Adjusting par with screens?

[Willbiker]

Hi all

I have built a grow on frag tank which has 3 levels. I tried to achieve 300par on the top, 200 in the middle and 100 on the lower. Ive played around with different t5 heights to find the best middle ground and I get 300par on the top shelf but the middle and lower shelfs are still about 50 par higher than I'd like.

Can you suggest any ways to lower par at the front of the tank and keep it elevated at the back? Maybe a screen? Ive not tried bulb removal yet as I didn't want to affect the colour I have right now.

Thanks

 

[MnFish1]

One problem is that light 'bounces' off the front glass - making it relatively brighter. Setting you lower rack 'lower' would help some.