This is the colour of our pool at the moment:

It's very pretty but probably not the best for swimming in. It's a saltwater fibreglass pool.
The pool went green last weekend, presumably because the chlorine level had got too low. So I superchlorinated and got the water checked. It got the all clear from the pool shop - heaps of chlorine, stabiliser, ph a little low but fine, salt levels fine. So I bought algaecide, dumped a load of it in the pool on Sunday, and have been regularly cleaning the pool this week with both the vacuum and a brush. After cleaning I've been backwashing the sand filter to dump the dirty water (and hopefully the algae.
But still it's green. Any tips on how to speed up the transformation into crystal clear (blue) water again? The algaecide said it would take up to 7 days to work but I expected it to be starting to clear up by now.
And to help the process, should I have the pool cover on or off? And should I have the solar heating on or off? Any advice appreciated.
Community manager's note: Check out How to maintain a pool for expert advice.