Nitrate

I have a 65 gallon tank, I've had it running for about a month to make sure there are know leaks. Just tested water and the Nitrates are high looks like 40ppm or a little more. I'm using RO water all plastic plants and did not put any fish in yet. I did NOT Cycle the tank yet with Bacteria. Is it safe to cycle and start adding fish. All other water tests are good ?

I don't understand why your nitrate is so high if you used RO water and have not yet added anything to the tank. Have you checked the nitrate level in the RO just in case?

The only way to be certain it is safe to add fish is to add enough ammonia to get a reading of 3 ppm half an hour later (to allow it to mix in thoroughly) then test again 24 hours later. Zero ammonia and zero nitrite mean it is safe to add fish. Any reading above zero means it is not safe. If ammonia is still 3 ppm and no nitrite, the cycle has not started so you need to complete a fishless cycle before getting fish - or replace the plastic plants with lots of live plants.

It looks like the RO water Unit I used to fill the tank is bad, I have another Ro unit I checked and that water was good. Will do a water change.
Thank you