Raising alk will lower the CA. You can use baking soda, alk/dkh buffer, whatever you choose, the result will be the same. As for the steps on reducing/slowing the algae, these are the steps that people have listed. There is no other effective way, short of maybe manually ripping the stuff out as needed. The second thing to consider is if the algae is that bad, theres a chance your scrubber may not ever fully mature, as all the algae in the main tank will use up the nutrients well before the unestablished scrubber has a chance.