par and wattage

[joeycadre]

so i have this xm 15,000k 250w se bulb over my tank. and now i've been reading and the par is way low, like a 260. whereas a ushio 10,000k is like 630 par. should i swap to get some growth going on? my sps's haven't even started encrusting in the last couple months, let alone grown.

suggestions?

and my ca is up around 440
ph is 8.2
alk is fine
nothing else except like 10ppm nitrates but i just did a water change but haven't checked it again.

[scarson61]

I am going through the same thing with the same exact bulbs. I am glad that you got a par reading from those bulbs because I was at a loss why my SPS were turning green. I am getting some encrusting but it has taken a very long time. I have the bulbs about 12 inches off the water, so I wonder if I start lowering them about an inch every 2 weeks if it would help? The shame of it all is that those bulbs are about 3 months old so it might be a while before I can get some more. On a side note besides the XM 10,000k, what other bulbs have good PAR readings (my ballast is a PFO HQI knockoff).
Thanks Sanford

[joeycadre]

http://archive.reefcentral.com/forums/showthread.php?s=&threadid=624185

cruise through this thread and you can find info on ballast and bulbs.