How to convert Redsea C250 AIO to external sump?

[Bluenote]

I have an 65 gallon RSM C250 from 2015 and adding an external sump with filter sock, skimmer, and refugium. I will be following the E260 design to drill three pipes for a Herbie style overflow.

I need help figuring out what to do with the existing return pumps in the AIO section. Here are some options:

1. Remove both existing AIO return pumps and connect both DT return outlets to the return pump from the sump. I think this may create stagnant water areas that may collect detritus where the old return pumps were.
2. Do nothing. Continue to keep the sponge and filter floss above each of the two AIO return pumps. This does not seem ideal as the overflow rate from the DT is being influenced by these pumps. Also prefer to just maintain filter sock rather than 3 filter media areas. This scenario just seems difficult to control.
3. Keep AIO return pumps but remove filter media. This seems like it may return detritus and waste into the display tank.
4. Plumb one DT outlet to come from the sump return pump and keep the other outlet coming from the AIO return pump. I could use a smaller pump for the AIO return pump to further decrease influence on DT overflow rate.

I'm leaning towards option 4 but option 1 is attractive since it is most similar to a non-AIO setup that I am most comfortable with. I cannot find any info but I think Redsea may recommend option 3.

 

[sullivansp]

Option 4 does seem like a happy medium considering your concerns, but I would personally utilize option 2 based on my experience with a similar situation. Hopefully, the following explanation can assist in your decision-making process.

First, let me preface by saying I converted a Max E-170 rear sump to the under cabinet sump and found what is basically your Option 2 to be most effective. Even though you have the C250 I think this will still apply. Your biggest concerns seem to be the following and I will try to address each one:

1. Flow rate through the DT
2. Detritus buildup in the rear sump section
3. Maintenance load with multiple filter media areas

One way to alleviate the concern of increased flow in Option 2 is something you already addressed- decrease the size (or flow rate if adjustable) of the pumps currently in those sections. You are correct in assuming detritus buildup will occur under Option 1, as well as Option 3. I tried to remove the pump altogether when I upgraded sumps and just utilized the filter media in the rear section and the detritus buildup was definitely a problem. I then tried to use the pump without filter media method (as your Option 3 describes) and though I didn't see a noticeable increase in DT detritus I did have detritus buildup on and around the pumps that increased the amount of maintenance I needed to conduct (at least monthly).

As for maintenance load, yes that was the biggest problem with my setup. I hated having to change filter media in the media rack, the black Red Sea bubble trap sponge, and the filter socks in the in-cabinet sump. But I considered this part of the territory with converting an AIO so resigned myself to the extra maintenance. Ultimately, Option 2 for me was the most useful in maintaining long-term water quality. Hope this helps!

 

[1ByLand2BySea]

I think option 2 will give you least amount of concerns and issues in the long run as mentioned above.

 

[Bluenote]

Option 4 does seem like a happy medium considering your concerns, but I would personally utilize option 2 based on my experience with a similar situation. Hopefully, the following explanation can assist in your decision-making process.

First, let me preface by saying I converted a Max E-170 rear sump to the under cabinet sump and found what is basically your Option 2 to be most effective. Even though you have the C250 I think this will still apply. Your biggest concerns seem to be the following and I will try to address each one:

1. Flow rate through the DT
2. Detritus buildup in the rear sump section
3. Maintenance load with multiple filter media areas

One way to alleviate the concern of increased flow in Option 2 is something you already addressed- decrease the size (or flow rate if adjustable) of the pumps currently in those sections. You are correct in assuming detritus buildup will occur under Option 1, as well as Option 3. I tried to remove the pump altogether when I upgraded sumps and just utilized the filter media in the rear section and the detritus buildup was definitely a problem. I then tried to use the pump without filter media method (as your Option 3 describes) and though I didn't see a noticeable increase in DT detritus I did have detritus buildup on and around the pumps that increased the amount of maintenance I needed to conduct (at least monthly).

As for maintenance load, yes that was the biggest problem with my setup. I hated having to change filter media in the media rack, the black Red Sea bubble trap sponge, and the filter socks in the in-cabinet sump. But I considered this part of the territory with converting an AIO so resigned myself to the extra maintenance. Ultimately, Option 2 for me was the most useful in maintaining long-term water quality. Hope this helps!

Thanks so much for your help. I'm having trouble figuring out how big the AIO return pumps should be. It currently has one 356 gph and one 568 gph that I believe it came with. The sump return pump I am using has a rating up to 845gph though I will probably use 50% of power. Flow recommendations are 5-10 times per hour so 500 gph would cover the redsea 250 at 65 gallon. Could I use ~200 gph AIO return pumps and replace the others? I also have wavemakers in the display tank.

 

[sullivansp]

Thanks so much for your help. I'm having trouble figuring out how big the AIO return pumps should be. It currently has one 356 gph and one 568 gph that I believe it came with. The sump return pump I am using has a rating up to 845gph though I will probably use 50% of power. Flow recommendations are 5-10 times per hour so 500 gph would cover the redsea 250 at 65 gallon. Could I use ~200 gph AIO return pumps and replace the others? I also have wavemakers in the display tank.

I think there would be no issue in replacing your current AIO return pumps with ~200 gph ones. With the smaller pumps in the rear compartment, the water turnover would be lower but still enough to prevent any stagnation and detritus buildup. As you mentioned, your in-cabinet sump return pump alone would satisfy the typical 5-10x total turnover many people recommend. Couple that with your intention of using wavemakers you should have plenty of water movement.

In my Max E-170, I used a VarioS-2 (a 792 gph pump but I set it at 60% power) as the in-cabinet sump return pump, the stock Red Sea rear compartment return pump (not sure what setting I used to run it at but it was adjustable), and 2 Vortech MP10's in the display (both usually running Reef Crest mode at 50% and 75%) and I had more than enough flow for my purposes. Ultimately, it is your personal preference in determining how much turnover is best for your individual tank. Hope this helps!