2 fish died and 2 oscars are sick

Question
I have a 75 gal freshwater tank & changed the water as usual, the only thing that happened was the filter got shut off for 48 hours by accident...2 parrot fish died and now the 2 oscars look very sick and about to die.  The ph level was high and I used the ph down tablets yesterday but the water is still very cloudy and the oscars do not seem any better. What else can I do to try and save them?

Answer
Janice...

there are a couple of problems that I can see...

1.  You are poorly stocked- 2 oscars in a 75 gallon are pushing it, to add the parrots, is just asking for trouble.
2.  the ph down tablets can cause flucuations in your ph and eventually a crash, which will cause more harm than the high ph to begin with.
3.  with the filter being out for 48 hours, you may be going through a mini cycle. Test your water for ammonia, nitrite and nitrate.  if the ammonia or nitrite are above .25 do a 50% water change.  

thats all I know to do...do daily 50% water changes and see if that helps.