LED Lighting Help Please

Hey
Im using some PCB's with LED's attached as lighting.
The boards have 8 channel in parallel. Each channel has 3 LED's in series.
All the channel inputs have been shorted, so that all channels receive the same voltage.
4 of the channels have red LED's in series, which require a voltage of 2.1 V per LED. I have used a 200 OHM resistor to reduce the voltage to 6V.
The other channels have white LEDS, which are at the required 9 V.
The current power supply Im using is a regulated 9V DC with a max current of 2.5A.

I was wondering if I then wire multiple separate boards in parallel how I calculate how large of a power supply I need? Currently I have 7 boards in parallel, which are a bit dull. Ideally I would like to wire up 15. So if anyone could help point me in the right direction that would be appreciated.
Thanks

You add together all the various currents. Since you haven't said what all of them are I can't help you with the calculation.

If you are operating the white LEDs without any series resistance, that's a no-no. All LEDs require some resistance in series to stabilize the LED current value.