Solar Cover vs Safety Cover

No, and this substitution is genuinely dangerous rather than just suboptimal. A solar cover has no structural rating and no anchor system, so a person or animal stepping onto one can go straight through into the water with essentially no warning, especially since the cover's surface can look solid enough to stand on until weight is applied. Safety covers exist specifically because tarps and solar covers were involved in drowning incidents historically, which is why the ASTM F1346 standard was developed. If unsupervised access to the pool by children, pets, or others is a realistic possibility, only a certified safety cover (or an equivalent fence barrier) addresses that risk; a solar cover addresses a completely different problem.

This depends entirely on the safety situation, not the heating preference. If the pool is not fully fenced with a self-latching gate and small children, pets, or unsupervised visitors could reach it, the safety cover is the non-negotiable first purchase, full stop, even though it costs several times more. If the pool area is already secured by a code-compliant fence and unsupervised access is not a realistic risk, a solar cover is a reasonable and much cheaper first purchase that improves the swim experience day to day. Cost should never be the deciding factor when the alternative is a real drowning risk.

Many owners do, and they serve non-overlapping purposes across the year. The typical pattern: a solar cover goes on during active swim season for heating and evaporation control, removed while swimming and reapplied afterward. A safety cover goes on during the off-season, or any time the pool will be unsupervised for an extended stretch, providing the structural barrier a solar cover cannot. Running a solar cover as the only barrier through an entire swim season when children have yard access is the scenario safety covers exist to prevent, so pools with that kind of access generally need the safety cover regardless of whether a solar cover is also purchased.

Largely, yes, for the period it's on. A mesh safety cover blocks about 92% of sunlight and a solid safety cover blocks nearly 100%, both of which sharply limit the solar heat gain a bubble cover relies on. This is why the two products aren't really substitutes for each other even outside of the safety question: a pool covered with a safety cover through the swim season won't see the same temperature gains as one using a solar cover, and a pool relying only on a solar cover during an unsupervised period has no structural protection. The two covers are designed for different phases of use, not as competing options for the same phase.