Roy,
Assuming that you are talking about algae on the front glass:
I have actinic upfront and before I got a decent skimmer, deep sand bed
and Ro/DI + DI water I was getting algae blooms. Now I don't, so the
light wasn't obviously the issue.

One thing that might be an issue is how much light from MHs is getting
to the front glass. My DIY reflector doesn't shadow the front glass,
but does shadow the back a bit, so in my case I had a lot of algae on
the front and just a little on the back.
I still have to scrape front a lot to remove coralline algae... sides
are even worse, but the back is almost clean after almost 2 years.
In my old 55gal, which was "cycling" for over a year I had coralline
algae all over the place and in a hurry...

If you are talking about algae in general, all over the tank:
Placement of lights (front vs. back) should make no difference from
physics standpoint, but laws of physics don't always apply to this
hobby ;-)
Regards
Yuriy