Changing lighting...how long should I use window screen?

[jmcmahon66]

I am in the process of changing my lighting from 3x150W 14kk MH and 4x96W PC actinic to 3x250W 10kk MH and 2x150W 20kk MH. This increases my watts from 834 to 1050, but it greatly increases the PAR. I plan on putting window screens to lower the output, but have no clue for how long. Does anyone have a general guideline of how long to keep it on? Thanks for the advice.

Regards,
Dr. Joe

[Detritivore]

put 5-6 layers over the tank. remove 1 layer every week.