[Lord Nibbler]

I have a 37 gallon with 2x65 watts and a 55 with 4x65. The ballasts came with half 10k and half actinic. I need to replace them, what would be a good bulb combination?

I like the actinic on a real long timer for display, but could easily live with 50/50. The aquariums also get some sunlight - they aren't right in front of a window, but are perpendicular along a wall near a picture window that faces south (the 55 getting more light than the 37).

 

[bigstick120]

5000k to 10000K

5000 will be yellow and towards the 10000 more blue/white
You'll find some pinkish in between that are nice and make the reds pop GE 9something75 is a nice one as well as the 8800 or 8000

 

[Lord Nibbler]

Looking at whats available, I'm thinking of going with a dual 6800/10,000 for my daytime light setting and a 10,000/actinic for evenings and mornings (also on during the day).

 

[El Exorcisto]

Using the 50/50 actinic is essentially using 50% of a bulb. Get two freshwater bulbs like GE 9375K or All-Glass 8000Ks and don't look back. If you want to go with what's available to you locally, and those two aren't, get straight 10000Ks. They may be a little crispy for some people, but actinics are a waste of money.

 

[Lord Nibbler]

I installed my new bulbs last night. Half 10k, and half 10k/6.7k.

Its amazing how you forget how bright the lights are when they are brand new! No wonder the plants were looking pathetic.