Excess nitrates problem, FW   11/1/07
Dear WWM,
<Melissa,>
I have/had a 5 gallon tank with two panda Corys, mechanical and biological filtration.
<Hmm... 5 gallons too small for such fish, and really too small for any fish. The main problem is a lack of stability, so even if a 5 gallon tank is fine one day, by the next it can be a death zone. The bigger the tank, the slower such changes, and the more time you have to fix them. Experienced fishkeepers can usually run a 10 gallon tank safely enough, but for beginners there is no doubt in my mind a 20 gallon is the bare minimum for anything like a consistent chance of success.>
Yesterday when I left my house, my fish were fine. One of my Corys was displaying some clouded eye a few days ago, but it seemed to be improving.
The other Cory was unaffected.
<Cloudy eyes don't tend to go away, and even if they do, they're really an indication of infectious agents in the water. In other words, this should be an alarm bell.>
When I got home about seven hours later, there were these tiny worms in my tank. They are very small, ranging from about 2 to 10 mm long, almost translucent, and free-swimming. They resemble Planaria but are not white. I suspect them to be nematodes.
<Quite possible. Nematodes such as these are harmless, and simply turn excess food you are giving your fish into more nematodes. Cut back the food, clean the tank more rigourously, and the nematode population will die back. Again, an alarm bell.>
I have not added anything new to my tank recently. My java fern has also started yellowing suddenly for some reason, I don't know if this has anything to do with it.
<Likely not; are you fertilising the water? Like any plant, Java fern relies on minerals such as iron and magnesium from the water. This is used up over time, so at least monthly you need to top up with plant fertiliser.>
Plus, there are tiny white specks crawling on the inside of my tank walls.
<Could be nematodes, planarians or even some sort of tiny crustacean such as ostracods.>
I also lost both Corys over the last 12 hours.
<Sorry.>
I suspect both the worms and the fish loss to be due to excess buildup of nitrates in my water.
<Wrong. The nematodes and the nitrate levels (which you don't quite) are a product of poor aquarium care. Provided you don't give fish too much food, there should be no food for nematodes to turn into even more nematodes. Likewise, nitrate comes from food, not thin air. So if you have relatively high levels of nitrate compared with the water you put into the tank, this means you are adding too much food and/or not doing enough water changes. Bottom line, the nitrates and the nematodes were warnings about a systemic problem with the tank; without fixing that problem, you allowed the situation to become critical, resulting in dead fish.>
However, I don't see how this could happen as I siphon thoroughly once a week along with 20-25% water changes.
<Not enough. The smaller the tank, the more the water changes need to be. Minimum, 50% a week for this system.>
I also underfeed.
<Apparently not, or there wouldn't be any worms. Understand this: nematodes are animals. They eat stuff. They eat fish food. They can't survive on just water and gravel. So if the nematodes are multiplying, that can only mean there is "stuff" in there for them to eat and turn into baby nematodes.>
Although I did a full siphon and water change two days ago, yesterday I was still able to siphon out a very large amount of dirt from my gravel. This included white and brown specks about 1 mm as well as microscopic specks that looked more like dust than anything.
<Organic detritus. This is the stuff you need to remove with each water changes. In a bigger tank, this really isn't a problem, but in a small tank, organic decay can be critical, resulting in things like rapid pH drops.>
Today, I siphoned again, and even though I siphoned yesterday and did a 40% water change, today after an hour of siphoning I was still able to stir up a significant amount of this dirt.
<Bizarre. Let's review how the gravel should work. In a tank with an undergravel filter, you need around 5-8 cm of gravel, through which water is drawn. Each week you need to stir the gravel and siphon up the solid waste that accumulates there. In tanks without undergravel filters, you don't need a deep bed of gravel unless you have rooted plants. In your case, if the only plants you have are Java fern (which you NEVER stick in the gravel but attach to wood/rock) the gravel need only be 0.5-1 cm think. Enough to cover the glass but no more. This should be very easy to keep clean. In tanks with plants that have roots (Vallisneria, Amazon swords, etc.) the substrate needs to be much deeper, around 10 cm. Actively growing plants will largely keep the gravel clean by themselves, and to a degree use the organic wastes as a source of nutrients.>
I am not sure what is causing this huge accumulation of waste in my gravel.
No amount of siphoning seems to decrease this amount.
<Put the filter in a bucket of aquarium water and leave it running, and then take apart the tank and give it a thorough clean. Return only so much gravel as you need to cover the glass.>
Ammonia and nitrites are both at 0.
What should I do?
<Clean the tank, and review the basics of setting up and maintaining an aquarium. Once you're happy you have them covered, go get some more fish, but choose something more suitable for a 5 gallon tank, such as a Betta or perhaps a few shrimps and small gobies.>
-Melissa
<Cheers, Neale>

Re: Excess nitrates problem  11/1/07
Hi again,
<Greetings!>
I understand that 5 gallons is difficult to keep balanced. I'm preparing a 15 gallon now...don't have room for anything bigger.
<Good. While 15 gallons is still on the small size, it's certainly much easier to maintain than a 5 gallon tank.>
My java fern is rooted to a piece of wood. I also have a piece of driftwood on which I am keeping java moss.
<Correct maintenance for both these plants. If placed in the substrate, they rot.>
My gravel is about 3/4 of an inch deep.
<Use less. In a tank without plants or an undergravel filter, you really only need enough to cover the glass. I prefer to use sand with Corydoras than gravel; you will immediately see changes in their behaviour as these catfish happily root about in a more natural way. Aquarium sand can be used, but non-calcareous smooth silver sand (silica sand) costs next to nothing and can be bought at any garden centre.>
I will take the tank apart and clean it as suggested. Should I empty out all the water as well when I do this?
<Yes. Of course, make sure the new water is dechlorinated and at roughly the right temperature for your fish, i.e., not too cold and not too hot. Corydoras panda (which I think you said you had) like water on the cool side: aim for 20-25C, but no higher and not substantially lower. Do keep the filter running in a bucket of aquarium water while you're cleaning the tank; otherwise, the bacteria will start dying, which is a Bad Thing.>
Thanks for the help.
-Melissa
<Good luck, Neale>

Bad link on your site... and FW algae, nitrification issue   10/15/07
Hello Crew member,
FYI, you have a nasty link on your site located at /diatomfltfaqs.htm. It is the 9th post from the top, titled ?Re: Diatom Filtration? and the link is <http://www/> http://www dot aquarium advice dot com/viewtopic dot php?t=3250. (link is retyped so to prevent you from accidentally clicking it)
The link attempted to install the following 3 viruses: Exploit-MS06-014 (Virus), Exploit-CVE2006-3730 (Virus), and VBS/Psyme (Virus) in rapid succession. My virus software stopped the attack, but my system was frozen for several minutes.
<Yikes... I see what you mean... Have removed this link. Thank you>
While I am taking the time to write you, I might as well ask a question. I have spent many hours reading your site and have asked a few questions in the past as well, and I must say that you people are the bomb.
<La bomba!>
Currently, I have a green water situation that seems to go against standard logic. In a nut shell, the problem worsens each time I vacuum the gravel or clean the filter. Several months ago the problem was not green water, but rather cloudy water. If I left the tank to its own (if I neglected it), it would clear up, but nitrates would rise as well to the point that water changes would have little impact.
<Mmm, you need/want more "filtration"... low/ hypoxic to no/ anoxic spaces...>
It is then that I clean the filter and/or the gravel to slow down the production of and lower nitrates, but that causes the water to turn cloudy. I try to keep the nitrates below 10ppm, but when water changes will no longer keep the level below 20ppm is when I know I need to clean the filter and gravel.
<Yes... a common situation>
After purchasing 2 pleco's who do a wonderful job of cleaning the glass, gravel and décor of all visible algae, the problem of cloudy water became a problem of green water, and boy is the water green. Visibility in the tank is about 4 inches, and it has been that way for about 2 weeks now.
I am at a loss. All water tests are currently and stay great with the exception of phosphates, which I have not tested because I use to use a phosphate buffer to control Ph so I knew the reading would be high. I have since quit using the Ph buffer and have let the Ph rise as a result. High or otherwise, phosphate levels have no impact on the cloudy/green water.
I have read so many of your articles and faq's that I feel like an expert on the subject, but something is amiss.
More info;
I can't keep plants because my silver dollars will eat them.
My tank is 75 gallons.
I have 4 silver dollars, 3 Corys, 2 bushy-nosed pleco's, and 1 blue ram. I wonder if I do not have enough fish to support the biology in the filter?
Is that possible? When I had many more fish I didn't have this problem.
I have an EHEIM Pro 2 canister filter running about 275GPH and it is full of bio balls that I am very careful to not tamper with.
<Good>
The tank has been running for about 3 years.
I use RO water treated with RO right (2dGH) and baking soda (3dKH).
Everything in the tank is plastic, or epoxy coated except 3 pieces of Malaysian drift wood.
<This, these should help>
No nitrites, no ammonia, Ph 7.6, (I prefer lower but cannot seem to keep it down without using phosphates), nitrates 5ppm at last check.
I need to get to the root of the green water. I have had aquariums for over 30 years, but never has issues like this.
I am trying to keep this short, so will cut it off here. If you need more info please let me know.
Best Regards,
Scott
<Not to make too much of a simple/simplified response sans explanation, but the "answer" to the situation here is more fine substrate... like another inch or so of gravel... or the addition of ceramic ring, sintered glass media... for the bioballs. This will shift more of nitrogen cycling to/back to denitrification... Bob Fenner>

Nitrite levels waaaaaaaaay high - ugh.  9/2/07
Neale,
<Kristi,>
OK - now I'm thoroughly confused.
<Pray tell...>
Regarding my nitrite levels - they were and still are reading 2.0 mg/L. I double checked the color card (API test) and that's what it is and has been.
<OK. Well, not actually OK, but OK as in I understand.>
Other levels are as follows: Nitrate ~10 mg/l (and on its way down),
ammonia 0, ph consistent at ~ 7.7.
<These are fine.>
Given that 1 m/mg./l nitrite is lethal and my fish are still alive, what is going on? The 35% water change yesterday didn't do a thing to reduce the nitrite 2.0 levels. The test kit suggests the following actions when initial levels are high:
<1 mg/l is a ball-park figure. It varies. 0.2 mg/l will kill Tanganyikan cichlids pretty quickly, while mudskippers (adapted to resting in burrows when the tide is out) will take levels of ammonia and nitrite much higher than most fish. So it varies. What nitrite does is stress the fish, damaging tissues and messing up its immune system. In the long term, a tank maintained at 2 mg/l nitrite is unhealthy, and the mortality of the fish will be high.>
1. Add a Nitra-Zorb to the filter,
<Waste of time.>
2. Add bacterial supplement to help speed the development of the bio filter,
<Waste of money, except perhaps in the case of BioSpira and Tetra Safe Start, which are "live" bacteria cultures. By contrast, filter-boosters and filter-aids have had very mixed reviews from aquarists, and are probably not all that useful.>
and
2. Add aquarium salt to reduce nitrite toxicity to fish while the natural filter is removing the nitrite.
<Possibly an option. The livebearers and glassfish obviously won't mind this at all.>
Question: Is adding *any* salt a good idea given I have an ADF and dwarf gourami? If so, at what dose?
<It's a case of "less of two evils". As a short-term supportive, salt has some value here. You don't need Aquarium Salt for this, plain non-iodised cooking salt will do just fine (this is sometimes sold as Sea Salt for example). Use small amounts at first, perhaps 1 gramme per litre. If the fish are basically fine, I'd back off using salt, and just cut back the food and let the filter develop speedily. Regular water changes will dilute the nitrite enough to keep the fish healthy, all things being equal. This is "cycling with fish" basically, and done properly, works fine. It's the old fashioned approach to be sure, and done badly ends up with a lot of dead fish, which is why so many books recommend fish-less cycling instead.>
What could be causing such high nitrite levels?
<It would appear that your nitrifying (ammonia -> nitrite) bacteria are all in good shape, but the nitrifying (nitrite -> nitrate) bacteria are for some reason not doing their job. Give it 2-3 weeks more and you should be fine. In the meantime, do everything you can to optimise conditions for the fish and the bacteria. You already have an alkaline pH and fairly high hardness, which is what the filter bacteria like (they HATE soft/acid water!) but they also need lots of oxygen, so check circulation of the water is adequate. Also make sure the filter is sufficiently large, and not filled with worthless rubbish like carbon. What you want is plenty of good quality biological filter media. Sponge and ceramic hoops are best, but filter wool will do too. Make sure the media aren't clogged up.>
Kristi
<Hope this helps, Neale>

The game plan. FW maint.  - 9/3/07
Neale,
<Kristi,>
All right, hours of reading/research on the WWM site and your expert advice resulted in the following game plan to address my issues. Could you please review and confirm that I'm not missing anything.
<Will do.>
1. Initially add sea salt (@ 1 gram per liter) for short-term detox of high nitrites. I'll use this only as needed for spiking nitrite levels.
<Yep.>
2. Feed only once per day for now,
<Correct.>
3. Hold off on gravel vacuuming,
<Do, don't do; it really doesn't make much difference. I find hoovering up the detritus with each water change is easier and less likely to uproot the plants.>
4. Add more gravel substrate (I currently only have 1 inch),
<Depends on what you have in the tank. If no rooted plants, then 1 inch is fine. Too much, even. You only need enough to cover the glass, and volume used for gravel is taking away volume of water. And the more water, the more stable the conditions in the tan. Lots of plants don't need gravel and prefer to grow on objects (rock, wood) for example Anubias, Java moss, and Java fern. On the other hand, rooted plants need about 3-4 inches. To some extent rooted plants (like Vallisneria, Amazon swords, etc) also need nutrients in the gravel too. I use pond soil, but others use laterite or fertiliser pellets they shove into the roots of each plant every couple of months.>
5. Replace current power filter with BIO-Wheel (I changed out the carbon filter three days ago before realizing I was throwing away the good bacteria - oops)
<OK.>
6. Add BioSpira to help establish good bacteria more quickly.
<If you want. At this stage it probably won't make a massive difference, because you have half the bacteria established already. But it won't hurt. Follow the instructions on the package carefully.>
7. Consider adding a small bubble wand to add more oxygenation (although I already have a bubbler water feature along with the power filter serving up to a 20 gallon tank). Would the ADF be ok with more water current, or should I hold off on the bubble wand?
<Ah, should be fine. But as I've said elsewhere, frogs and fish don't really mix. Frogs (generally) live in still or stagnant water where fish are unable to live. They can't compete very well in the wild -- fish simply eat frogs because they swim so much better. So to some extent this is a "suck it and see" situation; try it out and see what happens.>
5. Hold to weekly 50% water changes unless levels become dangerously high.
<You can't do too many water changes, so be flexible here. Provided the new water has zero ammonia and is of the same pH, hardness, and temperature as the old water, do as many water changes as you can.>
6. During water changes, treat "new" dechlorinated water with Ammo-Lock as well to address Chloramine issues.
<Yes.>
7. Eventually decide on algae control critters, but don't add until tank stabilizes.
<Algae control critters are a contradiction in terms. Adding animals to an aquarium increases the nitrates and phosphates, which increases the rate at which algae grows. Biology doesn't care if the animals eat algae or fried chicken, all animals are pumping out nitrate and phosphate. The only algae control that works is adding fast-growing plants. Vallisneria, hornwort, Cabomba, etc. Somehow, for reasons not entirely clear, these plants suppress the growth of algae, to the point where it stops being a problem. It sounds bizarre, but truly, you can have an overstocked tank but if there are lots of plants in there, at most you'll be wiping a little bit of algae off the glass once every six weeks. Quite how this works isn't clear, but it may be something to do with allelopathy, the ability of plants to (effectively) poison algae so that their leaves stay clean. There's so much about plant physiology we don't understand, but this is one aspect we can put into use in the aquarium.>
Hmmmm...anything else? Oh yeah...more patience.
<Hah!>
This fish thing is becoming addicting!!!!!! Thanks again to you and the WWM site for all your guidance and info.
Kristi
<Happy to help, Neale>

Water readings always zero, Not a bad thing 8/29/07
I'm so sorry for having yet another question. I love your sight, but for everything I learn I have questions. I find the answer and then that leads to more questions.
<The learning process.>
This concerns water quality. I've got 5 aquariums. I split up the percentage and do daily water changes vs. a large weekly water change. The fish don't even notice as it's syphoned out and slowly pumped back in with a tiny pump from the stored aerated well water. I've done this for over a year and the fish are very healthy.
In researching your site for ideas in setting up a drip system (been wanting to do that for awhile) I came across a references stating low level nitrAtes were needed in the water. It happened to be talking about saltwater tanks. Is that true for *only saltwater?
<In some very specific situations this is mostly true, heavily planted tank in FW and some clam tanks in SW will benefit from low levels of nitrates, but for most aquariums if your nitrates are 0 then be happy.>
My ammonia, nitrItes and nitrAtes have literally always read '0' on my FW tanks (cycled). All the references about nitrAte always say to keep them under about 20-25 for FW fish.
So....does that mean I'm *supposed to have at least some nitrates in the water? I always thought I was doing the right thing but I've found sometimes I try too hard and come to find I've over-done it.
<0 is best in most situations, just most people are not willing to do the amount of water changes you do to achieve that.>
Now I wonder if there's some electrolyte or mineral or some weird alien nutrient I hadn't considered that I'm depriving them of by keeping their nitrates at '0' instead of letting them build up to 10 or 15 ppm.
<Nope>
I'm so sorry if this is a ridiculous question, I've been pondering it for 3 days. It might help someone else to know this, too.
Thank you for your endless patience. I'd gladly join your team and answer questions but I feel I know so little compared to your crew.
Mitzi
<Don't underestimate your knowledge. When you feel ready, drop a line, we are always looking for people who are willing to help.>
<Chris>

High Nitrates  8/27/08
Hi there Neale (?),
<Hello Lisa,>
Hope you are well.
<Can't complain.>
Could you please help me out? In my community tank, I've been reading high nitrate levels for the last few weeks. This tank is a 30 gallon hex, with 5 guppies, 1 black skirt tetra, 1 giant danio, 1 zebra danio, 2 Plecos, 2 bumblebee cats and 5 Corys (many bottom feeders I know! I LOVE them - they are such happy creatures). The change has come about in the last few weeks, as I have made an effort to feed the cats a few shrimp pellets and an algae wafer or two on a nightly basis - I've been doing reading on your site and I believe it was Fenner that recommends feeding the catfish "meaty foods" twice a day. (Oh and I did add the bumblebees to the tank about 2-3 weeks ago (Microglanis iheringi).
<Define "high" nitrates. Anything from 50 mg/l downwards is fine, and even 100 mg/l is unlikely to cause problems.>
I realize a high nitrate level is due to excessive food decay - correct? Nitrites and ammonia levels are 0. pH is on the high side - 7.6 (I usually keep it neutral at 7.0 - out of the tap it's 7.2).
<Nitrate comes from the end of the biological filtration process. Ammonia (from the fish) goes to nitrite, and nitrite goes to nitrate. Water changes are used to dilute the nitrate. Since nitrate is (basically) non-toxic, there's no need in freshwater aquaria to worry about it most of the time. Things are different in marine aquaria, and to some extent in Rift Valley cichlid aquaria, but for standard community tropicals you can usually ignore nitrate. So long as you aren't grossly overstocked/overfeeding and you do the 50% water changes each week, it should stay at a safe level automatically.>
I've been doing partial water changes 2-3 times per week to keep the levels down.
<OK. But how *much* water per change? Aim for 50% a week, one way or another.>
I'm running a Penn Plax canister filter with a capacity of 65 gallons (I realize it's turnover that's the important factor). I just ordered a large bubblewand to provide both additional aeration and get the waste and excess food up and into the filter intake.
<Hmm. Not sure how the bubble wand will help here, but OK. Neale's golden rule for spending money is always buy another filter when you have spare cash. Everything else is niceties, but a filter is always money well spent. Even a cheap little internal box filter jammed into the corner and filled with ceramic media or filter wool will do more good than a dozen bubble wands.>
I wanted to move one of the Plecos (5-6" in length) over to the Mbuna tank however that nasty Chinese Algae Eater is in there and I don't want him to latch onto him.
<Hah! Plecs and CAEs usually coexist, and I've mixed them together myself. Does depend on the relative sizes of the fish, and how much cover the Plec has (it rough aquaria they tend to hide during the day and feed only at night). To some degree, CAE behaviour depends on diet: adults are more or less omnivorous rather than herbivorous, and should be provided with a mix of green vegetables as well as opened mussels, bits of prawn, and so on.>
What do you recommend in this situation to get the nitrate levels down?
<Tell me what the Nitrate value is first, and then I'll comment. If it's below 50 mg/l, don't worry about it. Also check you tap (faucet) water supply. London tap water for example has 50 mg/l anyway, so aquaria in London will have nitrate levels above that. Doesn't cause undue problems most of the time. Fish adapt to even sub-optimal conditions, and provided everything else is basically sound, nitrate is a relatively trivial issue.>
As always, thank you!!
<Not a problem.>
Lisa in Natick, Mass.
<Neale in Berkhamsted, Herts.>

Re: High Nitrates – 08/27/07
Thanks again Neale.
<Hello Lisa,>
As you say, I did note on the FAQ that nitrate problems refer mostly to marine aquariums. I do not want to take advantage of your service so I will always do the research before asking a question. I so appreciate this great service. And thank you for your patience. I can sense a bit of humor in your responses - I'm not sure you're rolling your eyes at my questions - but I'd say it's definitely a possibility! :-)
<More than likely, yes...>
My concern with the nitrates is the change in readings (although the fish are not displaying stress). I usually receive 5.0ppm ratings for all three tanks (I apologize for not providing a reading). However, in this particular tank I AM overfeeding hence receiving a reading in between 40-80ppm (brought down to 40 with 25% water changes a few times per week). I believe I've sufficiently run out of real estate concerning number of fish also. There's even waste lying on the substrate (Plecos). I will begin doing 50% changes regularly on the weekends.
<Solid waste -- faeces -- really aren't a problem, especially not from plecs, which are herbivores. While unsightly, faeces contains little by way of toxins. Fish dump their "toxic waste" across the gills and in the urine, as ammonia. Neither of these sources is visible. This is why biological filtration is so important. Turnover is also important. For standard tropical fish (guppies, barbs, etc.) you need a filter providing at least 4 times the volume of the tank in turnover per hour. For big fish, like plecs and goldfish, 6 to 8 times turnover is in order. That's how you decide on whether or not you have enough filtration, though obviously nitrite test kits can be used to directly measure your success at managing the nitrogen cycle.>
I must have sensed "Neale's Golden Rule" for subsequent to writing my note yesterday, I installed a powerhead with a filter cartridge for added filtration - I will add a bit of carbon and bio media too.
<Skip the carbon, and double the biological media. Carbon provides a questionable service in a freshwater fish tank. But biological media is ALWAYS useful.>
I changed the canister's filter media too (except for bio media). Bubblewands are for wimps - noted. :-)
<It's not so much air stones and whatnot are for wimps, it's just they're not very good value in terms of what you get in return. The only time I use air in aquaria is for powering box filters or, on marine tanks, for skimmers. I just don't see much use for them otherwise. This isn't to say you should use them, and if money is no object, they certainly add a nice touch to the aquarium. But there are better ways to spend your money if you want sheer improvement in water quality.>
I will stop loving my fish with food and resort to the old feeding routine supplemented with a shrimp pellet, algae wafer or fresh veggie once or twice a week although seeing those bumblebee cats scoop up a pellet at the speed of light and the Cory feeding frenzy is quite fascinating!
<Indeed! You're talking to a catfish enthusiast, so no question, they're among the most fun fish in the hobby. Cichlids obviously win out when it comes to intelligence, but if you want "weirdness" (as Calvin & Hobbes might say) you gotta go with catfish.>
The CAE came as "a gift" as part of the Mbuna package. He IS fun to watch - the Mbuna chase him around a bit but if this guy latches onto my pleco there going to be hell to pay!
<Agreed. I kept one in 200 gallon tank with Central American cichlids. Worked quite well. There was also a gibbiceps catfish in there, and they all seemed to get along fine.>
The pleco I'd like to move into the tank is about 5 inches long, the CAE is about 3 inches.
<Sounds a reasonable gamble. I'd try it out and see what happens. The CAE couldn't kill the Plec in one day, so it should be apparent if one or other fish is being bullied long before there were problems.>
I do not have sufficient hiding places for him as of yet in the Mbuna tank however I'm going to decorate the tank with a great deal of rock next weekend.
<Plecs love terracotta flower pots, so providing hiding places shouldn't be hard.
Perhaps I will move the pleco in there once the aquascaping is complete. I'll place a bit of driftwood in there too as he really likes it.
<It's more than "liking", they eat the stuff too. While common Plec species can't digest wood (only "Royal" plecs, Panaque spp. can do that) they do seem to use wood as a source of dietary fibre, and it keeps them healthy.>
Do Plecos "feel" crowded - am I stunting his growth in the 30 hex?
<Quite possibly, yes. 30 US gallons is rather less than what I'd recommend for a common Plec. Even twice that wouldn't be exactly generous.>
Maybe I should just leave him where he is? I know Plecos can get huge in the wild and even in captivity...
<The standard Pterygoplichthys species get to around 40-50 cm in the wild, but there are other plecs that get twice that size. I've seen photos of as-yet undescribed Loricariid catfish literally the size of a child. There's a great You Tube video of a *school* of wild plecs in a Mexican lake, and it's quite something to see this huge mass of giant catfish scooting about like overgrown Corydoras. Sometimes, aquarists don't realise how different their fish behave in the wild.>
Thank you Neale!
<You're welcome, Neale>

Nitrate in freshwater Eclipse 12 system – 08/11/07
I have written off to Drs. Foster and Smith and That Fish Place but only received the pat answers which did not help me at all. I've seen your threads so thought I'd try you all.
<OK, Jeanine, fire away.>
I have a Marineland Eclipse System 12, freshwater, that has been up since January. I do weekly 25% water changes and vacuum the sand bed which is about 2 inches deep. I run my tank light about 7 hours a day. A month ago, I began noticing some of the brownish/red colored algae growing both on tank ornaments and on the live plants and when I checked nitrates, they were around the 40 or more mark.
<Right, you have a 12 US gallon tank, which isn't much at all. So by any standards you need to handle this tank extremely carefully if you want it to be stable. That said, nitrates at 40 mg/l are fine for most freshwater fish. Local water in London is around 50 mg/l right out the tap, and people keep fish with this stuff fine. Sure, there are some nitrate-intolerant fish, like Tanganyikan cichlids, but the basic stuff like neons and guppies generally couldn't care less.>
After doing reading and checking, I decided I had too many fish - 4 Cory cats and 5 dwarf neon rainbows, so I donated the rainbows to an LFS reducing the fish to only 4.
<The 4 Corydoras would be fine, but the rainbows aren't "overstocking" the tank, but just the wrong fish for such a small aquarium. They're hyperactive creatures. I'd sooner go with glowlights, neons, and other inactive small tetras when working with small (lengthwise) tanks.>
At the time, I had been feeding the fish daily, so I changed to every other day feeding so I am definitely NOT overfeeding. I feed frozen blood worms one day and also Hikari sinking wafer for catfish the next feeding. Oh, I also checked my phosphates and they are around 0.
<Now, frozen foods are great, and bloodworms low in proteins (something like 5%, check the package) so far less polluting than the same quantity of flake. People often forget that it isn't how much food you put in the tank that matters, but how much *protein*. That's why you can stick a head of lettuce in an catfish tank and let them graze away for a week, and yet the impact on the nitrogenous waste levels will be minimal.>
I did a massive 4 gallons at a time progressive water change sequence until I got the nitrates down below 5. I always make sure the carbon filter pad is clean (in tank water) and I even rinse out the BioWheel in tank water to remove excess buildup (if there is any).
<I say this twice daily, but carbon pads are useless, or at least, don't do any of the things aquarists think they do. Carbon doesn't remove nitrate and carbon doesn't reduce water pollution. All carbon does is remove dissolved organics, and if you're doing 50% water changes weekly (as you should be) then there won't be any dissolved organics anyway. So throw out the carbon, and replace with more biological filter media, which *will* do something useful. Corydoras, by the way, love big water changes, especially if the new water is slightly colder than the old water. If you're lucky, they'll spawn!>
Okay, so I've done everything I know to do so now that I've reduced the nitrates and am not overpopulated or overfeeding, surely the nitrates will not start going back up quickly. Well, within 3 days of doing the water change/vacuum, the nitrates were already back up to a good solid 5 ppm color so they are obviously rising.
<Nitrates are good in some ways, because they show the biological filter is doing its job. Don't worry about them. As I said, 50 mg/l is harmless in most cases, and even 100 mg/l won't cause major problems.>
I have read that BioWheels cause higher nitrates but that is the filter on the eclipse system and no one says much about freshwater nitrates and BioWheels in their articles.
<All sounds like rubbish. No filter can "make" more nitrates than another. Assuming you have biological filtration equal to the loading of the tank, each milligram of protein the fish eat will end up as exactly the same amount of nitrate, whether you are using a sponge filter, and undergravel filter, or a trickle filter. The only factors that moderate this are plant/algal growth (these use up nitrate) and denitrification in anaerobic sediments (where nitrate is broken to nitrogen). This latter is uncommon in freshwater tanks.>
I want to keep the nitrates at a lower level so the algae will not get a major foothold again.
<Non sequitur. You can have 100 mg/l of nitrates and no algae. You can also have 5 mg/l nitrate and lots of algae. Algae is a problem where a tank is "unbalanced", that is, there is an excess of light (especially sunlight) but not enough plant growth. Algae will grow more quickly if there's lot of nitrate, yes, but even if there isn't, algae can grow pretty well too. Add some live plants that grow rapidly. Vallisneria, hornwort, Cabomba, and Elodea are all good. Make sure they have lots of light. Honestly, once established, you'll be down to scraping algae once a month, if that. It's pretty amazing really. The mechanism isn't clear scientifically, but allelopathy may be a factor. Slow growing live plants, like Cryptocorynes, Java moss, Java ferns, Anubias, etc have no effect at all, by the way.>
How can I keep the nitrates lower - I will continue my tank maintenance and weekly 25% water changes, but I don't want to have to continue these huge progressive water changes every week to lower the nitrates.
<Forget about it. Too much work, not enough reward. Weekly 25% water changes aren't "huge" by the way, they stingy. 50% weekly is widely accepted nowadays to be a good baseline. The old idea that "old water" was somehow better for the fish has been thoroughly discredited.>
I find it hard to believe that 4 Cory cats with live plants and no over-feeding and regular weekly tank maintenance still generates such a quick nitrate rise. My only
thought is that it must be the BioWheel, but I'm not sure at all and don't know what to do about it.
<You're fine with the fish you have. Add half a dozen or so small, inactive tetras like neons, and maybe a handful of algae-eating shrimps for fun, and you'll have a nice little tank. Algae isn't the enemy by the way. If your fish breed, it becomes live food, and shrimps especially seem to eat nothing but algae and the microbes living amongst it. Algae is part of the natural world, and the only places you don't want it are the front glass and on the leaves of the plants. Everywhere else...? Get over it. Let the algae do it's thing. It's fish/shrimp food of the best sort and a valuable source of vitamins for them. Most fish will peck away at it occasionally, like cats nibbling on grass. But seriously, once you have rapid plant growth, the algae becomes a trivial issue.>
Thanks so much,
Jeanine
<You're welcome, Neale>

Re: nitrate in freshwater Eclipse 12 system – 08/11/07
Neale,
What an AWESOME response. Thank you for taking time to respond so thoroughly. Yours is the first real answer I've gotten from anyone. I really don't see algae as the 'enemy', but obviously didn't want it overtaking the tank and plants and things. I will get some of the plants you recommended and see if that takes care of things. I have about 6 plants in there now, but don't think any of them are what you recommended.
<Do some reading on "aquarium plants", "allelopathy", and "algae" and you'll get lots of information about how people think the system works, what plants work best, and so on. It's controversial, but I'm sold. When I tried it, it worked.>
If I do get a few neons as you suggested, is there any particular brand of flake food (which I assume they eat) that is not too high in protein? I have the Hikari micro pellets if they would work.
<Should be fine. The secret to feeding fish is variety. Don't buy big tubs, but small tubs of flake or pellets, so you can regularly skip between brands. Algae-based flake foods are probably the best diet for most small fish. Some days, don't feed your fish any flake foods, but instead put in something like a thin slice of cucumber, some sushi Nori, or an algae pellet. Frozen foods are always good, but live daphnia or whatever are best of all. Raid the kitchen: bits of raw prawn or fish meat are often enjoyed by small fish. All sorts of greens can be pressed into service. As with anything in life, a little of everything is better than just one thing, however good.>
Thank you again,
I am really grateful,
Jeanine
<You're welcome, Neale>

FW filtration, lowering pH though using aragonitic mat., and NO3s in an Af. cichlid set-up   6/20/07
Hey guys. In your opinion, regarding freshwater tank setup, do you think it would be equally as effective to put two Aquaclear 500 HOB filter on a 125g opposed to one canister and one HOB Aquaclear 500?
<Mmm, possibly... though I would in either case, locate the units at either end of the system, clean only one per week during other regular maintenance... water changes, testing...>
I am setting up a tank for a friend and through my past experience I really think that the HOB's do a better job at filtration. Currently on my 75gal I have one of each
(canister/hob), what do you recommend for a large tank like this?
<For what sorts of livestock? If this were a planted tank, I'd opt for the mix of units... for Af. et most Cichlid set-ups the two outside power filter hang-ons if these were my only choices>
Also, on my Malawi tank I put roughly ten pound of crushed aragonite as my substrate to buffer the ph.
<Good>
In the beginning, my ph was steady at about 7.9-8.0, now i notice that it has gone down to about 7.5-7.6, what could be the problem?
<The more-soluble parts/faces of this substrate are gone... a good idea to refresh (replace, add to) occasionally... every three months or so in this proportion of sized tank/gravel>
Also, my nitrates are constantly at 40ppm even shortly after a large water change on my 75gal.
<Too high... a good idea for you to read here: http://www.wetwebmedia.com/FWSubWebIndex/fwmaintindex.htm
See the yellow tray, Nitrates below?>
My bio load is only at half of it's maximum plus the fact that it's well over filtered with filtration rate of 850gph. I have about ten cichlids and one catfish with a total of about 40 inches so I guess I probably have about 30 more inches left to stock (going by general rule of thumb....1" per gallon). Any ideas as to what may be the problems here?
<All sorts>
Thanks in advance for your time and help!!!
Jason
<Read on my friend, read on. Bob Fenner>

Re: FW NO3   6/20/07
Thanks Bob. The link you gave me in the last email was targeted toward saltwater (even though it claims to be freshwater nitrates),
<Ah, yes... we don't have enough mat. as yet to separate. Many of the principles apply to both...>
and did not answer my questions. The article told you "generally" about nitrates with no information pinpointed to my current situation. I also checked the FAQ's and no one
seemed to have the problem I have without probable cause. I have no probable cause, so with your several years of experience do you have any idea what the problem may be?
<Yes... a simple balancing of a series of variables/equation... More food, metabolism on one side... not enough anaerobic digestion by certain groups of microbes on the other... And insufficient nutrient export otherwise... Again... please do re-read where you were referred to... the linked files at top.... Your options are simple to delineate... less food, esp. of a proteinaceous nature, less livestock... more anaerobiosis... DSB likely, perhaps specialized media (e.g. sintered glass, ceramic beads/macaronis... made for this...) and the export... more water changes, the use of chem. filtrants, purposeful photosynthesis... the DSB, plants likely in a tied in live sump... All gone over and over on WWM...>
I vacuum once every two weeks along with 20% water changes. My bio load is only at about half of the maximum it should be
<... not useful thinking... Try covering your "good eye" with your hand, walking backward for a minute... Really>
for a 75gal tank. I have an Aquaclear 50 HOB and a Filstar XP3. I have bio rings and stars in both filters but no BioWheel so the bio filtration is constantly under water with no air hitting. I use no supplements and feed very lightly.
So clearly Bob, can you see any probable cause here? I don't, I need help.
Jason
<Read my young friend, read. RMF>
LOL, thanks for answering my simple question Bob.
<Welcome... RMF>

Nitrates and Green Water   6/10/07
Hello!
<<Hello, Vicki. Tom here.>>
I've been reading through your FAQs on green water, since my tank has a sudden and terrible case of it. All of the responses stress the importance of testing the nitrate and ammonia levels in the tank. My question is this - is there any way to lower ammonia or nitrate levels without increasing the number of water changes? I'm worried that if I change the water any more frequently, I'll destroy the beneficial bacteria and have to cycle the tank over again.
<<Vicki, provided the water changes are performed correctly, there’s little chance that these will harm your bio-colonies which are housed primarily in the filter media. That said, you can also change your water too frequently which might seem at odds with what your research has turned up. We’ll take this up later in your post but for the time being, think in terms of the quantity of water changed versus the frequency of the changes.>>
Here's a little background:
I have a 10 gallon freshwater tank with 4 mollies, 2 guppies, 3 tetras, a kuhli loach, a horsehead loach, a Corydoras catfish, and a snail.
<<Off the subject just a bit, Vicki, but your ten-gallon tank is over-crowded with incompatible species. For example, Mollies prefer hard, alkaline water (consider these to be brackish water fish) while Guppies prefer soft, acidic water. Same goes for your Loaches. As an aside here, Corys are highly social little critters that really do best in groups, not alone.>>
The PH is stable at 6.9 and the temperature is 78.
<<This isn’t too bad for any except for the Mollies.>>
Up until three weeks ago, I had a goldfish instead of the mollies. He died, I replaced him with the mollies, and within a week, the water was cloudy and green.
<<Skip Goldfish until you’re in a position to get a much larger tank, 30 gallons or better.>>
First, I tried reducing the lighting (the lights are now on about 1 hour/day).
<<An appropriate move here, Vicki.>>
Then I tried adding about a tablespoon of aquarium salt (replacing it proportionally after water changes).
<<The correct methodology but unnecessary. The Cory, Guppies and Loaches don’t appreciate salt in their water and, under different circumstances, the proper salt to use for Mollies is Marine salt, not aquarium salt.>>
I also added plants - I now have four of them.
<<Good move for several reasons.>>
When none of that worked, I tried taping a piece of water to the outside of the tank on one side, to reduce the small amount of sunlight that comes in. For the past two weeks, I have been doing 20% water changes every two days.
<<Let’s pick up on this once again. The green water you’re experiencing is the result of an algae “bloom” likely caused by an excess of nitrates and/or ammonium in the water. (The reason for testing for nitrates is pretty straightforward since these are largely responsible for the nutrients needed for plants/algae to thrive. Checking for ammonia/ammonium may be a little less obvious but ammonia (NH3) exists as ammonium (NH4) at lower pH levels. This is also somewhat temperature-dependent but pH is the bigger factor here. Since ammonium is also used by plants and algae – in some cases before nitrates are – this explains why this test is also important.) You’ve got a lot of life going on in a small environment which contributes to a proportionate amount of waste from the fish and, potentially, uneaten food. In a stable tank, a 20% water change once a week, or even two weeks, would be sufficient. In your case, however, I would recommend a single, “massive” water change as opposed to multiple, smaller changes. My rationale is that a 20% change still leaves ~80% of the suspended algae and nutrients behind. These increase rapidly over a couple of days and you’re back at “square one”, i.e. the reason why the smaller changes aren’t really correcting the problem. One massive change on the order of 80%-90% will dramatically reduce both the algae and nutrients and allow your other measures to take hold and combat the algae growth.>>
I've changed the filter cartridge once, but left the plastic sponge in, which is supposed to house some of the beneficial bacteria.
<<You haven’t specified the size of your filter, Vicki, but it’s possible/probable that it’s smaller than what is needed based on your stocking levels. Good for you, however, that you left the sponge in place. This is where the lion’s share of the bacteria reside.>>
I've also thoroughly vacuumed the substrate. I used to have a small amount of algae on the tank decorations and glass, but this has all died while the green water problem continues to flourish.
<<Part of your plan is obviously working, Vicki. We just need to get rid of the suspended stuff.>>
I admit, I haven't purchased a nitrate or ammonia test kit, yet. They seem fairly expensive and I'm not sure how the nitrates or ammonia could be high after all the water changes I've done.
<<You don’t need to start with an entire test kit if it’s not in the budget right now. Individual kits for ammonia and nitrates, alone, can be purchased from virtually any LFS in your area. It’s a good bet that you could find these even cheaper online. As for how these compounds could still be high, simply put, you have more going in than coming out. Algae is exceptionally prolific and you’ve got plenty of sources of nutrition in your tank right now.>>
If the levels do prove to be high, should I change out even more of the water?
<<Yes, but by quantity, not frequency.>>
Won't that kill off the beneficial bacteria and cause my tank to re-cycle?
<<Not to any significant degree. Fish rid their body systems of ammonia through specialized membranes in their gills, not through their waste. In other words, your fish will be providing the bacteria with a pretty steady supply of ammonia even after a large water change.>>
Thanks very much for your help!
- Vicki
<<Happy to do so, Vicki. You may want to re-evaluate the size of your filter, as I mentioned. Within the realm of common sense, of course, it would be pretty hard to over-filter your aquarium as you currently have it set up. Best of luck to you. Tom>>

AZNO3 in freshwater aquarium  2/19/07
Bob, can AZNO3 be used in a fresh water aquarium without a protein skimmer to reduce nitrates? Thanks Bob P.
<Mmm, can be used... (http://www.marinedepot.com/aquarium_additives_azno3.asp?CartId=)no need to use a protein skimmer in/with FW systems (are problematical due to physical/chemical properties of phobic molecules in such)... but there are many other "more dependable" means of nitrate reduction... in FW... covered on WWM. If you purchase this fine product, make sure it is "fresh" and store in a fridge... and use w/in two months... Bob Fenner>