Pink Milli Question?

These things aren't mutually exclusive.... changing lighting, without acclimation, does tend to cause bleaching, whether more or less light, unless the bulbs have roughly the same spectral output. Even with the same spectrum and intensity, corals can still bleach. Other factors can also result in bleaching, bleaching is essentially never due to a single factor. Interaction with nutrients, and flow etc... all these things interact. If you have a lot of light, you tend to need a lot of flow, to help the coral remove oxygen byproducts. More nutrients, you get more zoox and again, more byproducts. More alk, and light, you may get more skeletal growth, perhaps too much for the coral to handle etc... And this is under the exact same lighting. So, regardless, you need to light acclimate, unless your tank is 100% the same IMO.

It would be good to know about the specifics of the base to help figure out what else might be going on.

 

Yes it is the skeleton no flesh. I've had the frag for a month now so it's worrying me I don't want to lose it.

Question about the bleaching? If it is bleaching wouldn't it start from the top? I'm asking cause I've never experienced it before.

 

It can. If there is an interaction between light stress and as Dingo said, nutrient stress for example, there could be necrosis. It sounds like that may be the case. In other words, the tissue is dead, not just that is has expelled it's symbiotic algae.

There are various levels of stress response by corals, as described here (in more detail than you probably want to know )
Cellular mechanisms of Cnidarian bleaching: stress causes the collapse of symbiosis

However, from which, this image describes the cellular mechanisms of bleaching by severity:

 

I have found that if a frag has been happy for over 3 weeks and then there is tissue loss, it is usually some sort of swing in parameters or temperature.

 

I just tested my KH an it is between 8-9(143.2-161.1ppm) the only thing I have been doing different is adding without measuring Brightwell's Aquatics Alkalin 8.3 KH buffer cause my ph drops a lot. I realize now that's not a good idea. When I get my parameters stable will the bottom part come back?

 

do you have an ato (automatic top off) to replace rodi water that is lost to evaporation? i found that salinity changes from evaporation is hard on sps corals.
i don't worry about ph, unless i'm dosing alk. theres basically nothing you can do about it anyways. it is about the co2 that builds up in a closed house, room etc....
just make sure your alk, cal, and mag levels are correct and stable.
i used to dose ph buffer and before i knew it my alk was 19 dkh
don't forget to feed the coral (a little goes a long way!!!) i use coral frensy, phytofeast and selcon (selcon is great stuff, corals really respond to it)

 

pH really dosn't matter much compared to alk. Alk changes do matter quite a bit. So, always go by alk, not pH. Changes in alk will definitely stress/kill SPS corals IME.

Now quickly delete this post before Dingo sees it ;D

 

Too late.

 

hehehe...
I dont even need to say it

 

No I don't have an auto top off but I top off daily I keep a close eye on it. It only gets about a gallon a day low so I add it in my self.