| Pond slime | 10 |
| Pond scum, e.g. | 15 |
| Pond scum and kelp | 18 |
| Pond nuisance | 13 |
| Pond flora | 10 |
| Pond accumulations | 18 |
| Plants containing chlorophyll | 29 |
| Photosynthetic organisms | 24 |
| Organism that can be brown, red or green | 40 |
| Low end of the food chain | 25 |
| Life on the water | 17 |
| Lichens component | 17 |
| Lake or sea life | 16 |
| Kelp beds, essentially | 22 |
| Kelp and nostoc | 15 |
| Kelp and Irish moss | 19 |
| It may fill up your tank | 24 |
| Frog spit | 9 |
| Food for tadpoles | 17 |
| Fishtank problem | 16 |
| Fishtank growth | 15 |
| Fishtank concern | 16 |
| Fish-tank problem | 17 |
| Fish tank problem | 17 |
| Fish tank plant life | 20 |
| Diatoms | 7 |
| Deterrent to swimming | 21 |
| Chief aquatic plant life | 24 |
| Certain thallophytes | 20 |
| Cause of pool problems | 22 |
| Bits of plankton | 16 |
| Birdbath grunge | 15 |
| Birdbath greenery? | 18 |
| Birdbath floaters | 17 |
| Biodiesel source | 16 |
| Big oxygen producer | 19 |
| Aquatic flora | 13 |
| Aquarium owner's bane | 25 |
| Aquarium nuisance | 17 |
| Aquarium microorganisms | 23 |
| Aquarium issue | 14 |
| Aquarium concern | 16 |
| Aquarium build-up | 17 |
| Aquarist's problem | 22 |
| NFL All-Pro Crumpler | 20 |
| Four-time Pro Bowl tight end Crumpler whose first name sounds like a microbiology topic | 87 |
| Football player Crumpler who was on the Falcons, Titans and Patriots | 68 |
| High-school subject | 19 |
| Branch of mathematics | 21 |
| Search for the unknown? | 23 |
| Math branch with many unknowns | 30 |
| Boolean ___ | 11 |
| The search for x? | 17 |
| Subject with many unknowns | 26 |
| Search for x | 12 |
| School subject with variables | 29 |
| Quadratics and such | 19 |
| Math can be "a garble" | 32 |
| It's full of unknowns | 25 |
| It often involves x's | 25 |
| Field with unknowns | 19 |
| Field of unknowns? | 18 |
| Course with x's | 19 |
| Course with unknowns | 20 |
| "X" math? | 19 |
| "x + y = z" math branch | 33 |
| "Solve for x" subject | 31 |
| Rags-to-riches author | 21 |
| Rags-to-riches author Horatio | 29 |
| Author Horatio | 14 |
| Tattered Tom's creator | 26 |
| "Luck and Pluck" author | 33 |
| Writer Horatio | 14 |
| "Ragged Dick" author | 30 |
| Rags-to-riches writer | 21 |
| Ragged Dick's creator | 25 |
| Hiss of history | 15 |
| Hiss | 4 |
| Writer of boys' books | 25 |
| Rags-to-riches Horatio | 22 |
| Ragged Dick creator | 19 |
| Phil the Fiddler's creator | 30 |
| Horatio who wrote the Ragged Dick books | 39 |
| Horatio of fiction | 18 |
| Horatio | 7 |
| Heroic Horatio | 14 |
| Author of boys' books | 25 |
| Alleged Soviet spy Hiss | 23 |
| "Tattered Tom" novelist Horatio | 41 |
| "Tattered Tom" author | 31 |
| "Rags-to-riches" writer | 33 |
| "Rags to riches" author | 33 |
| "Ragged Dick" writer Horatio | 38 |
| "Ragged Dick" author Horatio | 38 |
| "Luck and Pluck" writer | 33 |
| ''Luck and Pluck'' author | 41 |
| Writer who inspired boys | 24 |
| Writer of success stories | 25 |
| Writer of rags-to-riches stories | 32 |
| Writer of boys' tales | 25 |