Replacement Apex DOS head on a GHL maxi?

[AZMSGT]

I compared a GHL Maxi replacement head to a picture of a Apex Neptune DOS replacement head. They look identical accept for the color. Also the DOS uses a 4 wheel configuration when GHL only uses a three wheel configuration. Guessing 4 wheel is more precise?

GHL charges $10 more per unit and you can only order a new head from GHL USA or GHL europe so you are stuck with their shipping rate.

The Apex head can be bought all over the place and is typically at the free shipping threshold.

If I have anymore problems with my GHL Maxi head I’ll try the APEX head instead. However if anyone has both I would be interested to know if the APEX head fits the Maxi.

 

[Gungo]

I dont think they'll fit. GHL Maxi head is BIG. The neptune head seems smaller.

 

[AZMSGT]

I dont think they'll fit. GHL Maxi head is BIG. The neptune head seems smaller.

I can’t find dimensions any place. But the DOS head is pretty large too.

Apex

 

[Water Dog]

I run a DOS on my tank and each head on my unit only uses 2 rollers, not 4.

 

[Silver14SS]

I run a DOS on my tank and each head on my unit only uses 2 rollers, not 4.

Have a set of calipers and willing to help OP out?

I compared a GHL Maxi replacement head to a picture of a Apex Neptune DOS replacement head. They look identical accept for the color.

I've been curious as well if they are compatible, sure look close enough in pics, good question!

 

[Gungo]

I run GHL Maxi and I've seen my friend's DOS and GHL maxi is bigger.

 

[Gungo]

Butttt I'll follow this thread in case someone confirms 100%. IF it fits, bingo lol.

 

[Water Dog]

If anything, I would think that if they’re compatible, the Maxi 3 roller head would be an upgrade over the DOS 2 roller head for Neptune DOS users.

Unless someone beats me to it, I’ll take some measurements after work, later this evening.

 

[Silver14SS]

If anything, I would think that if they’re compatible, the Maxi 3 roller head would be an upgrade over the DOS 2 roller head for Neptune DOS users.

It's been a long time since I had a DOS, but maybe there's been a revision? From the pic, are these the 4 rollers OP is referencing? The ones at the 3 and 9 position may be just casting marks...

 

[Water Dog]

Unless they’ve changed something recently, my fairly recent December 2018 built DOS definitely has 2 rollers per head. In fact, I do recall some discussions that I’ve been involved with in the past where we discussed sourcing upgraded 4 roller internal head parts from Avast Marine in order to improve the 2 roller DOS Head.

Replacement Pump Roller

If you need this part for your AVAST Marine peristaltic pump, please email us. We do have them available. We do not have sufficient inventory to sell them for the DOS any longer. Roller assembly for our peristaltic pumps. This 4 roller head is also compatible with Neptune DOS pumps.

www.avastmarine.com

 

[Kyl]

Mine:

 

[AZMSGT]

Mine:

Well, there you have it. The Apex head fits the GHL.

I just ordered those John Guest fittings too.

 

[Kyl]

I'm using them till I find buyers for the last two DOS that don't mind the JG fittings being installed. I never looked at actual roller counts, just that they fit.

 

[AZMSGT]

I run a DOS on my tank and each head on my unit only uses 2 rollers, not 4.

That’s interesting because the picture of the APEX head shows 4 holes filled. I assumed there where 4 rollers. Are 2 of them guide pins?

 

[Water Dog]

Well, there you have it. The Apex head fits the GHL.

I just ordered those John Guest fittings too.

Once you get them in, please let us know how many rollers you have in each head. I’m curious to know if Neptune recently improved their head design from 2 rollers to 4.

 

[Kyl]

I'll check when I get home what the DOS in use are.

 

[Kyl]

GHL 3 roller, 2015/16/17 DOS 2 roller.

 

[Kyl]

I have a new dos cap somewhere that I bought last year when my alk head died, if I can find it I'll note that too.

 

[tastyfish]

I just pulled the head off of one of one of my DOS units to confirm, but by the time I got to the end of the thread to post, you'd got there... lol.

For what it's worth, as a Neptune and GHL owner, the spec & quality is always likely to be better on a GHL model.

 

[WWIII]

I’ve found several different spec models of these dosing heads on aliexpress. They seem to be made by a company called honlite. I’ve thought about ordering some to try, since I now have 3 maxi dosers, but never pulled the trigger. The specs seem at least partly based on the number of rollers? Now with corona virus we all might have a hard time getting replacements for a bit.

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