Roarke's first iwagumi (20G long)


New Member
Oct 23, 2017
southern california
Hey all! New here, I hope I can bring something to the table.

I'm new so I can't link stuff yet, hopefully the attached image of the tank and stand works.

Lets start with some goals:
  1. Clean tank, meaning as few gizmos visible as possible.
  2. Quiet, this tank will be a foot or two away from our main couch where we spend too much of our time.
  3. As minimal maintenance as possible for a planted tank. I'm a programmer and I hate repeating tasks that can be automated.
  4. And obviously, a gorgeous landscape with a bright green carpet with lots of room for some schooling or shoaling fish to roam.
Planned hardware:
  1. Aquatop cf500uv: Going with a canister filter for the noise issue, and I'm very inexperienced with wet/dry sumps. A canister filter will present some challenges later on though. This is about the biggest canister filter I can fit in the stand. I was looking to get the cheaper sunsun 704 but it looks like its out of stock @ amazon and I'd like a warranty.
  2. Finnex Planted+ 24/7. Not exactly high lighting, but the tank will be less than 12 inches deep with substrate in it.
  3. Custom made dual stage co2 Regulator with a 5 pound tank on a timer.
  4. Ista Inline heater. One of the challenges a canister filter provides is there is no sump to hide equipment. I've never used one of these and I'm unsure of the effectiveness or how they affect flow.
  5. DIY venturi inline/external co2 reactor. I'll have some questions about this below. The design looks simple, enough but I have a feeling having it inline w/ the canister filter will present some challenges.
  6. Custom liquid fertilizer auto-doser: surprisingly simple... 5 or 6 peristaltic pumps that are each controlled via a cronjob running on a raspberry pi. I can dive into this more in later posts once the tank starts coming together.
  7. A whole lot of plumbing in a relatively small space.

With that, there's some loose ends I'm still working out. I'm hoping the filter will be strong enough to handle this "schematic":

intake -> filter -> venturi reactor -> heater -> pumbing to inject ferts from the auto doser -> out to tank

Do you guys think the reactor will slow the flow too much? Alternatively, will there be too much flow going into the reactor for it to be effective?

I've thought of an alternative but more complicated plumbing setup.. let me know if it's a terrible idea.

intake -> filter ---> reactor with it's own external pump -> dosing plumbing -----> out
\--> heater --------------------------------------------------------------------------/​

If that ascii "art" makes zero sense, I'm suggesting putting the heater and the reactor in parallel, and adding an extra pump to help the reactor. There are many modifications to this set up I could make once I start putting pieces of the chain in parallel, I'm nervous I may open a can of worms going down that path.

I'd love to hear everyone's input!

new aquarium stand.jpg
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Reactions: Christophe


Lifetime Member
Oct 3, 2013
Albuquerque, NM, USA
If you go oversize on the canister filter, that gives you enough flow that you can afford to lose some to your reactor and heater. Keep in mind that manufacturers tend to overstate canister throughput a lot. A larger canister will tend to be plumbed for larger pipe/hose. Aim for something that will still give you throughput about 5x tank volume AFTER all the losses. What kills your flow is the combination of:
  1. smaller diameter bottlenecks -- what's diameter of the inline heater? That's where you have limited option to go larger.
  2. over-complicated plumbing -- too many/too tight bends and corners. You can mitigate this effect on your flow by going with larger diameter pipe/hose to reduce friction.
If the flow out of the canister seems high for a reactor, go with a bigger diameter reactor to slow velocity through it.

My first guess is that an added pump in series with the canister will be more complicated than the benefit that you get out of it. Search on 'aquarium pumps in series' -- it'll take you to a bunch of threads on ReefCentral that discuss this.
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Reactions: roarke


New Member
Oct 23, 2017
southern california
Quick update! I have the the tank running and I'm watching for leaks. I did run into a few problems. Here's a picture..

Hopefully that picture isn't huge. I know you guys will probably freak out about that stand being strong enough. Plywood is surprisingly strong. Don't worry though I'll be reinforcing the stand.

I wanted to verify the flow would be good enough on this system before getting to far into the project. This filter is rated at 500+ gph, I'm not seeing near that as expected, but the flow is close to 200 gph so just around that 10x the tank volume guideline.

Here's a video:

I'll describe what's there so far.. I have tubing to the sunsun 304b. The sunsun's outlet connects to an incomplete reactor. I obviously still need to drill a hole into it and plump airline tubing into it. The reactor's output goes into an inline heater. Flow then goes to some pvc where I will be tapping some barbs for the automated dosing lines.

I had a huge headache getting this thing running. The main problem was priming the reactor. The water being pushed out of the filter will water fall down the chamber and create a large air pocket. In order to get rid of this I had to tip the reactor upside down several times to direct the air towards the outlet. I'm worried about the feasibility of this when the tank is in its resting spot and the back of the stand isn't accessible. Any tips for this issue?

I'm thinking of adding a second hole at the top that has a small valve on it that I can open until water squirts out. Seems dangerous though.

My second concern is how to complete the reactor. I plan on tapping the co2 inlet around the middle-bottom quarter of the clear pvc. I've seen people put this inlet at the bottom and at the top of the chamber, unfortunately I'm not in the situation to test both and see what works best.