At a CYA level of 92 ppm, if you don't keep a minimum Free Chlorine (FC) level of at least 6 ppm in a manually dosed pool, then algae can grow faster than chlorine can kill it -- certainly a minimum of 4 ppm is required unless the pool is devoid of algae nutrients or is in complete darkness.
The chlorine/CYA relationhip has been known since at least 1974. There is no such thing as "chlorine lock". There is no magic number where chlorine all of a sudden is locked up. It i ALWAYS locked up to a large extent when there is Cyanuric Acid (CYA) in the water. When the FC is around 10% of the CYA level, over 97% of the chlorine is bound to CYA in a series of compounds (chlorinated cyanurates) that are not effective sanitizers nor oxidizers nor algaecides. Fortunately, it takes a very low level of active chlorine (hypochlorous acid) to kill bacteria and even to kill algae (though it takes far more to kill algae than to kill most bacteria). As the CYA level rises from continued use of stabilized chlorine products, the FC must also be increased or else algae can grow (unless one uses a supplemental algaecide or phosphate remover).
Nascent algae growth will look like an unusual chlorine demand even before the water gets dull or cloudy.
The following are chemical facts independent of concentration of product and of pool size:
For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm.
For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.
For every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by 7 ppm.
Even with a low chlorine usage of only 1 ppm FC per day, after 6 months of Trichlor use, the CYA will have increased by over 100 ppm if there is no dilution of water. Learn more by reading the Pool School