Hello new member here looking through the old forums.
For me there are two main types of algae; algae that grow on the glass/hardscape, and algae that grow on plants. The latter is much harder to remove so I would concentrate your stocking on algae eaters that handle those. Siamese algae eaters do very well at keeping your plants clean from all sorts of algae. One siamese algae eater to your 30g will keep your plants spotless. They even clean algae off hardscape too! Once they grow too big for your tank, you can hand them in to animates. Adult SAE are not vigorous algae munchers like the young ones are (<5months old in my experience)
You could always add a few otocinclus too, but they're no good at eating algae off plants unless you're keeping plants with massive leaves.