I also think it will be hard to notice the loss of colour or par, in a bulb as it ages. The best test, seems to be a new bulb beside one of the older ones.

I run a lower "K" 400, in between my pair of Radiums.

your right on this but the best indicator is coral grow and color if they slow to grow and shift color I tink it will be more than time to change the bulb and then I will know I should have change the bulb two month early or someting like this

but from the difference compare to the m135 intensity I could tell you anyway I will be able to know at least when they will be there cause the differance was realy big

wath confuse me the most is your test compare a pulse start to the agro
to my eye it is a major difference and Sanjay test result are very different either? lightning is a realy comfusing part anyway :D

I suspect that bluwave ballast dont use regular m135 ballast cause the result I get was realy not good with a M135 I have never see those
bluwave so I can't coment on them the one I have try was a Venture m135 pulse start

how much cost that PAR meter do you have? it could be a nice toy to play with

It is a nice toy to play with and we travel.. just buy the ticket and we will come test your tank :wink: seriously though they are close to 200.00 by the time you get it in to canada and pay all the fees, then you also need a multimeter that will measue acuratly in the mV range.. so I think I am close to 350.00 to 400.00 for what I have. (Hmm could have bought my M80 ballasts instead.... :roll: )

I think Adam's ballast was a regulat 400 watt PFO and not a pulse start..

Steve