Well I've decided I'm going to change out my fluorescent tubes in my bedroom for daylight ones because I prefer the colour. I'll be changing a 4ft 36W tube and a 3ft 30W tube which are both halophosphate white tubes for the equivalent tubes in triphosphor daylight 6500K.

What I want to know is, will they be bright enough to look natural like daylight or will it just look cold and sinister? The 3ft tube is 2350 lumens and the 4ft is 3350 lumens, the room has a white ceiling and light blue walls an is about 12x12ft.

The thing that started this was the 2 vintage 15w tropical daylight tubes I bought, the colour is really cool and white and even my Mum went 'Wow, now that is nice!'.

I think 5600lm (you didn't specify, but i expect one 36W and one 30W tube) of daylight should be enough to wake up...
But i would combine it with some warmer and dimmer alternative (200..500lm of 2500..2700K) to be used when going to bed, otherwise i would have troubles to sleep (nearly a million of years using fire in the safety of a home cave made it's impact on human specie... :-) )

I did have concerns about sleep because I struggle enough as it is. I will be having a 20W 3500K tube and a 25W 2700K CFL in the room too which should be alright.
Thanks for your help

It's really a matter of personal preference, but I didn't really didn't like the color. It made everything look way too cold. I changed it out for 5000K (Philips 850 is what I use)I think it will be accentuated with blue walls you have.

I like 850 for all around general purpose. 2700 and 6500 were the only available screw-in CFLs for a long time, but 5000K is starting to show up in retail stores in the U.S.

I also like 958. It's very close to sunlight in my opinion, but its only about 60% the output of tri-phosphor. 

I prefer the triphosphors 840 color. It is a more neutral white then the triphosphors daylight and together with the warmer triphosphors, have slightly higher lumen output then triphosphors 865.

I prefer the triphosphors 840 color. It is a more neutral white then the triphosphors daylight and together with the warmer triphosphors, have slightly higher lumen output then triphosphors 865.

835 is the most commonly used ones around here for commercial and institutional. 841 comes second. 

Here (Czech rep.) the most common (from newer installations) is /840 (/740 for QMH and /942 for CMH), second most frequent is /830 (mostly fluorescent, sometimes 3000K QMH, the CMH /830 i've seen running only in my own torchiere)

I prefer daylight (6500K) lamps best also, but the warmer colors are better when winding down to go to bed.  I have a 2700K 23 watt CFL in my bedside lamp and a PL13 magnetic CFL in my lamp on the night stand.