Inconsistent DOS dependability

[Goubli]

I seem to be unable to get my DOS to actually consistently dose the programmed amounts.
I recently had excellent customer service where they replaced my DDR. When I hooked everything back up the DOS has not dosed anywhere close to the amount programmed.
I have calibrated the tubing on both sides. I constantly get air inside the tubing which I have no explanation for due to my correctly attaching the tubing.

I have pt 1 dosing 26mL/day and 2 dosing 25/day and here I am 20 days later with a difference close to 500mL. Again, I have rid the lines of air and recalibrated but still it doesn’t work. What’s the deal here? I am an anesthesiologist so I know my way around tubing, pumps, accurate dosing in small quantities and details. This device seems to need way to much hands on maintenance for me to rely on it for long periods of time (6 weeks) without it skewing off. This is a problem trying to dial it in for the consistency I know I can obtain for my SPS.

What’s the deal here? I ‘m about to say screw it and find another more accurate and reliable system as this has been my first foray with apex equipment.

 

[Kyl]

Air in the lines only has two points of entry: the doser cap or the vessel. The push-fit adaptor on the DDR should prevent any air entry, my suspect with the DOS is always the plastic compression fittings. Are you up to try a DIY fix? John Guest makes a 1/4 push connect x 1/8" FPT fitting that many of us have used for DOS's. It's the same fitting type the DDR uses, and you can use it with or without modding the dosing cap. Only issue is they tend to be sold in packs of 10 only, part number is #PP450821W.

 

[Acrokiller]

I had the same problem when first using mine. My problem was that the tubing didn’t seal well into the nipple. I warmed the tubing and then really jammed it up as far as i could and then screwed it down as tight as I could. The air in the line may be a sign of a leak.

 

[Goubli]

I will attempt the refitting of the current lines, will recalibrate and order the parts. Personally, I prefer the more rigid tubing like RO tubing anyway. Funny, I never had any of these issues with my Spectrapure for my last setup.

Thanks for the replies, but there’s a part of me that feels like this shouldn’t be an issue at the Apex price points. At the end of the day, there’s bigger problems in the world and I don’t want others to think this is a slam Neptune post. Still, if I were someone that really saved up for this product I would be pretty disappointed. This is especially true if I was newer to the hobby and was struggling to figure out why I was having trouble with consistent water quality despite “high end” equipment.

 

[vhuang168]

When you press the tubing into the DDR fitting, you have to make sure that it goes all the way in. If you push the tubing in until it stops, that is not fully seated. You only pushed it up to the Oring. You have to get past the Oring for a full seat. You should feel 2 distinct steps.

 

[TheHarold]

The air in the lines is the answer— a fitting is not completely sealed.

 

[infinite0180]

Do yourself a huge favor. Buy 4 of these. Take a fresh razor and cut the nipples off the dos heads where you normally put the line on but leave the threads. 3 wraps of some teflon tape and screw the fittings on tight. Then use RO line...

https://www.freshwatersystems.com/products/john-guest-female-adapter-nptf-polypro-1-4-x-1-8-nptf

 

[Water Dog]

Here is a Neptune forums link to the John Guest fitting mod. Follow the link in post #3 from the poster Wiretech who originally came up with this fix.

https://forum.neptunesystems.com/showthread.php?13511-RO-tubing-to-DOS-connection

 

[Goubli]

I just wanted to drop back in to let everyone know I completed the modification two days ago. No more air is seen in tubing since the change.

On Soapbox-

My calcium had dropped to around 360. Now I’m wondering how much was actually getting dosed into the tank. I guess I’ll just leave the settings the same and test every couple days to follow. I would be very, VERY curious to hear Neptune’s reasoning behind using the slip on nipple fittings for tubing that are obviously prone to failure WHEN THEY USE JOHN GUEST FITTINGS ON THE DDR!

It seems to me this should have been corrected in future manufacturing of units. (My unit is a couple years old, so perhaps they have changed it—although I doubt it.)

Full disclosure-for anyone that has a DDR I had mine completely fail due to alk creep up the wiring and frying the circuit board. I’m not sure how or why I would have predicted it to fail either. Neptune customer service was responsive and did replace the unit for me. That said, the unit they sent me still has the same build where the circuit board is not sealed to prevent creep from frying it. I had to add silicone to seal it and now I just fill the units to 1500mL to leave a gap.

These are the types of issues that the new hobbyist or those coming back from extended time away (like myself) just cannot plan for adequately. At certain price points I expect a certain level of reliability. Neptune markets themselves as top of the line and price their products as such. No one should have to permanently alter new equipment in order for it to perform as advertised.

Off Soapbox

 

[Kyl]

Neptune doesn't specifically choose to do so, it's an OEM pump cap they're using. Granted they could get something made with the push connect style fitting, but that could limit types of dosing line being used. For instance you can't use the silicone style tubing without some type of insert or adapter, while you can use such with a compression fitting.

 

[Goubli]

I get your point. It makes sense. It does not make sense, however, to use two different types of fittings for the same tubing line.

 

[vhuang168]

The quick disconnect on the DDR is so that you can remove the DDR easily to refill the container.

 

[Water Dog]

The quick disconnect on the DDR is so that you can remove the DDR easily to refill the container.

Do you foresee Neptune offering a V2 optical sensor upgrade kit for the DDR dosing reservoirs which have the older V1 optical sensors?

 

[Goubli]

The quick disconnect on the DDR is so that you can remove the DDR easily to refill the container.

I would disagree with your point to argue the main reasoning they used those connectors is to ensure you create a seal. Otherwise, the fluid cannot be primed into the system.

Personally, I’ve never had to disconnect them to fill the containers, but I do agree it makes them easier to disconnect (if necessary) to refill. I personally don’t want to have to reprime every time I refill.