All 4 Dos pumps have air and no prime.

[Crashnt24]

Every single day I come home to another dose missed and the line filled with air. What's going on?! I'm so frustrated. I tighten the lines every single day. I'm about to throw these dosing units out the window and boycott Neptune for wasting a lot of money. Here is a picture of my setup... maybe one of you can tell me how to fix their crappy product...

 

[Crashnt24]

Oh and both units are brand new out of the box. No reason to replace 4 heads on the unit's

 

[Water Dog]

Read my post here for the John Guest fitting mod so you can use rigid RO tubing instead of the Neptune tubing and the leaky compression nuts... Read the next few replies as well. I cut the nubs to attach my JG fittings, others did not.

Best Dosing lines for Neptune Dose - Silicone?

So i’ve been using 2 Neptune Dose units to dose triton and also ato water. A couple times i found they were sucking air because the dosing hose that comes with them seems to compress on the connectors to the dose and become loose. That and the lines also became loose on the dosing container. At...

www.reef2reef.com

 

[Crashnt24]

So I got to buy custom fittings, throw out all the silicone colored tubing I bought and chop up the brand new pumps to dose correctly? Ouch. Talk about a waste of a paycheck and a Neptune lost customer.

 

[Water Dog]

It seems if you’re gonna use the stock compression nuts, it’s best to use the stock Neptune tubing. If you’re gonna buy aftermarket stuff, make sure it’s metric 4mm ID x 6mm OD tubing.

 

[Crashnt24]

It seems if you’re gonna use the stock compression nuts, it’s best to use the stock Neptune tubing. If you’re gonna buy aftermarket stuff, make sure it’s metric 4mm ID x 6mm OD tubing.

Well it definitely fits the measurements. Skimz colored silicone tubing is 4mm ID, 6mm OD. I tried buying new Neptune tubing, new Skimz silicone tubing. I think you're right and the problem lies in the head compression connectors. It's just a shame i gotta hunt down those fittings online and replace all the tubing with rigid RO tubing for it to dose properly.

 

[Water Dog]

Yeah, those Neptune compression nuts haven’t had the best reputation since the inception of the DOS unfortunately.

 

[ca1ore]

Bit odd though. I did the John guest mod on both of mine, but previously when I used silicone tubing I didn’t have problems with air. Is the silicone tubing splitting perhaps?