i have never seen powdered phelphlene only ever liquid.
You can also use 'phenol red' available from pool shops and places that sell pool stuff. heaps cheaper and works with the same method.
Hope this helps
Cheers Nick.

__________________
Cheers
Nick.

Roidio 2001 Holden Rodeo 4x4 2.8L TD. 2.5" Straight through exhaust sytem, heat exchanger shower system. 2" Body Lift,
And lots of fruit, B100 for 25,000 no problems.

Elsa 1983 Mercedes-Benz W123 300D. The Fastest Merc in Oz, Loving B100 Burgers