NUVO 40 - Blocking Off Return Chamber?

Jud · Oct 5, 2020

Hey folks -

I’ve got a Nuvo 40 AIO, which is a great little tank. My one complaint/issue seems to be with nutrient export. Nearly two years in, I’m still running high phosphates/nitrates.

Started with Real Reef Rock, live sand. Running two MP10’s, a Tunze 9004 skimmer, and an Intank media basket with floss, GFO, and carbon (most times).

Only feeding 3/4 cube every other day, as I’ve scaled back feeding. Have a healthy cleanup crew, and I do around 40% water changes every two weeks. So the DT is generally pretty cleaned and vacuumed.

One thing I’ve noticed is that, like many AIO’s, the back chambers are huge detritus sinks. I make it a habit to blow ‘em out with a turkey baster during WC’s, but I can’t help but feel a lot of this is the cause of high nutrients - especially on the skimmer intake side.

With a skimmer and media basket in chambers 1 + 5, I have two smaller chambers and the center return pump chamber open to play with. My initial thought was to put a smaller pump for circulation down into the return compartment, then throw in some more media baskets with filter floss to catch any free floating detritus.

Emailed InTank for their suggestion, and Steve was great enough to send me an interesting suggestion: seal off the bottom return chamber - at least bringing it in line with the other chambers.

Not sure if putting a pump down there would be enough to prevent detritus, or if I should indeed drain the back compartment and silicone a piece of glass in there. Is there a big function for that bottom reservoir that I would miss?

Hesitant to turn a back chamber into a fuge as I’ve read that the benefits of doing so in such a small chamber are minimal, but have been thinking of adding a CPR or Aquamaxx HOB fuge specifically for help with nutrient export.

Regardless, I’m still making it my goal to address all this gunk building up back there. There has to be a better way!

Pics below of chamber diagram with note on section to block off, and also a couple of tank shots because why not. Let me know what you think!

nbooks · Oct 6, 2020

i have the same tank thats been up and running just shy of 3 months. Have 3 fish currently and 8 or so corals. no skimmer.

I had nitrates running in the 25-30 range for quite awhile as i was having trouble finding chaeto. i probably overfeed, flakes in the am and 1/4 cube mysis in the evening. I then added an InTank floss holder (filled with the blue/white stuff they sell) on the left rear overflow, added a fuge basket with a submersible amazon led in the next chamber, and a their media basket on the right with a bag of carbon.

after a month of growing the chaeto my nitrates are down to 12-15 and dropping (nyos test kit) and my water is clear as glass. i did have to add a bag of chemipure elite due to a phos of 0.3 after starting reef roids, now sitting at 0.1 or less after a week.

the fuge led is leading to some film algae that starts blocking the light needing about weekly cleaning...but overall switching to the InTank equipment made a huge change in my tank

TheWB · Oct 7, 2020

I had the same issues with gunk building up in that chamber in my IM Lagoon 50. It has the same configuration. I ordered a pump that draws water from the bottom. If you remove your return pump you can lower the pump into that chamber, run it for a few minutes to get anything back there stirred up and them pump out the filthy water. It’s the easiest way to deal with that problem. I posted a couple of pictures of the built up detritus somewhere in my build thread, it was ugly. I’ve also now filled those areas with bags of Seachem matrix to create a denitrification zone. They fill the space well. Hope this helps.

Jud · Oct 11, 2020

Little update here. I ended up getting a second pump (Sicce Syncra .5) and putting it down into the center return compartment. Managed to fit it in next to my main display return, a Sicce Syncra 2.

I got a small 1/2” street elbow from Lowe’s and threw it on the pump. Connect the pump to Apex, and now just keep it running constantly. At first, it pumped out a TON of gunk into the display, which had me nervous. So today I did around 80-90% water change, siphoned, and scrubbed out the back chambers.

I had been using a DIY rubble basket in compartment four as a safe home for pods, and quick drag plugs when I needed. After vacuuming it all out, it’s super apparent that it was just a detritus mega trap.

I also got a piece of acrylic sheeting from Home Depot and crudely cut it to fit the center chamber in the rear. Cut some slots for the return lines and a couple cables, and drilled some holes for water to pass through. However, this time I put a piece of pinky floss to fit the space.

Actually really pleased with how it turned out, and hoping that the circulating pump in the main compartment combined with reduced ability for detritus to settle in any of those back chambers should help fix my nutrient problems.

Finally started using a little purigen as well, per LFS recommendation. Running along with carbon and GFO in the media caddy for now. We’ll see!

TheWB · Oct 12, 2020

Nice bit of ingenuity there. A pad in that location will likely stop a lot of the detritus that seems to find its way past the other mechanical filtration.
How are you making the ato work in chamber next to the skimmer in your pic? Is the main sensor in the middle chamber and just the float switch is next to the skimmer?

Jud · Oct 12, 2020

Yeah, that’s definitely the project for this week. I’ve just kind of temporarily placed my ATO float switch in that chamber for the time being.

Im thinking that I just need to sand down that acrylic piece a few more millimeters so that it can slide down that center chamber an inch or two. Then I should still be able to fit the float switch above the filter floss.

The acrylic piece still allows for water to flow through, so I’m thinking just wedging it down a little more will allow ATO to function normally?

TheWB said:
Nice bit of ingenuity there. A pad in that location will likely stop a lot of the detritus that seems to find its way past the other mechanical filtration.
How are you making the ato work in chamber next to the skimmer in your pic? Is the main sensor in the middle chamber and just the float switch is next to the skimmer?