Changed to MH now have brown diatom growth

[sexyfishers]

Ok, I know I have read more often times than not of this happening to others, but didn't realize it would happen once I changed lighting.
My tank is 125g, I had vho pc lighting and was keeping lights on for 9 hours a day. My tank has been running since January. I went through the initial brown algae stages etc and my tank has been beautiful with great parimeters.
The first of October, to be exact 10/2, I put in a whole new lighting setup. It has 2 compacts and 2 halides. I run the halides from 5pm-10pm and the compacts from 8pm-2am. I am now starting to get a brown diatom growth. I have also been adding purple up into the tank. Is it the calcium and minerals that is begining the brown or the lights, or both.
Is this something I just have to wait out, or should I be doing something different? I did cut back on the halides once I noticed the growth as they were on until 1am and the pcs kicked on at 11 till 1 instead of what they are now.
Any help appreciated.
_tonia

 

[jkcrumb]

Do you have any corals in the tank???? Did u start the MH's out for the full 8 hrs right away or did u light acclimate everything???? do you have a cleaning crew???? and what type of sand bed are u using??? deep or shallow??

 

[sexyfishers]

I have 2 anenomes in the tank. One purple carpet and one bubble tip. I haven't added corals yet into this tank. I have a 10 gallon nano with corals in it in which I also upgraded the lights on the same day which is also doing the same thing with the brown stuff. YES, I did gradually do the lights. I had MH for 4 horus, pc for 4. Off for 4 hours, MH for 1 1/2 hrs off for 6 hours pc on for 2 hours then off till the whole cycle came back on again the next afternoon.
As far as cleanup crew there is about 15 different snails in there, not sure exactly which ones are still in. But a variety. Lots of hermits, different varieties. 6 or 7 emerald crabs, 2 serpent stars, anenome crab. humm I think thats it.
It just really surprised me to see the brown algae develop. Guess thats a big duhhh for me. As mentioned, I cut my lights back about 5 days ago, so hopefully that helps.
Any other ideas?
Am I adding too much on the supplements? Would that happen?

 

[sexyfishers]

sand bed.. not sure that has anything to do with it, but it is crushed coral in the big tank, live sand in the 10g. The 10g is pretty deep about 3-4 inches. The crushed coral is about 3 1/2 inches, maybe a little more in some areas of the tank. The brown is just on the live rock, not a huge bloom on everything.

 

[jkcrumb]

I just upgraded my lighting too.........I always had a little buildup of brown algae on my sand bed but never enough to cause concern......
You probably already know this but what is your Specific Gravity level???? My brown really cut down once I bumped my SG upto 1.026..........Also, how is your flow????
I dont think the Purple Stuff would create algae........its mostly for calcium.....by the way, is it working??? (the purple stuff)
I just bought 2 sand sifting cucumbers and the are cleaning out all my algae for me.