Freshwater Refugium

I decided that in order to help keep up with my Bass's HUGE bio-load I want to build a freshwater refugium. This will also be a new home for my H. Formosa. I know, for the most part, how to go about doing it, but if anyone has any tips they would be greatly appreciated. The main thing I was looking for was a native plant that doesn't require too high of light and absorbs nutrients very efficiently. P.S. Erica, I AM going to use Kitty Litter!

I decided that in order to help keep up with my Bass's HUGE bio-load I want to build a freshwater refugium. This will also be a new home for my H. Formosa. I know, for the most part, how to go about doing it, but if anyone has any tips they would be greatly appreciated. The main thing I was looking for was a native plant that doesn't require too high of light and absorbs nutrients very efficiently. P.S. Erica, I AM going to use Kitty Litter!

yay! I love kitty litter. It's as nutritious as soil or fluorite, but it sinks (unlike soil) and costs $3 per 25 pounds (unlike fluorite). I recommend a brand that has only baked clay as an ingredient, like Walmart's Special Kitty® cat litter. Avoid brands with clumping chemicals or fragrance.

Certain plant species do better in acidic or basic, soft or hard water, so to better recommend a plant we have to know what your water parameters are. What pH and degrees of hardness (DH) are your water? Also, what light bulbs do you have?

A native plant that doesn't require high light, absorbs nutrients fast... I'd think hornwort (Ceratophyllum demersum) may be the plant you are looking for. Some of the other native plants that I commonly come across (Ludwigia, Potamogeton, Ruppia) need higher light, and IME don't suck up much nutrients in the amount you desire like hornwort would. I found that in higher light (often right at the surface of the water) hornwort tended to burn, but just below the surface in less intense light, it was thick and a very nice green color.

A native plant that doesn't require high light, absorbs nutrients fast... I'd think hornwort (Ceratophyllum demersum) may be the plant you are looking for. Some of the other native plants that I commonly come across (Ludwigia, Potamogeton, Ruppia) need higher light, and IME don't suck up much nutrients in the amount you desire like hornwort would. I found that in higher light (often right at the surface of the water) hornwort tended to burn, but just below the surface in less intense light, it was thick and a very nice green color.

Ceratophyllum demersum is called hornwort because it's hard to the touch. As the plant grows it incorporates lime into its tissue from the minerals floating in the water column. If you have very very soft water with low DH, it's possible that the hornwort may not be able to access enough lime to grow properly. Even so, it's one of my favorite plant species. In my old DH 17 water it would grow like crazy, taking up nitrogen, and the fry loved to hide in it, too. I ::heart:: Ceratophyllum demersum. But I can't guarantee it'll be able to grow well in super soft water.

Also, hornwort has a problem with nutrient exhaustion. You need to go in the tank with scissors about once a week and trim off all the unhealthy stuff and monitor it to make sure it's growing well. It needs a lot of nitrogen. Otherwise it's possible to literally liquify the hornwort. Here's an article where the person is constantly liquifying their hornwort: http://aqualandpetsp...t, Hornwort.htm My hornwort never looked that nasty. It was always much much greener and healthier because I would constantly remove the dead parts and trim the heck out of it. Picture: http://gallery.nanfa... photo.jpg.html

If you use hornwort, you might want to force it to sink by wrapping it around a sunken frame. What I would do is go buy a few feet of half inch diameter potable water PVC pipe and four 27 cent L joint connections. Then I would cut two long lengths of PVC tube and two short lengths. You connect the four sides to make a rectangle and then bury half of that rectangle under your substrate. The hornwort can be wrapped around the exposed half of the rectangle. As long as you frequently rotate it and keep the hornwort exposed to water flow as much as possible, the part of the hornwort that gets wrapped around the pipe doesn't rot too quickly.

Picture of an early attempt, too far off from the substrate, not buried deeply enough: http://gallery.nanfa...ze_001.jpg.html
Photo of successful attempt (you can't see the frame; it looks like the ceratophyllum is rooted): http://gallery.nanfa...l size.jpg.html

Edited by EricaWieser, 16 August 2011 - 10:57 AM.

If you go the Ceratophyllum route, you actually won't need a substrate. Just pile it in there and harvest regularly as Erica suggests.

Floating aquatic plants are also great at removing nutrients from the water. American frogbit (Limnobium spongia) is really good at this - just harvest regularly as with Ceratophyllum. You won't need a deep refugium with this one - 6 inches or so would be fine. I'm particulary fond of this plant.

yay! I love kitty litter. It's as nutritious as soil or fluorite, but it sinks (unlike soil) and costs $3 per 25 pounds (unlike fluorite). I recommend a brand that has only baked clay as an ingredient, like Walmart's Special Kitty® cat litter. Avoid brands with clumping chemicals or fragrance.

Cat litter can be fine. I don't know if I would call it "nutritious", though - it lacks carbon, which I think is a great addition to the substrate. But cat litter is certainly a good alternative to laterite! (Also, as a side note - the clumping litters don't have an added chemical, they are just a different type of clay - bentonite. But still, not good as a substrate because it swells and turns into a jelly-ish mess.)

Erica - soil doesn't really float - what happened to you was that wood particles in the bagged mix you used float. Agreed that it is a royal pain to have that happen. Perlite and vermiculite (also commonly added to commercial mixes) can do that too - especially perlite!

In my extremely soft water hornwort thrives, especially in unheated tanks. I take out large amounts every month because it grows so rapidly even under medium to low light. And it never dies or rots. I don't anchor it at all - it just floats - I like that look. I do not use fertilizer or liquid carbon in any of the tanks I have it in, although I do use liquid carbon in my large planted tank, with excellent results. Obviously, reading this thread, people have had different experiences with it, but this is mine.

I left mine free-floating as well and did wonderfully. I remember getting rid of bucketfuls, and a few here on the forum may still have some. It does melt if there is a significant change in water chemistry. After large water changes, some tips would melt, but this was soon resolved by simply moving the hornwort to the other end of the tank during water changes (so that I wasn't pouring the tap water directly on top of the floating plants).

I left mine free-floating as well and did wonderfully.

Oh yes, most people keep it that way. I just mentioned the PVC frame technique because that's the only way I know of to make hornwort sink without burying (and killing) it, and I like the 'planted' look better for display tanks. But I agree; most people keep hornwort floating, and it grows great.
If you've ever had a chaeto refugium with a big ball of it kind of 'rolling' in the current, that's kind of what a floating ceratophyllum refugium would look like.

And nativeplanter is right; ceratophyllum is a floating plant and doesn't need a substrate to dig roots down into. If you go with a rooted plant species, then I think kitty litter is a good option. And it might benefit the ceratophyllum in a different way; kitty litter might add calcium to the water, which is used in the ceratophyllum's lime. My tap water was 6 DH in Cleveland but with kitty litter substrate was between 16 and 20. The kitty litter dissolved quite a lot into the water. Of course, different regions have different types of clay, and my local kitty litter in Winston-Salem isn't causing an increase in water hardness at all. It depends on where your clay came from.

Edited by EricaWieser, 16 August 2011 - 02:48 PM.

I can't keep frogbit alive, for reasons that I still don't understand . But other floating plants like Riccia fluitans and the various duckweeds have done well for me; just scoop out a bunch when it starts to get thick and toss it in the compost (or give it to your goldfish if you have any). The main trouble I've had with them, especially the very small duckweeds (Wolffia), is that they are like living sand in that they get everywhere and can be hard to get rid of. They can be used in addition to hornwort. Various houseplants that don't mind wet feet, such as pothos, peace lilies, "lucky bamboo", and vining philodendrons also work well.

I can't keep frogbit alive, for reasons that I still don't understand .

Nate - is your water really soft?

WOW! Thanks for all of the info! I can't wait to get this going! Also, what do you guys think about Dwarf Hairgrass?

Edited by Yeahson421, 16 August 2011 - 06:58 PM.

WOW! Thanks for all of the info! I can't wait to get this going! Also, what do you guys think about Dwarf Hairgrass?

I'm quite fond of it but I don't think it will be an effective nutrient remover; it's a rather slow grower. Also, it needs a lot of light.

I'm quite fond of it but I don't think it will be an effective nutrient remover; it's a rather slow grower. Also, it needs a lot of light.

Oh, okay.

I'm quite fond of it but I don't think it will be an effective nutrient remover; it's a rather slow grower. Also, it needs a lot of light.

I agree with that as I had had troubles with it in the past and I was running good light, just wasn't quite enough...

I had never thought about a freshwater refuge.. could be a great place to grow amphipods (if that is the correct invert I am thinking of...)

How do I determine what size pump I want to pump water back up to the main tank?

Edited by Yeahson421, 16 August 2011 - 09:42 PM.

Besides the normal issues (tank size (main and refugium) and how much water circulation you want (GPH)), other issues will be how much water movement your plants and H. formosa can take. I know hornwort will do fine in some current, but I don't know about the H. formosa. If you are really wanting to have a lot of biological filtration, then you would ideally forget about the H. formosa and instead just use plants and 'live' rock or sand. However, if you are just wanted a nice place to have plant and fish life while adding some volume and filtration you your bass tank, then you won't need a high GPH pump. However a limiting factor would be if the pump is rated to lift the water from the refugium to the main tank. Many pond pumps are rated to have 5 feet of vertical pumping power..

Besides the normal issues (tank size (main and refugium) and how much water circulation you want (GPH)), other issues will be how much water movement your plants and H. formosa can take. I know hornwort will do fine in some current, but I don't know about the H. formosa. If you are really wanting to have a lot of biological filtration, then you would ideally forget about the H. formosa and instead just use plants and 'live' rock or sand. However, if you are just wanted a nice place to have plant and fish life while adding some volume and filtration you your bass tank, then you won't need a high GPH pump. However a limiting factor would be if the pump is rated to lift the water from the refugium to the main tank. Many pond pumps are rated to have 5 feet of vertical pumping power..

The main purpose was to have a place to put my H. formosa, so I suppose low gph pump would be good. I will post a MS paint "drwaing" of my idea tomorrow.

Here is a basic drawing:

Here is a basic drawing:

Heterandria are a still/slow water fish, they don't like much of a current. But if the near side of your "grow area" was clear, while the back 3/4 was densely planted, and you positioned your plumbing appropriately, water velocity through the jungle section would be minimal. Amphipods especially like leaf litter and the like, so they'd probably work best in a low velocity area too. Let me restate that, since I catch amphipods in places where there is a decent current, but many amphipods down in the muck at the base of the val-grass ... the leaf litter/muck/mulm that amphipods eat is probably easier to keep in place in a low velocity zone.

(And while Heter have tiny mouths, and probably can't eat adult amphipods, they are industrious little hunter/peckers. So having a self-sustaining amphipod colony in the presence of a bunch of Heters could be a challenge. But that's just a guess, you should try.)

Also, if you have the space, putting the sump on the same level as the main tank would let you use a lower-rated and cheaper pump to move the same amount of water horizontally instead of vertically.

Three quotes from Diana Walstad to consider in planning your refugium (I've added emphasis in places):

#1 - "Just as floating plants are used to remove nutrients efficiently from wastewater, aerial growth can be used in aquariums to efficiently remove excess nutrients from the water. By combining aerial growth with submerged plants, the hobbyist greatly increases total plant growth in the same volume of water. Not only does enhanced plant growth contribute to fish health by removing nutrients and pollutants from the water, but it also discourages algal growth. Aerial growth enhances the health and functioning of aquatic ecosystems." (Ecology of the Planted Aquaruim, p. 154.) She also opines that aerial growth is less important in tanks with (artificial) CO2 fertilization, because then carbon availability isn't so much of a constraining factor.

#2 - "In my planted tanks I have been surprised at how little biological filtration is actually required. When I decreased biological filtration (by removing the filter media in the canister filters), I had fewer problems with nitrate accumulation and water acidification." (Ibid, p. 112.)

#3 - "Although nitrification is essential in tanks without plants, it is much less important in planted tanks. My point is not to advocate dispensing with filters altogether, but I would urge readers to believe in their plants more than trickle filters." (same as #2.)

My summary of that is that emergent plants are best, and your bio-ball filter section could be competing with your filter-by-plant section, to the point of not just being unnecessary, but actually being counter-productive to the functioning of the whole refugium.