Lighting through a glass top?

[fkshiu]

Originally Posted by bv_reefer

do they really cut down on PAR that much? i remember one of the staff members mentioning that it barely lowered PAR by a few percent, and that some 95'ish% of light gets through, good to know though

Here are Sanjay's results for 150W DE HQI bulbs both with and without a 1/8" glass shield:

http://www.reeflightinginfo.arvixe.c...&Submit=Submit

The glass causes a good 20% loss of PPFD (a.k.a. PAR) for nearly all bulbs.