average light bulb. If this time is longer than when it was new then the filament that ignites the mercury vapor part is probably wearing out. I would goto http://www.reptileuv.com and get a mega-ray bulb just in case your current one fails. Mega-rays are great and will last you longer than 6 months.

If the bulb initially didn't do this, I'd say that something is wearing out on it. But three months isn't really long enough to do this. How long is the bulb on each day?

I have to disagree on the general statement on the Megarays. Some last, some don't. You just haven't gotten one that hasn't (yet).

yea my porcelain fixture says 150W n the bulb is 125W