ok today i brought home the new tank,guess i didnt wash my sand well enough its kinda murkey. got the heaters in it, got the new filters running and have my oscar in his soon to be "x-crack shack", movin on up! to the east side! i took half his water out and put in the new tank,his filter is still running on his little house. can i put him and my pleco in the new tank with it being murky still, as long as the water is within the correct parameters?

Sorry, little bit confused. You say this is a new aquarium with a new filter, have you put an established filtration system back on the tank? If not, then you are going to have to cycle your aquarium which will take several weeks, I certainly wouldn't recommend adding any more fish than you've got, I normally wouldn't recommend using Oscars to cycle the tank, however if you've got it already, there's not much you can do.

As for the sand, this is quite normal, it doesn't matter how many times you wash it, your water will turn a little murky when you put the sand in the tank, it should clear within a few days however.

Maybe you could clarify your situation for us?

yes new aquarium new filtration, water is treated, ph is 7.6,nitrate is 0, nitrite 0,ammonia 0.aquarium is 75 gallon u.s,half of the water from the old aquarium is in the new set up but i was afraid to unhook the old filtration and put with new tank because my o wouldnt have any oxygen, i also am waiting for the water to get to the correct temp,right now its 72 f.

i dont think your tank is cycled, nitrate 0.
it should be higher if its cycled.

What about the 10 by 3 by 3ft tank, are you still getting it

Playing Devils advocate. Couldnt you put the old filter in the new tank along with the new filter. I dont know what your old filter is rated too but if you keep a close eye on your levels, maybe a few extra water changes wouldn't this be doable?

Yes James is right, if you move your old filter to the new tank, then it will be safe to add the fish. just make sure you check your water to make sure your levels are good. And few extra water changes may be required!

moved the old filter to the new tank and moved the fish also last night, they seem very content,in fact i am sure i saw them smiling this morning!