Dwarf puffer tank w/ refugium questions

[Luananeko]

My friend has picked up a 5 gallon Fluval Edge Spec aquarium and really wants to turn it into a planted dwarf puffer tank. I've given her some trimmings of my Hygro Difformis (she knows it'll need pruning to keep it in check), Repens x Arcuata Ludwiga, Sunset Hygro, and Frogbit to get her started. She's going medium-light/low-tech for now due to finances, but may eventually use some DIY CO2.

I'm helping her build a custom hang-on-side 1.3 gallon refugium to give snails and shrimp a safe spot to grow and breed as beak trimming food source, and also so she has a little more water volume to help with stability. Yes, it's a probably a little overkill, but I wanted to teach myself a basic how to do it for when I build a larger system for myself in the future. Since the standard cover for the Fluval tank is really not too easily modified, plus she wants to keep it intact for later (just in case), so I'll be building a custom lid too. I've already made a screen top for my 75 gallon tank, so that part will be easy. Here's the rough plan we've got so far:

Just to clarify, the tank length just covers the non-green sections of the tank. The refugium would be an additional 4" on the side of the tank since that's all the space we have to work with

So my questions are thus:
1) Whats a good refugium pump for this little thing? I was looking at these two pumps:
EcoPlus Submersible Pump - 66 gph: Amazon.com: Pet Supplies
Rio Plus 180 Aqua Pump - 120 GPH: Amazon.com: Pet Supplies

The second one seems like overkill, but I have a hard time believing the first one really can pump 66gph using standard airline tubing... Thoughts?

2) Will having this refugium doom any hopes of having her do DIY CO2 later? I'm trying to minimize surface agitation with the refugium design, but I wasn't sure if it was possible since I've never done a project like this before (first time with Co2 or refugiums).

Any input you guys have would be appreciated, thanks!

 

[Terrance]

Snails do produce a lot of waste. Once the population gets going, the water quality will suffer. At that point, your friend will have to start throwing away snails (particularly the larger ones). IMO the added refugium is not worth the time. Pest snails can live through bad water quality and through cycles. A DP are not able to do the same.

I like the Rio. If you build it properly, then the system should be able to work with CO2.

 

[Luananeko]

Our worry is that pest snails won't be able to keep a population going with the voracious little puffers snacking on them constantly in the small space. She doesn't have any source of snails for beak trimming, so she needs to grow them somewhere. Keeping their population in check isn't a worry since I've told her how I keep the crew that hitch hiked into my tank under control (haven't bothered to erradicate them since my dwarf chain loaches love them as snacks).

 

[Terrance]

DPs do not get overgrown teeth, but the snails are very nutritious food source. Many other hobbyist reports no overgrown teeth with soft food diet. I never fed my female dwarf hard food. Even if you feed snails, most DPs figure out to go straight to the meat and avoid the shell.

Not all puffers suffer from overgrown teeth. I have not fed my Turdigus puffer any hard shelled food for over 1 year. No signs of overgrown teeth at all.

 

[Luananeko]

Ah cool, didn't know that! I guess the overgrown teeth stuff we read was blown out of proportion then. She really wants to keep shrimp though, which DPs supposedly will snack on. Should we keep them in the refugium instead of the snails so that if some get eaten there will be some that still make it?

 

[Terrance]

yeah I would really consider adding red cherry shrimps in the refugium instead of snails because the shrimps produce less waste.

 

[Luananeko]

Shrimps it is! No love lost on snails If they happen to hitch hike in so be it, she'll keep their numbers in check, but otherwise she won't freak about not having any in there. Thanks!