problem with flatline tank

[DrDemented]

My flatline tank has a real slow leak. I filled it up to 3000psi, turned the valve off and left it alone. a week and a half later it was at 2000psi. I tried to tighten put new teflon tape on the gauges and burst disk and that did not good, any other suggestions?

[BlackVCG]

Fill it up and then put it in a bucket of water. Look to see where the bubbles come from. That's where your leak is. Most likely it's the fill nipple check valve or one of the gauges.