Ato and macro algea

[WvAquatics]

Ok I love my ato and it works great. My issue is my sea lettuce likes to float against the last baffle and slow flow down. This triggers the ato. I then end up with more rodi water in my sump. Lucky I have 120g so it doesn't fluctuate salinity much. So my question how do I keep the macros down in sump without restricting light and flow?

 

[EW_Fish]

Do you have a picture?

 

[WvAquatics]

Do you have a picture?

Gets caught up on the baffle on the right now I'm 2 gallons higher than what is supposed to be there. It just worries me because I'm planning to add kalkwasser to ato and that would be dangerous if too much rodi water goes in.