But the Walstad is tried and true, so I will have to trust her. Any ideas for some emergent plants that stay small?
Don't do that! I used that logic recently when I bought her recommended "Miracle Gro Organic Choice Potting Mix". I saw that its main ingredients were composted bark and chicken litter and I thought, "wood and excrement? Well, it's recommended by Walstad, so I'll try it" and now look at my tank! It. Was. Awful. So, lesson learned: think for yourself. The reason why both bioballs and plants wouldn't be a good idea is because both nitrosomonas bacteria and plants eat ammonium. Because they both eat the same food, they compete with one another. And competition being what it is, one might be better at eating ammonium than the other, taking its food away from it. There is a limited amount of food and two mouths to feed.
That is why you shouldn't put bioballs in your refugium,
not just because someone smart said not to.
Further reading:
http://www.fishkeepi...ing-article.htmhttp://theaquariumwi...ical_FiltrationEdit:
By the way, my advice is to go with a chaeto refugium type design with no substrate and Ceratophyllum demersum. I agree that horizontal refugiums need less pump power than ones stored beneath the tank (and you can look at your H. formosa easier), but disagree about the need for emersed plants because I've witnessed the awe and power that is Ceratophyllum's growing speed. I once read that it's native to both North America and Australia and I was like, "Of course it is. The Pacific Ocean is no obstacle to it." XD (joke)
I've never had experience with frogbit but maybe that's something to look into, too.
Edited by EricaWieser, 18 August 2011 - 01:40 PM.