I recently bought a new tank 55 gallons, almost a month old now, set it up waited about 4-5 days and added 4 oscars, three of them have died, bought a new one and now the new one and my older one are laying on the bottom of the tank. Bought a test kit to test the water and all readings are normal except for pH which was very high it didn't even read on my chart. Added
tablets that are suppose to lower the ph, get up in the morning and the tank it completley cloudy? What should i do???

What are your watre parameters exactly?

Also your tank is not cycled it can take up to 4 weeks.

You are also Over stocked. 55G Is barley big enough for 1 O by itself.

Please post the actual results of the Ammonia/nitrite/nitrates and pH.
Your filter is most likely not cycled.

Please read the section on cycling a tank.
In the end a 55 will only hold one Oscar with no tankmates.

Really You need to return your Fish to the LFS follow these guides

oscarfishlover.com/tank-setup
oscarfishlover.com/how-to-cycle-a-tank

Then bring home 1 Oscar (If you still want an O) 5 weeks later after your tank is cycled.

btw Welcome to OFL, wish it were under better circumstances!

welcome to the website. Unfortunately you have started off on the wrong track which is why your fish have died. What I try and make people understand is you just cannot fill a tank with water, Chuck a load of fish in after two or three days and expect them to live happily ever after. The aquarium has to be prepared properly so it can support living creatures. I would imagine that your fish have just died from toxic poisoning because there was nothing to remove the ammonia from the water.

You need to read all the information on this website. Unfortunately 55 gallons is big enough for one Oscar only.

We are here to help you but we will only be repeating what is already on the website.

I agree with what has been posted. Your fish have died because of ammonia poisioning. What you need to do is test your water and post the exact results. Rehome all your fish if possible and get a couple of goldfish until your tank has cycled (ammonia and nitrite of zero and nitrate above zero). Then rehome the goldfish and get 1 oscar.