Thanks for the glowing planthead endorsement WD, but I am sure I don`t deserve it.
I am not trying to be controversial or argumentative, but this problem has been running on two threads so far and the advice has been:
Don`t carry out regular water changes as they will cause an algae bloom. The fish are suffering from ammonia poisoning....bang in large and regular water changes now. Water changes are actually one of the most effective ways of controlling algae, especially in unestablished planted tanks.
Add salt. For crying out loud.
Buy an ammonia test kit.She almost certainly has ammonia present. Look at the fish and green water.
This uncontrolled ammonia level is coming from somewhere, so this thread should be getting to the bottom of that problem, IMO.
You should be carrying out daily, large water changes. The fish are the most important factor here, but it will hit the green water hard as well.
Green water is very difficult to clear. If you can`t clear it through the hard work of water changes, get a UV steriliser.
Most importantly, think of where the ammonia is coming from and act on it. Prevention is easier than cure.
Let`s face it, if we are doing the job right, there is nothing to test.

If things are going wrong, use your noggin to figure out where you have cocked up.