Here's my Xenia I'm running detectable Po higher NO(algae) high light med flow.
In may at .25 Po these stalks were three times the size under the same light same flow.
If your worried about your algae now is the time to scrape the livin heck out of get it out of the system and let the coral become the competition because the nutrients are so low. IMO. Kill it while it's weak. The higher life forms should be ok and they eat more faster.
Right now your probably stripping the WC of available Po for the corals as well as the algae.