More T5 Florescent Questions

[Rootsnleaves]

Hi,
I am new to the forum but promise I did use search extensively before posting.

I have a 4 bulb T5 fixture, with two 3k and 2 6.5k bulbs. I have had it for 9 months, and have had good results in terms of foliage and root growth. I have also bloomed a phal. dendrobium, which is an accomplishment as my Forum Name indicates.

Based on old posts, I think it is time to replace the bulbs. My question has to do with what combination I should use.

1. Keep the current configuration.

2. Go to 3 3k and 1 6.5k to increase chances of blooming

3. Use 4 5k "Sunlight" bulbs to split the difference.

By the way, those of you who are paying a lot for your T5 bulbs should check out Great Lights 4 Less on Ebay. The high output bulbs are between $22 - $25 FOR FOUR BULBS. Shipping is an extra $16, but that still makes it less than $11 per bulb.

Thanks for your help.