Algae is a form of plankton. It contains nothing beneficial to your plants so don't see how that could help. As a matter of fact plankton consume soluble nutrients; the opposite of feeding. Planktonic algea is a sign of healthy pond ecosystem and is beneficial to fish...but not really plants.
Seaweed fertilizer is what I think you want. Kelp meal is basically just chopped up dried seaweed. You can get it in liquid form too. Neptunes harvest is really good stuff btw; your plants will thank you by praying to the cannabis gods.