When you say "3 filter RO" do you mean two 10" pre filters and a post filter or what?

What is the exact model # of your RO?

Was the RO working OK before the kid adjusted the pressure?

Was the RO working OK before you changed the filters?

Did you just change the 10" filters or did you change the membrane and/or the post filter?

Did you get the correct filters or just filters that looked like what you needed?

Let's undo the first problem and get the pressure in the storage tank right.

In order to set the pressure in the storage tank correctly there must be NO water in it. Shut off the water to the RO. Open the RO faucet and let the RO drain all the water out of the tank.

When the tank is empty set the pressure between 6 and 7 pounds. You can't use a compressor cause the volume is too small. Use a bicycle pump.

Turn on the water to the RO and wait till the tank fills.