Spaghetti Algae (Chaetomorpha linum) more commonly known as "Chaeto" does best tightly packed in a refugium or reactor where it helps reduce nitrates and phosphates. It grows quickly and requires strong lighting and a higher flow (moderate to high). It can also be tumbled gently with air stones. 
 
Small - Baseball size
Medium - Softball size
Large - .5 lb (2 Softball size portions)