COR -20 Minimum Speed Too Fast For A Red Sea Reefer 250

[jamesreich]

I just completed installation and testing of a COR-20 on a Red Sea Reefer 250. I'm using the standard Red Sea 5/8" tubing and barbed fittings attached to a 3/4" union that is connected to the 3/4" slip fitting. Before connecting the COR I verified my Apex 2016 firmware was up to date. The COR firmware is also current. I ran the COR set up task and ran a few tests to verify the setup. It turns out the COR-20 cannot be set low enough to just maintain a full water column in the return line. I reran IQ level calibration and then manually tuned the minimum speed to 1%. Feed code is If FeedA 005 Then 1. Selecting Feed A slows the pump down but there is still water flowing into the tank. The COR code is below. Is there a way to fix this?

Fallback ON
tdata 00:00:00,0,0,100,0,0,0,0,0,0,0,0,0,0
tdata 05:47:00,0,0,100,2,0,0,0,0,0,0,0,0,0
tdata 08:38:00,0,0,100,1,0,0,0,0,0,0,0,0,0
tdata 15:38:00,0,0,100,2,0,0,0,0,0,0,0,0,0
tdata 20:35:00,0,0,100,3,20,0,0,0,0,0,0,0,0
tdata 23:44:00,0,0,100,0,0,0,0,0,0,0,0,0,0
If FeedA 005 Then 1
If DispHi CLOSED Then OFF

[bigjim]

I was wondering (and too lazy to Google) is the Red Sea Reefer 250 250 gallons or 250 liters?

[Simon P]

I was wondering (and too lazy to Google) is the Red Sea Reefer 250 250 gallons or 250 liters?

54gal display (around 200ltrs) and a 11gal sump (around 45ltrs).
OP, it's possible the COR20 may be too powerful for your set-up. There is a minimum pump speed preprogrammed into the controller and that is hard coded.
It's the same with WAV users; the difference between 1% and 10% is minimal because there's a minimum speed that is needed to get the impeller assembly spinning reliably.

[zombie]

I agree with above. COR20 is way overkill for a 54 gallon tank. COR20 is good for 180 gallon tank at 50% from 4ft rise and good for a 180 gallon tank at 80-90% from a basement sump. For a 54 gallon tank ideal turnover from a 4ft rise would be set at like 15% or 25% from a basement sump.

You might be an engineer if...You have no life and can prove it mathematically.

[jamesreich]

I went with the COR-20 because of its stand alone feature so that I can run the pump when the Apex eventually dies. And then there is not being able to run two COR-15s (one for the return and one for the manifold) and a WAV off the EB 832. After adding a 1LINK module to run the second COR-15, you have spent more than buying 2 COR-20s. Red Sea recommends 660GPH for the tank and at over 4.5 feet head height the COR-15 would be running close to max to make the 660. Better to have the 20 loafing than running the 15 at near max.

[zombie]

I went with the COR-20 because of its stand alone feature so that I can run the pump when the Apex eventually dies. And then there is not being able to run two COR-15s (one for the return and one for the manifold) and a WAV off the EB 832. After adding a 1LINK module to run the second COR-15, you have spent more than buying 2 COR-20s. Red Sea recommends 660GPH for the tank and at over 4.5 feet head height the COR-15 would be running close to max to make the 660. Better to have the 20 loafing than running the 15 at near max.

FYI that 660gph reccomendation is not actual flow but pump rating assuming a typical style pump (max head 8-12ft). Ideal effective flow for a 54 gallon tank after head is approximately 150-250 gph. I see why you chose a COR-20 given the price though.

You might be an engineer if...You have no life and can prove it mathematically.

[Simon P]

I went with the COR-20 because of its stand alone feature so that I can run the pump when the Apex eventually dies. And then there is not being able to run two COR-15s (one for the return and one for the manifold) and a WAV off the EB 832. After adding a 1LINK module to run the second COR-15, you have spent more than buying 2 COR-20s. Red Sea recommends 660GPH for the tank and at over 4.5 feet head height the COR-15 would be running close to max to make the 660. Better to have the 20 loafing than running the 15 at near max.

You could add a ball or gate valve to the COR output plumbing to add an adjustble restriction to your return, thus allowing you to "tune" or "set" your return to give you zero flow at 1%. Since the COR-20 is already overly powerfull for your return flow requirements it could easily overcome that restriction once set back to whatever power setting you require for normal operation.
Seems a shame to do it like that (add restriction) but it's the only solution I can see at this point.

[jamesreich]

Given that my plumbing is already fairly restrictive with the 5/8" return line, anyone using the COR-20 with 5/8" or greater return lines and head heights around 4.5 feet will need some sort of restriction for the feed mode or they will be living with drain noise when feeding. A few feed mode choices are:

1. Shut pump down
Pros
zero flow
no drain noise after it empties
Cons
bubbles in DT after restart
Not fully utilizing the COR’s features

2. Add check valve and shut pump down
Pros
zero flow
no drain noise after it empties
No bubbles in DT if check valve keeps return line completely full
Cons
Added cost of check valve
Additional maintenance on check valve
Not fully utilizing the COR’s features

3. 1 % setting
Pros
Limited flow but not zero
No bubbles in DT
Cons
Drain noise while in feed mode

4. Add restriction to achieve zero flow
Pros
Zero flow
No bubbles in DT
No drain noise after it empties
Cons
Added cost of valve to restrict flow

I’ll be clicking buy on a gate valve this morning to fix my problem.

[Sppf121]

I have a Cor20 to use on the Red Sea 250. I bought it because I am setting up a manifold to supply other items, like a reactor, and an possibly an external refugium. I also want to set up a line for some extra flow in my sump for the area when my 2 part is added to my sump. Also I follow Pelphrey on you tube and the COR 20 works great in his Red Sea 250.