are you sure its 140w light you have because thats your problem plus you may have the lights on to long. 8 to 10 hours a day. make sure you still feed the fish because they need other nutrients then just algea.
theres loads of products to give a try for green water (interpet do 1 and plenty...
it does depends on your filter if you want more guppys, over filter your tank and you should be ok. fish tanks very from tank to tank for the time it take to cycle, some take 7 days others 7 weeks you just need to let it do it's thing.
oh yes it would make it quicker if you take some media from...
bear in mind that jewels are not african cichlids and can bully, yes they not as aggresive as others but maybe adding a male into the tank may help her out into the open. give that a try :good:
second on that adam, they do need a min 4ft and bear in mind they need a very good filter. PH needs to be harder then normal tropical fish aswell.
:good: luck
they will take them back, take some water in so they can test it (just so they know your water is fine) and also if you still have the fish them too. :good: luck