You should probably have started a new thread instead of reviving an old one but...

The point in a safety cover is to prevent people and animals from drowning if they fall on top of the cover. They're supposed to be strong enough and properly anchored so they can support the weight. Tarp covers like you are using are much more dangerous because if someone falls on top if it, it wraps around them preventing them from swimming up. Here's a recent post about it from PoolDoc: http://www.poolforum.com/pf2/showthr...837#post104837



https://en.wikipedia.org/wiki/Swimming_pool#Covers