# Keeping Discus in an NPT? Opinions?



## corsair75 (Dec 21, 2011)

I brought home a nice new 55 yesterday to make my first attempt at keeping a non-filtered soil bottom tank. I've kept several low tech planted tanks before, though always with commercial substrates, and usually big filters. In other words, I'm new to dirt but it's not my first rodeo.

I'd really love to try and keep a discus and a pack of cardinal tetras in this tank. I'm not looking to keep more than a single discus, and certainly not interested in breeding it. Just one big pretty fish with some little shiny friends. I was planning on keeping shrimp and snails to clean up after the discus.

So how reasonable is this? Can a simplistic natural tank keep a discus happy? I'd imagine that just like the slightly more techie tanks I'm used to, after 3 to 6 months it shouldn't be hard to keep the water chemistry rock steady. It means warm water, but swords and anubias wouldn't mind it. I'm not sure what species would be happy floating at 82 degrees, any suggestions?

Thanks in advance! Just trying to get some feedback before I go out and start buying stuff. I'm 100% sure that this tank is getting used to try my hand at applying the Walstad method. The discus would just be a really nice bonus. There's a mini-reef parked right across the room, so a good centerpiece will make sure this tank gets its share of attention


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## corsair75 (Dec 21, 2011)

Light came in today. It's a 2 bulb T5 HO from Aquatic Life. I really like their stuff, and this thing looks much better built than the ESU lights I've used in the past. I've got soil and gravel, plants are coming Tuesday so I can start the tank cycling. Have to find some time this weekend (haha!) to paint the back of the tank before I can add water.

Anything I should consider adding to the soil? I've seen both zeolite and CaCO3 in one form or another used. My tap water is liquid rock, so even using half tap/half RO I'm sure my GH and DH numbers will be pretty high. Just call it a day with the soil and gravel?


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## TAB (Feb 7, 2009)

I would not recomend it, while it can be done, its far from ideal. (Mistakes can be very costly.) More so in such a small tank.


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## Michael (Jul 20, 2010)

I'm no discus expert, but it seems that your water chemistry will be the main challenge, not the Walstad method. If your water is already hard, you do not need to add any CaCO3 supplement to the soil.

Zeolite is valued for its ability to absorb ammonia, and might be useful in the filter while the tank is new. But I don't see why you would need to add it to the soil.

I don't want to discourage you from trying this. The prudent course would be to get the tank established and stable with the water chemistry needed for discus before putting one in the tank. You might look for an inexpensive discus, if such a thing exists, LOL.

Good luck, and let us know what happens.


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## corsair75 (Dec 21, 2011)

Michael said:


> The prudent course would be to get the tank established and stable with the water chemistry needed for discus before putting one in the tank.


That's the plan exactly. If I go this route, the discus would be a late addition after things have settled down. It makes a difference now, however, in selecting plants and tank-mates that will be compatible later.

As far as water chemistry, the research I've been doing is suggesting that a discus might be willing to tolerate a little higher pH and hardness if it's not being bred. I'd like to hear that confirmed though. If I can leave a *little* harness to the water, the main challenge for the plants would be the temperature.

I'm not sure why zeolite was being used, I just saw a few references to "kitty litter" being mixed into substrates in small amounts. Sounds like I can keep it nice and simple.


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## TAB (Feb 7, 2009)

most non wild type discus can handle most water chemistrys, what they can't hanlde is dirty water.

Which is where the challenge will be, keeping the water clean enough for the discus, but still dirty enough for the plants.


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## Michael (Jul 20, 2010)

One of the advantages of soil substrates and the Walstad method is that nutrients are held in the substrate, not in the water column. This is also the approach used by ADA. After the initial release of nutrients, mature ADA soils are designed to quickly absorb nutrients from the water column and hold them until they are used by plant roots.

I find it difficult to grow floating plants in my mature Walstad tanks, but species rooted in the substrate do well. I believe this is because there are so few nutrients in the water.

Having no additional biofiltration will make the tank less "forgiving" of mistakes like over-feeding, an unnoticed dead fish, or disturbing the substrate and releasing excess nutrients into the water column during a re-design.

All this is to say that you should be able to keep water conditions good in the tank if you are careful, and stocking rates are low. The easiest "insurance" would be the addition of a generously sized biofilter.

Cat litter is not zeolite. Cat litter is a partially processed clay that has high CEC and acts like other aquarium substrates that do not contain nutrients themselves, but act to absorb and hold nutrients from the water. Cat litter can be used in aquaria, but you must find a plain clay product without clumping agents, perfume, odor absorbers, antimicrobials, etc. This is hard to do!

Several months ago I set up a 90 gallon Walstad tank as a display tank at my lfs. Today I went in and discovered that the owner had stocked it with discus! Maintenance of this tank is not under my control, but I think it will basically be left to its own devices. It does have a big cannister filter with nothing but biomedia in it. So we may have an answer to your initial question sooner than later.


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## corsair75 (Dec 21, 2011)

TAB said:


> most non wild type discus can handle most water chemistrys, what they can't hanlde is dirty water.


I think that this is what is working in my favor. At least if the discus can handle the harder, more alkaline water from my tap, it reduces the complication factor quite a bit. Dirty water hasn't been an issue in most of the planted tanks I've done in the past, at least once they've established. I think as long as I wait for the tank to mature a while before the discus goes in it might work out.

Now as far as filters, I wasn't really planning on using much of anything honestly. The last 'big' tank I did (~100gal) ran a pair of canisters and did very well. The stand for this tank is pretty useless, so a canister would have to sit next to the tank. Not a deal breaker, but not preferred. I've never liked HOB filters, or found them very useful. I don't usually run carbon, so it would be pretty doable to use a HOB Magnum filter and fill up the carbon cage with small biomedia.

If the bio-filtration is not placed in the filter, wouldn't maintaining adequate circulation allow the substrate to populate sufficiently with bacteria to filter the water? The last few tanks I've done skipped bio-media and did very well, though they were quite a bit smaller.


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## Michael (Jul 20, 2010)

It would be an interesting experiment to set the tank up with no filtration at all, but use power heads to circulate the water. I would aim for 8-10 times the tank volume per hour. If you can keep a demanding species like discus in such a set-up, it would be a real validation of the Walstad method.


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## corsair75 (Dec 21, 2011)

Michael said:


> I would aim for 8-10 times the tank volume per hour.


That makes sense, I'm glad you said this. Those are the figures you need in a marine tank to keep everything well turned, I just wasn't sure if the plants would enjoy it. I think lots of water movement would be required so that wastes in the water column can be effectively delivered to the substrate and leaves for processing. A pair of very small (<300gph) prop type powerheads would do it. Lots of water movement, but very little laminar flow that could injure the plants or the discus.

I think a good goal would be a single discus and a small shoal (15-20) cardinal tetras. Skip over catfish and use inverts to keep things clean. Nerite snails are wonderful, wonderful creatures. I'm mildly concerned something like CRS might multiply quickly enough to be a 'pest' with the pile of food a discus is likely to leave behind, but some kind of shrimp seems like a good idea. Active benthic critters will help turn over the upper layers of compost.

Seems worth a shot. Like you said, it would interesting to see if it works. If my kung-fu isn't strong enough I can always add hardware as needed.


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## TAB (Feb 7, 2009)

dicus don't like strong flow. So you need things like spray bars and defusers if your going for that kind of flow.


CRS won't like the temps you need to keep discus at, even if they did they would be food. Discus also don't like to be singles, a pair would be ok, if they are actually paired.


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## Michael (Jul 20, 2010)

"Lots of water movement, but very little laminar flow that could injure the plants or the discus."

Actually, laminar flow is a good thing. A large volume of water moving in a consistent direction and speed is better for uniform nutrient circulation and gas exchange. It is less stressful for fish too, which may important for discus as Tab points out. In laminar flow, a fish can hold its position more easily, or seek a quieter spot to rest.

Part of the reason I suggest such high flow rates is that plants do a great job of slowing water movement. The high flow rate is to compensate for this. Obviously, the density of the planting will affect this--a typical Walstad tank with large plant mass would need more flow than an iwagumi.


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## fishyjoe24 (May 18, 2010)

I would make the 55 a grow out, and get a 75 and make it planted... I've done this before. I had discus before i had plants. the way i got away with it. is i use silica sand. with driftwood, and tied java fern and anubias to the driftwood.... and i grow discus out then put them in the 90 gallon. .


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## corsair75 (Dec 21, 2011)

The tank went live a couple of hours ago. The plants, at least, can get started while the details get sorted out.










It's only a partial planting. I'll add another round once I see how these guys fare in the warm water. The temp is set at 81, which is near everybody's upper limit. 30 gallons was RO/DI, 2 gallons of marine water mixed with reef salt, and the rest was liquid rocks from the tap. Once it all mixes up I'll take some measurements. The specific gravity works out to about 1.001, but I'll double check that too.

Now as far as setting up water movement in the tank. I'm planning the typical dense plantings, so there will be a significant 'safe zone' in the plants no matter how its set up. Would it be easier on the fish if I just plumb up a closed loop type system to simulate a river current? If I do it that way, I could even add a gate valve to fine tune how much water it moves.

Regardless of the fish that end up in here, I'm excited to be trying this method! Can't wait to see how it turns out!


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## Michael (Jul 20, 2010)

Go to this thread http://www.aquaticplantcentral.com/...club/75400-excited-word-about-filtration.html for a really detailed discussion of flow and circulation.

I tried a river tank manifold in one of my heavily planted tanks--it did not work well. (I'm not saying these are always a bad idea, just that they are best suited for fast-stream simulation.) In the absence of a filter, I would suggest two powerheads positioned to create the circular gyre described in the thread above. Since you have a 55 with its long, narrow shape, two 250 gph powerheads will work better than one 500 gph--the flow will be more uniform, and it will be easier on the fish.


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## corsair75 (Dec 21, 2011)

Thanks for linking that thread! I'm about halfway through, and learning quite a bit.

From what I'm reading there, I think there are things I can do to maximize my in-tank biofiltration. I think introducing a burrowing benthic species like MTS will help considerably with increasing the efficiency of substrate. Also, adding some porous rock rubble into parts of the display with good circulation would be a good idea.

I grabbed two powerheads from the pile of stuff I had here. There is one Maxi-jet 1200 with a sponge on the intake, and the outlet pointed at the glass. On the other side of the tank is an Oceanic propeller pump. Between the two it's about 550ish gph. With all the sediment in the water it's easy to see where everything is moving, and I think this will work fine.

The water is testing at 7.8 pH, with hardness and alkalinity off the scale. As was mentioned in that thread, the plants in San Marcos do very well under those conditions. I'm sitting on the same aquifer. If I keep the hard water, it opens an interesting option too. I have an ample supply of live rock rubble in my reef sump. Plenty of the bacteria can likely make the jump to f/w, and it's both attractive looking and porous enough for biofiltration. I could use some space in the sump, so it's kind of win-win.


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