Whatever transition you make in a closed system, you have make small changes so the system can adjust over a drawn out period of time.
I would start running the scrubber, light dimmer at halfway (knob arrow pointing down) and lights on for 9-12 hours/day, reverse of the DT lights. Flow: just enough to cover the screen as evenly as possible (will be somewhere in the 15-25 GPH/in range, for the L4 that's 180-300 GPH).
Then leave it on those settings for at least a month. Cleaning should only be light; swipe your palm across the screen, maybe a light rub with fingertips, then a rinse. You can do this often, like 2-3x per week, as long as you don't get aggressive - and avoid removing any GHA. Diatoms will gather first, that's the slime. You need to rinse that away as diatoms are efficient at nutrient processing and they like the same environment, so they will inhibit algae from getting a foothold. After algae gets a foothold, the slime/diatoms will dissipate.
If you see zero GHA after 2 weeks, but you've got a brown diatom discoloration, back vodka off 25%. FYI from what I've gathered from others, vodka (and to an extent, vinegar) dosing do tend to inhibit algae growth. Not 100% sure why (or rather, I suck at explaining it). So that's the first culprit I usually point to. But cutting it off quickly is asking for trouble.
Generally you need to back off vodka dosing over the course of several months, IMO.
LC - this one you can back off faster, but just monitor levels and adjust as necessary. Algae from the scrubber should start taking care of phos as well, but you've got multiple mechanism in place for multiple things, and they are inter-related in how they work.
Someone can correct me if I'm wrong, but I think oversizing a skimmer by more than about double what it's rated will cause it to run poorly, but I suppose that's not necessarily true for every situation. You have a 90, so if the skimer is rated for 250-300 and you're going to a 150 eventually, eh...might be fine, run it "dry". Regardless, my advice when running a scrubber + skimmer is to run a skimmer that is rated smaller than your tank. Again, a change that you want to make over time - in this case, adjust skimmer back to less aggressive, then when all the other systems have been balanced out (algae scrubber is producing, and you've backed off vodka and LC to much lower levels) then you might swap out the skimmer.
HTH!
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