I have had a lot of IM AIO’s- including yours. Well…not literally yours. IM: 120g, 20g, 10g, and 40g…and the Biocube 29g.
My advice:
AIO’s are best when things are simple. Chemipure, filter socks. Water changes. Maybe add a Wi-Fi dosing pump after a year with some all-in-one. The end.
I’ve tried lots of combinations and spent lots of money and have come to the conclusion that skimmers do nothing on smaller tanks but create headaches, extra stuff to clean, and maintenance every 3-5 days. Nothing like reaching in the back to pull out a little blue rubber grommet that slipped off the magnet of the skimmer when you went to replace the skimmer cup. What’s back there? Eunice worm? Fire worm? Some other horrible evil that lurks in darkness? Yes it will pull out gunk if you get it dialed in. No it won’t really have any meaningful effect. There just isn’t enough room to impact water quality on anything less than a 60g (or so) and then it becomes useless again because the compartments stay the same depth as you go past 50-60g. I’m sure people will “swear” by skimmers on small tanks but the reality is that if they pulled it, they’d have a little more glass to clean for a month or two and then it would be fine.
You’d be better off turning a compartment into a refugium with a magnet light on the back. Which I have done several times. Which has worked brilliantly.
Under stock. A pair of clown and a pistol shrimp/ goby or whatever. This is not a fun place to chase nutrients.
AWC if you have the room. 3, 5 gallon ATO containers on my 40g and an autoaqua AWC was fantastic. Changed a gallon a week and water changes meant once a month or so dumping a container, refilling a container, and away I went.
Flow? Honestly, I would see if I could fit two IM mightyjet 530’s back there and use each return line separately. I’m too lazy to go check if it would work. In my head w/o the strainer it should. Super clean and plenty of flow with spin nozzles or aductors (or whatever they’re called). As I sit here and look at the 20g, an MP10 would be too big in my mind. I used one on my Biocube and an MP40 on my 40g and I recall feeling like the MP10 was bulky in the 29g. I’d go with a small gyre right in the middle on the back wall if it were me. I don’t care for them but space is king in that tank and it’s so small a clean look is important. I can’t recall but I don’t think it fits on the end of the tank.
Flow comes down to what you want to keep so that’s a personal decision. As someone who has fallen down the “I’m going to have a nano-SPS tank! hole, I’m much happier leaving that in my big tank and enjoying the smaller tanks with anemones or zoas and toadstools.
My 20g is currently a FW planted tank. I’m using a Radion XR15 freshwater to light it and it shades on the sides a bit. If I was growing coral, I’d have an XR30 no matter what I was keeping in there.
I am convinced no light in this hobby was designed to run at 90-100% so I always look for the PAR I want at 60-70%. That’s just my 2 cents.
I’m pretty sure it won’t disappoint.
