Historical clue formulations

• Bit of pond scum — 2024-12-17
• Bit of pond scum — 2024-11-25
• Aquarium growth — 2024-10-20
• Pond organism — 2024-07-15
• Plant in a bloom — 2024-06-23
• Plant that contains chlorophyll but lacks a stem and leaves — 2023-08-26
• Simple pond organism — 2023-07-16
• Chlorophyte, e.g. — 2023-05-14
• Bit of film — 2023-03-17
• Growth in an aquatic bloom — 2022-09-20
• Plant used in making biofuel — 2021-01-10
• It helps turn a pond green — 2020-08-23
• Bit of seaweed — 2020-07-06
• Film bit — 2019-09-07
• Bit of pond growth — 2019-03-25
• Bit of pond scum — 2019-02-20
• Simple plant — 2018-09-02
• Lichen component — 2018-08-16
• Word from the Latin for "seaweed" — 2018-08-11
• Bit in a fish tank — 2018-06-20
• Seaweed, e.g. — 2018-05-02
• Pool growth — 2018-04-26
• Birdbath organism — 2017-09-19
• Fountain growth — 2017-05-27
• Pond organism — 2017-05-23
• Bit of birdbath gunk — 2017-01-25
• Bit of pond slime — 2016-04-24
• Bit of fish food — 2015-10-07
• Bit of marine life — 2015-08-09
• Simple aquatic plant — 2014-12-22
• Bit of seaweed — 2014-09-28
• Aquatic organism — 2014-09-14
• Bit of stagnant-water growth — 2014-05-18
• Sea grass, e.g. — 2013-10-20
• Film bit — 2013-10-13
• Morsel for a guppy — 2013-10-12
• Sea lettuce, e.g. — 2012-03-28
• Unwanted swimming pool bit — 2011-12-18
• Mussel morsel — 2011-11-25
• Bit of plankton — 2011-04-18
• Pool organism — 2011-03-06
• Bit of rootless flora — 2010-04-03
• Pond organism — 2009-11-25
• Pond organism — 2009-08-10
• Sea lettuce, e.g. — 2009-07-07
• Aquatic organism — 2009-02-08
• Bit of aquarium growth — 2008-03-26
• Kelp, for one — 2007-10-10
• Pond organism — 2007-10-08
• Bit of plankton — 2007-06-27