Zero Water Change Planted Discus Tank Proposal???

[Mxx]

From reading through these forums I don't doubt that the premise of my proposed discus tank may leave you speechless, especially as it's heresy for anyone that has committed so much of their lives to the orthodox discus keeping practices. In any case, I'm at the start of planning and researching a tank set-up which I'm afraid intentionally breaks practically every one of the normally accepted rules of discus keeping. And what I'd like to know is if anyone else has done something similar this and under what parameters?

What I'm looking to achieve is a spectacularly beautiful densely planted display tank with many beautiful healthy discus combined with a few other select species, (yeah, sure like seeing the Holy Grail, right?). And I'm looking to achieve this via an inexpensive high-tech low -maintenance over-filtered automated set-up with a fair stocking load yet ZERO water changes apart from topping off the tank occasionally with RO water and NO gravel vacuuming, as I have neither the time nor inclination to do regular water changes. I appreciate this is a contentious proposal to this group, but am hoping this can be considered with an open mind and doesn't rile everybody up unnecessarily.

I'm thinking a 78"Lx24"Dx30"W 185 gallon tank, though possibly even the 108" long 280 gallon tank instead which is hardly more costly for the tank itself. Filtration would be one (or two, as need sees fit) generic Sun Sun canister filters, which filter 530 gph and have a filter volume of 4.4 gallons. I'd have two small corner sumps at either end, one as a screened overflow intake with the other returning water along its height through vertical slots and containing the heater, and possibly a return bar with holes drilled across its length running along the bottom back edge as well to ensure some, though low current throughout the tank and the plant beds and water surface. I'd have a DIY pressurized CO2 system connected to the light timer which is run by a digital Ph controller. Lighting would be via a highly energy efficient DIY LED hood with high powered warm-white (which I think provides the most natural looking light) waterproof LED strips, as many as are needed, which are currently sold quite inexpensively in 5 metre spools.

The substrate would be black flourite (or black flourite sand) mixed 50/50 with small grain inert black gravel. The entire bottom would be densely planted, with the likes of large Swordplants, Giant Vallisneria, and a foreground of Dwarf Hairgrass, (temperature range permitting). I may plant the rear wall as well, in case I don't opt for the 3D background which seems a bit pricey. And I'd have branching vertical tree roots extending down through the entire tank depth if I can find a decent source for such wood. I intend to dose liquid fertilizer as necessary, but I'm hoping I can get away without having to dose root tabs at all once the fish and the tank bed is well established.

As for fish I'd intend to start with 12-18 juvenile captive bred natural colour discus some of which I'd sell off as necessary as they grow, perhaps 10-15 Congo Tetras, a few African Butterflyfish, a group of Rams or Bolivian Rams, several Synodontis Angelicus or as shoal of Panda Corys or Brochis, and numerous Bristlenose and Siamese Algae Eaters. For the discus's initial 9 month grow-out period I'm considering possibly holding off on the Tetras, Rams, and Butterflyfish to be able to concentrate on being able to feed the discus heavily without compromising on water quality. I could feed once or twice a day with frozen food, though I may avoid beefheart if it causes water problems, but I could set up an automatic feeder for additional dry feedings during the day. For temperature I'd target 82 degrees to try to balance the discus's requirements with the upper limit for the other species and the plants.

As a kid I'd kept, bred, and reared mainly South American Cichlids, despite the customary sub-par set-ups of a decade or two ago, and with regular weekly water changes. However, the more I look into it now the more I've been discovering that throwing out all the perfectly good well-conditioned water seems altogether unnecessary. Currently I'm running a small test tank with which I'm trying out some of these ideas and to see if I can maintain stable high water quality with 2-3X overstocked tank, a canister filter for a tank 15x larger, and generous feedings, albeit with dosing with Excel for now. That's still in early stages and I'm still modifying the set-up, but water conditions seem great so far with limited algae (after I added phosphate absorber to the filter).

For the benefit of my fish and to reduce their stress (as well as to minimize the triggers for algae growth, the primary goal with water chemistry would be to achieve balanced stability, (to which water changes would actually be detrimental). With a biological filtration volume of the size I'm proposing, I believe that even with moderate stockings and generous feedings, Ammonia and Nitrites should stay near zero. With dense planting and moderate supplemental CO2, dosing liquid fertilizer occasionally, and medium-high lighting levels, I believe the plants should be able to absorb all the Nitrates (or the ammonia directly which is what plants actually prefer), and possibly all the Phosphates as well. I'd have to carefully monitor Nitrate and Phosphate levels at first, and possibly add a Denitrator filter or Denitrate blocks, and Phosphate Absorber to the canister filter should that prove necessary.

The automated CO2 system would be able to maintain the Ph at a fixed acidity, (although it may prove necessary to add a small bag of gasp! crushed coral to the filter which would dissolve slowly enough to react appropriately with and neutralize the organic acids and carbonic acid produced, thereby preventing the Ph from dropping too far while nevertheless fixing the GH and KH at the desirable soft level for discus.

I would also maintain some fast growing floating plants, which I could easily net out as necessary in order to be able to easily take some nutrients back out of the tank, so while this is still not a closed-system, it should basically equate to food and light in/plants out. And I could control the floating plant quantity in order to shade the other plants and slow down their growth later on so that I don't have to be trimming them constantly.

I wouldn't introduce the discus until the plants were firmly rooted and growing well, at which point I'd dial down the CO2 to a moderate level due to the high water temperatures discus require with its accompanying lower O2 levels. I'm sure some careful monitoring, and fine-tuning of the set-up will be necessary at first, but firm stability should be achievable in time.

Thus, with Ammonia, Nitrites, Nitrates, and Phosphates well under control, and supplemental trace elements and minerals added as necessary, as far as I'm aware at this stage in my research and unless I've thus far missed something, that should perhaps make water changes pointless, shouldn't it? And if that is the case, then shouldn't I be able to keep discus and the other species very happy and healthy in very stable good water conditions, while being able to feed them appropriately to achieve decent growth, with limited maintenance and minor monitoring required once the tank is well established? I’ve seen some mention of potential build-up of vaguely described dissolved organic compounds in addition to nitrates, as well as the suggestion that discus secrete growth inhibiting hormones. I haven’t bottomed out this issue, but surely there must be other ways that this can be taken care of, activated carbon added to the filter weekly? I suppose if it proved absolutely necessary then I could do weekly water changes during the grow-out phase. I could install a separate sump tank underneath, with a plumbed faucet, direct drain, and build a utility sink into the downstairs bathroom as I may do anyway then it might be viable in terms of time if I can simply flick a switch to do so, (but NO gravel vacuuming, especially as the tank bed would be fully covered with plants). What by the way would worst-case scenario be? That I end up with a school of a dozen 2/3 grown discus instead? Not ideal perhaps, but not the end of the world I guess as far as experiments go, and that’d still look spectacular.

I still need to delve into some of the finer points in water chemistry in greater depth and have ordered some books to do so, but I thought I'd put my plan out to the experienced aquarists in this forum as well. I have some time to plan out my tank set-up still, as I'm just now about to embark upon remodeling and extending the living room which will eventually house this display tank, and would appreciate your informed opinions and experience meanwhile. In any case, I'm not looking to breed discus, which I don't really have the time to attend to anyway, I'm just looking to be able to achieve a beautiful natural tank with beautiful fish which I can enjoy without excessive hassle, which to me seems a perfectly reasonable goal to try and attain. Pending success, I may later on also try a similar approach with a small-mid-size marine tank with a trickle filter sump in which I'd be cultivating live rock and Caulerpa algae.

[John_Nicholson]

Why the zero water changes? Nature does not operate in that manner why would you try to keep your tank that way. They call the Amazon a rain forest because....well it rains there all the blasted time. The fish have been engineered for a long, long time to have a "water" change almost daily. You can try to minimize them, but trying to eliminate them entirely is going against mother nature and that normally ends poorly.

-john

[roundfishross]

start with the ecology of the planted aquarium, makes for great reading on this subject

[exv152]

Replacing evaporated water with RO does nothing to reduce nitrates which build up automatically over time, and which have proven to be detrimental to the development and overall health of discus in particular.

[RWD HERO]

There are a few people on another forum (aquariumforum . com) that have densely planted tanks and do NO water changes. Some of these people also have no filtration. Its really amazing what a heavily planted tank can do. With a substrate made of 1' of peat moss and 1" of sand the plants do great and the peat keeps the ph, gh, and kh really stable. The owner of the tank feeds the fish, the fish feed the plants, and the plants take care of the water. Some reading up on tanks like this is really interesting.

[John_Nicholson]

It always seems to be great in the short run. It is the long term that seems to become a problem. I will buy it when someone raises discus in the tank and they live for 15 years.....

-john

[roundfishross]

start with the ecology of the planted aquarium, makes for great reading on this subject

There are a few people on another forum (aquariumforum . com) that have densely planted tanks and do NO water changes. Some of these people also have no filtration. Its really amazing what a heavily planted tank can do. With a substrate made of 1' of peat moss and 1" of sand the plants do great and the peat keeps the ph, gh, and kh really stable. The owner of the tank feeds the fish, the fish feed the plants, and the plants take care of the water. Some reading up on tanks like this is really interesting.

this is the entire theme of the book. it makes for good reading but I do not think it would be optimim for discus

[Eddie]

Its not optimum for discus and if someone wanted to argue it, they would have to prove it. It always comes down to people thinking discus keeping/raising is a new thing, SORRY...the proven methods have long been done and tried decades ago. Good luck with that.

[Mxx]

Thanks for all the comments everyone, and I wanted to touch upon a few of those. Eric, I’m afraid you’d missed the point of my discussion. Many have had success with the keeping of discus in bare-bottom tanks with daily water changes techniques, which volume breeders have pioneered and popularized. However, to control nitrates there are more ways than just that one (as well as potentially easier and less wasteful of ways than throwing out several hundred of gallons of pristine water per week by hand. If you enjoy doing daily WC’s then you’re welcome to it, but personally I’d rather be extracting my own teeth. And doesn’t the constant instability of new water of different chemistry being introduced each day put a stressful toll on fish as well?

If fish are in a bare tank with aerobic bio filters and limited plants then of course there are going to be nitrate problems requiring WC’s. However, the nitrate problems I believe seem to stem primarily from the bare tank rearing technique itself. There are two other ways to control nitrates - proper filtration and/or live plants. The use of an anaerobic filter or anaerobic filter medium of denitrator blocks/pumice/volcanic rock will absorb and eliminate nitrates, as will anaerobic activity in for example a tank’s deep substrate. This, and the anaerobic activity within ‘live rock’ is how marine aquarists keep their nitrates at the undetectable levels necessary for their invertebrates. (If you’re smelling Hydrogen Sulfide then that simply means that the anaerobic bacteria need slightly more water flow).

Healthy live plants will absorb ammonia directly before it is even broken down into nitrites and nitrates, and they also absorb nitrates although they can’t utilize it as effectively as ammonia. Many planted fish tank enthusiasts find that they actually have to dose nitrates to maintain levels at the desired 5-10 ppm. Personally I’m not sure quite how much planting would be required to maintain optimal water quality and nitrates for a well-stocked discus tank, so to try and maintain a healthy margin of error I’d want to look at utilizing both methodologies. And those techniques seem a saner approach for me to enjoy this hobby then constantly juggling instable water conditions in a bare-bottom tank which has no outlet for the perpetually escalating nitrate levels.

In my vastly overstocked small pilot tank I was getting some slight blue-green algae growth, which actually flourishes when nitrates are lacking. (The BGA cleared up as soon as I fixed my broken filter return to reintroduce water current and once I got my DIY CO2 brew going which brought down the alkalinity).

So nitrates aside, which can be quite easy to control, it’s these other dissolved organic solids that I’ve heard vague mention of which I’m more concerned about, that is if they do exist and are detrimental, such as ‘growth-retarding hormones’, of which I have yet to see any conclusive evidence for the existence of. And if they are a problem then perhaps further research would reveal that an ozonizer (with or without a freshwater protein skimmer) or UV sterilizer will oxidize those elements into an inert harmless form or one which plants can utilize. Or perhaps an RO unit filtering the tank can eliminate any remaining problematic organic compounds instead?

As for your concerns John, wouldn’t properly filtering the water with aerobic bacteria, anaerobic bacteria, and plants more closely operates in the manner of mother nature and provides higher water quality than going against nature by artificially doing water changes constantly, especially considering the junk water that comes out of our taps full of hardness, phosphates, metals, and chemicals including chlorine?

I appreciate that apart from my pilot tank this isn’t beyond a theoretical discussion at the moment, albeit a necessary discussion to have before I actually attempt this. And as suggested, perhaps 15 years down the road I will be able to successfully report back that there were other easier alternative to the constant water changes so many of you were doing meanwhile. I must admit that I’m taken aback if no one here has actually tried any such approach as this, as the science of it seems sound as far as I’ve heard thus far. But then again, our flat earth theory took a long time to disprove and remained quite resilient in the eyes of the public for centuries as well. ; )

[John_Nicholson]

"As for your concerns John, wouldn’t properly filtering the water with aerobic bacteria, anaerobic bacteria, and plants more closely operates in the manner of mother nature and provides higher water quality than going against nature by artificially doing water changes constantly, especially considering the junk water that comes out of our taps full of hardness, phosphates, metals, and chemicals including chlorine?"

In the Amazon it rain almost everyday...if anything daily water changes would be....on never mind you are going to do what you are going to do. Logic will not stop you so go ahead and do your"experiment" of course it has been tried about a million times so you might as well get over the thought that you are on to something new....


-john

[Skip]

yikes.. thats like NEVER FLUSHING and trying to filter toilet water and saying.. look.. i can still drink it!!!!! haahaa...

everything looks great on paper, in classroom or in book.. but in field its alot different..
like eddie said.. good luck..take lots of pics and keep us posted..

[intect]

I believe you can be success eventually if you have a big enough tank with a proper number of fishes and enough time and patience. The real question is how you can achieve this balance. There are probably many times of "trial and error" before you get a comparatively stable tank. Also, to make sure the waste produced by fishes can be degraded well you need introduce some nematodes (not parasites). There were some studied showing that these nematodes can help the bacteria to degrade the waste. There was a thread posted by one of our folks who had one this type of tank. His tank is not very big (75-90gal) but he raised 10 discus Juves in that tank although he have to remove all the plants when the discus reached their full size. He only changes the water 25% per week. I am planing to have a tank like that and it seems more reasonable.The other thing is that you need a long time to set up a successful full-planted tank.

[roclement]

This was a great discussion I had at MACNA with the "Filter Guys"...why can't, with all technology available to us, we come up with a filter that negates the need for a water changes?

After 7 hours of talk over many beers the sum up is this:

YOU CAN DO IT, BUT THE VOLUME OF FILTER X THE SIZE OF DISPLAY AND QUANTITY OF STOCK MAKE IT NON-VIABLE FOR AVERAGE HOBBYIST.

Roughly, the size of the filatration would have to be so large that it would be financialy non-feasible, same with filters that remove all the "nasties" from the water, you can do it but the cost outweighs the benefits. Bottom line is with current technology, it is easier/more cost viable to do water changes, now if you want to have a pool size filter, planted or otherwise, to run a 55gal tank so you can avoid water changes, good luck! Keep us posted!

Rodrigo

[Darrell Ward]

People have been trying to "cheat" water changes for as long as I can remember. In the end, the fish always suffer in growth, and overall health.

[Skip]

People have been trying to "cheat" water changes for as long as I can remember. In the end, the fish always suffer in growth, and overall health.

newbies always know better.. (i thought i did too.. but i learned from my mistakes.. even though the SD forum tried their best to warn me )