10K MH light goes yellow then back to white?

[skuykend]

I have two hamilton 10K 250's over my 90Gal which have been running about 6 months 5-8 hours a day. This weekend I decided to clean and polish them... I let them cool down then cleaned them with RO water and then polished them with an acrylic polishing cloth. Didn't fire them up till the next day and one shifted spectrums to make it look yellowish, it ran like this for a few hours.

I turned the power off and unscrewed the bulb a little less than a 1/4 turn to rotate the 'guts' to be more parallel to the water and turned it back on and it came up white!

After another power cycle it came up yellow again but now seems to brighten back up to white after 15-20 minutes.

Is this a normal thing or is this not the proper way to clean a bulb?

Thanks,

Steve

[PaulErik]

Everything sounds fine.

It’s usually recommended to clean the outer bulb with a soft cloth and rubbing alcohol. The color shift is normal. If the lamp was repositioned it can take a few hours or days to stabilize.

Hope that helps

[skuykend]

Thanks!