Leaking flow monitor

[Reefs and Geeks]

I just installed my new FMK last night to measure my return pump flowrate, which hopefully after this weekend will also have a UV installed inline. I got it all installed and had leaks at the threaded fitting using the supplied union from Neptune. It's a 1" flowmeter and I've made and retried the connection half a dozen times for about an hour yesterday to try to stop the leaking, but still leaks about a drip a second or so. I started by using a generous amount of pipe dope, then pipe dope with teflon tape (most successful method for me with other plumbing projects), and finally added a pipe clamp to the outside of the fitting to sinch it down. The last method, as odd as it seems, is commonly used on some conical bottom tanks with female threads to help keep the threads from stretching out and breaking. At first it seemed to fix the leak, but I checked it an hour or so later and it was leaking again.

For now, I have a piece of hose under it to redirect the leak back to the sump so I don't have a huge mess on my floor, but I of course want to get it fixed.

I've heard using silicon caulking (GE#1) works well for sealing pipe threads. Has anyone done this? How long would it need to cure before turning the water back on? If it doesn't seal can the fitting be removed and cleaned to try again, or is it ruined? Should I just keep trying pipe dope and teflon tape and hope it just seals at some point? The unions are as tight as I can get by hand, and have used large chanel locks to make them just a bit tighter. I'm afraid to tighten any more with plastic fittings though.

 

[Reefs and Geeks]

Anyone else having flowmeter leaking issues? I'm afraid to try anything else without a bit of direction because i don't want to break the threads or mess them up with silicone if that wouldn't work.

The other side seems to work well, not sure why one side is giving so much trouble.

 

[uninformed]

Sorry to bump a year old thread, but did you ever find an adequate solution? I’m having the same issue.

 

[uninformed]

For anyone else with this problem, I used the RectorSeal No. 5 sealant recommended in the Neptune thread below, using a generous amount on the first 3-5 male and female threads, and it sealed everything perfectly and held under the pressure from dead-headed Varios 6 pumps at 100%.

Sealing Flow Sensor and Other Threaded Plastic Plumbing Fittings

Aquarists tend to use PTFE (Teflon, aka PTE) tape a lot when doing plumbing using threaded fittings such as unions, bulkheads, and other types of plastic fittings. The big reefkeeping forums as well as local club forums are full of advice about how many wraps of tape to use, which type and...

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