If your tank is 30gal I strongly advice you wait for a larger tank before getting Oscars. Aim at 100gals minimum so you can properly keep two. Keep in mind that for keeping one single Oscar -with no other fish in the tank- it requires a 55gal tank as minimum. It is amazing how fast they grow up. Mine went form 5 to 9" and 4 to 8" in just three and a half months, and likely will grow more than that, although at slower rate.

I had to keep those two young Tiger Oscars in a 29g bow for a couple of weeks; that particular tank was cycled but couldn't handle their bio-load, even with sparse feeding and filtration at 25+ times tank's volume per hour, so it entered in a mini-cycle, with nitrites raising from 0.25 to 0.50ppm in 24 to 48 hours, so a 50% partial water change was a must, first daily, then every other day, until I moved them into their final home. This is unwanted stress on both the fish and me that I would try to avoid re-experiencing ever.

Pepe
Santo Domingo

pepetj has given you some really good advice there. If you are keeping oscars you will need a large tank. If you want 2 oscars then you really do need a min of 100g and I would say 125g to keep maintaince within a do-a-ble level. with the 30g tank you will be changing water daily to maintain good conditions.if you can get a 150g or more this is even better. a big fish needs a big home.

I never said I planned on having (2) Oscars, the only other fish that will be in the tank is a Chiclid that will grow 6" at the most. You still think (30 U.S. gallons) will be too small of a tank for them both? Again thanks everyone for the feedback.

to comfortably house an oscar for life you will be looking for a MINIMUM tank size of 55 gallons. that's for one oscar alone no tankmates at all. if you plan on having another small cichlid in with him you can start looking in the 75 gallon range.
you will also have to increase the filtration on the tank. hob filters should be rated for 10 times your tank volume per hour. this means if you have a 55 gallon tank them your hob filters should be moving about 550 gallons per hour.

After cleaning the rocks with the vacum, changing 1/3 of the water and conditioning it every 3 or 4 days, my most reccent reading read: Ammonia tested good, (under o ppm) Nitrite tested great at 0 ppm, but my PH tested in between 8.2 & 8.4 Is my tank ready to give it another try?

thats good readings for ammo,mitrite ,and nitrate but your ph is quite hight you want it closer to 7.0 if possible they make buffers you can us to help lower it