# Plant Filter for Discus Breeder Setup



## Lance Krueger (Jan 26, 2007)

Hi there. This is my first time to ask a question on this forum, since I've never had a planted tank, but have been doing some reading to try to familiarize myself with keeping some plants. But I want to do it in a rather unorthadox way, compared to most planted tanks. I breed discus, and am remodeling my 440 square foot fish room, and rearranging all my tanks. I am setting up my bare-bottom breeder tanks (fourteen 29 gallon tanks) on a two shelf pallet rack (which will give me a top row of seven tanks, and a bottom row of seven tanks). Each is drilled for a 1 inch bulkhead, and has an overflow attached to it. I've heard so much positive about using a central, wet/dry system on a bare bottom breeder rack for discus, I was going to hook each breeder tank into a central system for just the breeder rack. But with a wet/dry, you're still left with nitrates, which you would have to keep low with water changes, I know. But I want to have the ultimate water quality for my breeders and my newborn fry to give them the very best chance of success. I was talking to a friend of mine that used to be into discus (now into saltwater), and he told me that I needed to look into refugiums. He told me they are the rage in saltwater tanks, and that a freshwater refugium would allow me to have an even more "natural" filter to give the breeders and the fry even better water quality. 
So after doing a bunch of research on the saltwater forums, and here on Aquatic Plant Central, and Googling on the www, I was wondering if I could run my idea by you and see what pitfalls or problems I might have in this design, as I have little to no personal experience with plants. 
With fourteen 29 gallon tanks, I have about 400 gallons of water in the breeder tanks alone. Then, I'm going to build a sump beneath the bottom shelf of breeder tanks, which will be 96 inches Long x 36 inches Wide x 12 inches High, which will be about 180 gallons. The total system will be right around 600 gallons of water. I was thinking about making part of the sump a refugium, where I thought about having some fast growing stem plants, and/or some floating plants (like water hyacinth or water lettuce). Since this is a discus breeder setup and I'll be keeping the microsiemens at 60-100 with R/O, the Ph will be acidic (probably around 6.0 to 6.5, so the fish will give off ammonium instead of ammonia). So I've read that these plants will suck up the ammonium and the nitrate, which should give excellent water quality. 
In the research I've done, I've found some information on refugiums in freshwater (called plant filters, veggie filters, plant scrubbers, and bog filters mainly in the pond forums), much less with discus, and absolutely no info on refugiums being used on a large breeder discus rack like what I'm planning. I'm trying to figure out some of this stuff in my head before plunging into this and making some expensive mistakes, so here are some questions for you plant gurus:

1. How large should the refugium be? In the saltwater info I've been reading up on, they say 10-20 percent of the display tanks space (which would be 40-80 gallons for my 400 gallons of breeder tanks), but I didn't know if that was right for freshwater. How large should I make the refugium (for the amount of gallons of water in the entire setup), considering I'm making this huge sump homemade, and can make the refugium any size? Should I forget about a separate refugium, and just let the plants cover the entire sump (with about 1500 gallons per hour running past the plants, and through the sump)? The saltwater guys say it has to be separate for the following reason in question #2.

2. The saltwater guys say that the flow through the refugium should be about one turn per hour. In other words, if you have a 40 gallon refugium, the water flowing into it should be choked down to about 40 gallons per hour, with the remaining water going into the sump. I guess this is so the refugium has time to absorb the nutrients. The remaining amount of water from the breeder tanks would go to the sump directly. Any thoughts on if this is too high, or too low of flow? If I did run the full amount of water past the plants, would they uptake the same amount of nutrients, or is slow flow the way to go?

3. I was thinking about using fast growing stem plants (maybe like Milfoil, Hornwort, water sprite, or anachris) in the refugium. Are there any recommendations for which of these stem plants (or any others I didn't mention) that would do good in the acidic, 82 degree discus waters? The plants would just be free floating in the sump, not rooted, since there will be no substrate. Will this cut off light to the plants below if they matte over on the surface? Remember, I don't care about looks because no one will ever see the plants, they're just there to suck up nutrients and improve the water quality, hopefully.

4. I was also thinking about using nothing but floating plants, like water hyacinth or water lettuce, which I understand the roots in the water will act as a mechanical filter, as well as really uptake nutrients. If the entire surface of the refugium is covered, I wouldn't really be able to have stem plants below, since there would be little light penetration into the water column due to the canopy of floating plants. Right? Or can I have both?

6. Would I be better off with floating plants or stem plants, or a combination of both, or something else all together? Advantages and disadvantages to both? Whatever way I go, I want to go as low tech as possible. I will light the plants with a full spectrum bulb (such as a vita-lite maybe?), and provide them with a place (the refugium) so they can uptake the nutrients (ammonium and nitrate) produced by the breeder pairs and fry, but that's about it. They're pretty much on their own. I don't want to dose anything. I would harvest some plants as they fill up the refugium, so they continue to uptake nutrients, but I want it to be just as maintenance free as possible. Or would I need to dose anything?

7. Should I filter the water coming from the breeder tanks mechanically before it goes into the refugium? Or is it best for the poop and mulm to flow into the refugium? I will be doing daily 25% water changes using a bulkhead and ball valve at the bottom of the refugium and sump, so most of the poop and mulm would be drained out each day so it doesn't get too deep, though not all of it. Or I might mechanically remove it with filter floss before it gets to the sump and refugium, if that's the better way to go, though this would be more work.

8. Regarding lighting, should I have this going 24 hours a day, or just for half the day? The saltwater guys want you to have the light over your refugium going half the day during the night hours, when the main display tanks light is off. They say that without a refugium, the PH drops during the night since the corals and live rock are producing CO2 at night. With a refugium run in a reverse lighting cycle to the main tank, the Ph stays consistent, since the refugium consumes the CO2 produced in the main tank during the night.
But with my situation, I'll have no plants in the breeder tanks, so I'm concerned there will be a PH drop during the night, and unstable conditions for the fry. The wet/dry will be running 24 hours a day, but if I only have the plant filter running half the day, will that cause problems for the discus or their fry? Or are there problems for the plants doing this? One concern I have is algae may take over, but in a refugium, supposedly algae is a good thing because it is supposedly very good at eating up the nutrients too. Or should I run the lights only at night, or only during the day? If so, why?
I also thought about having an opaque blind over the water surface of the sump, splitting the sump into two halves. Then lighting each half of the sump on alternating 12 hour light cycles. This way there would always be half the plants consuming CO2 (thus no pH drop) and producing O2. Any thoughts on this?

9. I had originally thought of this as a central wet/dry setup. But now that I'm thinking about doing this natural veggie filter, is there a need for bio balls and a trickle tower? Or can I just use the plants as my 24 hour a day filter? After all, I will have R/O water in this system, so there will only be ammonium produced by the fish, which the plants should consume, right? Without a wet/dry, I would not produce any nitrates, so would no bio filtration and only acidic water and the plant filter be safe enough? The thing I want for this breeder setup is very good quality water, that is very consistent for the babies. Any thoughts?

10. Will my daily water changes of 25% cause problems for the plants, since the water will have so few nutrients in it? Or, maybe the water quality will be so good, I'll only have to change the water every other day, or longer. Any thoughts?

11. One of the advantages of the refugium that the saltwater guys really love is that they have all kinds of invertebrates living in the refugium that would normally get eaten in the display tank. These little critters, like shrimp and worms, are having baby's in the refugium, which flow into the display tank, and feed the corals. I thought this would be cool for my baby discus to have other kinds of live food available to them in the breeder tanks while on the backs of the parents. I would think about it as a 24 hour a day feeding setup. It would be better, I would think, than putting baby brine shrimp in several times per day, though I would if I need to. 
So my question is, what kind of critters would I want to have in my refugium, to keep the plants healthy and to create a food source for my discus fry? I've read about Singapore, Cherry, Ghost, Glass and Amano Shrimp, and even Malaysian Trumpet Snails, freshwater clams and zebra mussels, and even daphnia. Any thoughts on what might be good in my refugium to feed my discus babies? Could I have some fauna in the refugium even if I only have floating plants with no substrate?

I know these questions are long, but I tried to number them to make it easy to separate. Please let me know any thoughts. All info is greatly appreciated.
Lance Krueger


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## furballi (Feb 2, 2007)

The trick is probably to quickly siphon fish poop into the planted tank. Amazon sword grows like mad with a rich substrate. You'll need plently of plant mass to consume the fish waste. I'd start with at least one 50 gal injected with CO2. 

The amazon will also grow emersed (green house effect). There is no need to inject CO2 in air. The dirty water should be filtered thru the substrate before returning to the other fish tanks.


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## ed seeley (Dec 1, 2006)

A mate and I have been discussing improving his plant filter on a centralised system.

First of all, get emerse plants. These will use atmospheric CO2 and so that will not need adding. Either floating plants or simply grow fast growing emerse plants.

Second the faster the growth the more nutrients are removed, basically. So put in very fast growing emerse plants.

The more light, the faster the growth - so put a bright light over your refugium.

I'll try and briefly answer the questions you posed.
1. As big as possible! This will improve the contact time of the water in the 'refugium'.

2. There aren't the same issues here as a saltwater refugium, IMHO. A lot of planted tank use pretty high flow rates. My 180l tank (40 UK gallons) has an Eheim 2128 on it blasting out 750lph. Not high circulation by reef standards, but pretty high!

3. I would recommend, if you're trying these, to try them emerse. Give them an inert substrate, like Hortag (clay granules) in pond baskets maybe, and let them grow out of the water. In my Koi pond, I have Watercress in the stream and it is brilliant at removing nutirents, try that! Just get some from the supermarket and shove it in!

4. This was an option we discussed too. I suggested that you could have the floating plants on the top growing very rapidly and low light plnts underneath like Java moss and Java fern. Even plants like Hygorphila polysperma may grow well under floating plants. Double the nutrient removal and floating plants are far, far easier to crop and remove when they spread. Amazon frogbit, or, if you can bear it, duckweed may be the best choice. Just thing no trimming, just a few sweeps of the net!

5. There is no 5!

6. I would suggest that as your goal is to remove the Nitrate and Phosphate that you don't dose them, but I would think about adding a balanced trace fertiliser to make sure that they aren't limiting your plants' growth.

7. I don't think it will matter, whatever is easiest for you.

8. I would only light for 12 hours, personally. As you've got a trickle filter this will gas out any CO2 produced by your plants/fish (and if you grow mainly emersed/floating plants this won't be an issue anyway!) very quickly and I think your pH will be pretty stable.

9. Keep it running. It's your back up if anything goes wrong. IF the plants don't take up all the nutrients your filter will deal with it - if the plants do take up all the nutrients your bacteria will cope!

10. Keep up the water changes, just add some plant fertiliser in the new water! You may find, when it gets going that you don't need as many water changes anyway! Hopefully!

11. You may find that if you stick with the high flow rates any critters get sucked out too quickly! If you find algae building up stick a load of Amano shrimps in. The adults will cope with high flow and they produce placktonic larvae that need salt water to hatch (so wouldn't suirvive anyway) that would be ciurculated around your other tanks. You may get away with adding Daphnia, Cyclops and other too. A breeding population may stay amongst the plants and survive, or they won't - worth a try when it's all established.

Hope that helps!


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