Switching from MH to T5?

[midgetwaiter]

Originally Posted by kwirky

As for the electronic vs. tar ballast debate, a 250W electronic ballast will draw only 250W while the TAR will draw like 300W. the TAR ballast will output 300W of light however, while the electronic outputs 250W.

You certainly get more PPFD out of an HQI ballast but that doesn't always hold true for standard magnetic, especially with 10k bulbs.

Originally Posted by kwirky

Some people go the whole mile and pair specific bulbs with specific ballasts because you'll get different colour temperatures out of them. Especially for the 400W bulbs.

PPFD varies considerably as well in some cases.