Are you still in warranty? Let the dealership fix it for you.
If not, I'd like to say you have both AN and NPT type fittings. The AN have a flange that mates and seals the fitting, and should NEVER get any kind of pipe dope/sealant. The NPT fittings can and should be sealed, but please do not use tape, pieces of it can break loose and get into your solenoid valve bodies, etc. Use paste.
I believe your solenoids screw into the manifold block with NTP fittings and have O-rings. Meaning you can use paste sealant, then tighten the solenoid in. But the O-rings should be sufficient.
The fittings (nipples) screwed into the manifold block for hose attachment and the ones on the jacks (cylinders) that the hose attaches to, are NTP, with locking nuts. These can be sealed with paste sealant then once snugged in, locked tight with the locking nut.
Fittings on the end of the hoses are AN type. Do not over tighten, they will leak. If you have them appropriately secured and they still leak, it is usually out the back of the crimped-on hose fitting and necessitates (hose) replacement to fix. This should not be the issue based on the year of your motorhome though.
EQ Systems has an issue with the tank vibrating when the pump runs and the tank cracking. Leaks require a new tank. You can help prevent this by looking at the way the pump is mounted and add your own vibration protection for the tank.