Please visit our Sponsors
FAQs about Toxic Water Conditions: Nutrients

Related Articles: Marine Toxic Tank Conditions , General  Marine Maintenance,

Related FAQs: Toxic Situations 1, Toxic Situations 2, Toxic Situations 3Toxic Situations 4Toxic Situations 5, Toxic Situations 6, Toxic Situations 7, Toxic Situations 8, Toxic Situations 9, & FAQs on Toxic Water Conditions by: Unknown Causes, & Endogenous (from inside, e.g. Internal, Organic Causes): Foods, Venomous/Poisonous Tankmates, Wipe-out Syndromes/New Tanks e.g., Exogenous (from outside, External, Inorganic, e.g. Metals), Marine Algaecide Use/Chemical Control, Toxic Copper Use Situations/Troubleshooting, Insecticides, Cleaners, & Troubleshooting/Fixing,

Mmm, not nitrate by itself generally, unless it's REALLY high in concentration... but ammonia, nitrite... at any concentration, particularly if the pH is high... and phosphate... and many more organic compounds for which there are no tests. 

Shop......    High SW NO3    ?   7/31/16
Also bob a shop paid me good money toco e in and sort there marine system out , which I've done in the way of quality and choice, I don't like the set up loads of sponges etc
Now this harbours nitrates to about 80
<Yikes; much too high>
I'm not far from walking out because they think that's acceptable , I as to have full running of everything
I got to do a wc , why nitrates are high
There fine dyla been like that for years !!!!!
Not in my last shop I was there rival and my fish health was better can you confirm 80 is over the top they say it hi k to much about nitrates
<N03 by itself is not "the" issue; what it portends is. PLEASE DO READ on WWM RE>
Dylan Mason

Reef tank crash and fish recovery?   2/23/11
Hello Crew, this is a wonderful and informative site that I have used many times for quick relief. Unfortunately I have an issue for which I have not found any guidance. Over the last two days my tank has
seriously crashed and I probably caused it, and made it worse every step of the way. After a failed experiment with some oysters and clams in my refugium, I tested my param.s and discovered my nitrates were off the chart and my ammonia was creeping up to .5 ppm, most likely from the death of the oysters.
<These have hopefully been removed>
Thinking this presaged the end of the world I rushed up to the local PetSmart and bought a bottle of Ammo-lock.
<Oh... no>
I dosed my tank with far less than the recommended dosage but on testing my param.s again in the morning the ammonia now was starting to hit the top of the scale.
So, in even more of a panic I went to the local LFS and got a bottle of Micro-Bacter 7 (MB7) and added the recommended dosage to my tank. Almost instantly I started getting a bacterial bloom and by the next morning all my Acros and Montis had shed their flesh. By the way, my tank has very high (0.5ppm) phosphates, but in my situation this actually is a good thing. My tank is a 300G Rubbermaid container in my basement.
Algae only grows on the sides of the tank and my tangs and angels graze on it all day.
<I see this>
I guess my first question is what did I do to my tank by combining those two products,
and my second question is what can I do to help my fish recover?
<Time going by... IF they are suffering "too much", either a massive water change out or removal to another established system>
They are all hanging down around the bottom (but not laying on the bottom) or hiding in the rocks.
I haven't told my wife this yet but I think some of them might be blind.
I've started up another tank in which to move them, but it's not ready yet.
Would putting them in freshly made saltwater be more shocking than letting them ride this out?
<Can't say from here. Likely a close call/difference>
Thanks for any info you can share, I promised the woman I would write to you.
Tank info:
300G Rubbermaid container
100G Freeland stock tank sump
65G Freeland stock tank refugium
Reef Octopus ginormous protein skimmer
1400 watts mixed metal halides and T5s
Current nitrate: 80ppm
Current nitrite: 1ppm
Current ammonia: UNKNOWN because Ammo-lock screws up the reading
Salinity: 1.26
pH: 8.11
Alk: 11 dkH
<No more Ammo-lock, nor bacteria, nor feeding of any sort... Bob Fenner>

Queen Angel - High Nitrates - 10/24/09
<G and K>
We have a beautiful Queen Angel that has been in the tank for about 2 years. We were lax in making water changes and ended up with very high nitrate levels. All of a sudden, our angel was hiding in the bottom of the tank in the corner and stopped eating. That's how we found out about the high nitrates. We have since started performing water changes and the angel is starting to swim around the tank. The weird thing is that her mouth seems to be locked open.
The angel is starting to try to move it, but it's not great. Can very high nitrate levels do this to the angel?
<Yes... not just the NO3, but what actually lead to its concentration>
I thought that nitrates usually don't hurt fish. The angel is also being a little twitchy with the eyes and the swimming. Could this be something other than the nitrates?
<Is co... related. Doing what you can/will do to rectify the Nitrate should solve the Angel's health>
We look forward to your reply.
Greg and Kirsten
<Bob Fenner> 

Re: Queen Angel - High Nitrates - 10/25/09
Thank you Bob for your quick response. We have another question. Our tank
is a 76 gallon reef tank
<Holacanthus ciliaris needs more room than this>
and we have been doing a 15 gallon water change every 2-3 days for the last two weeks without much improvement.
<... this won't "do it">
We use RO water and have tested the water with the reef crystals and have a 0 reading for nitrates. Shouldn't we have seen a better result by now? Thanks for your help.
Greg and Kirsten
<Sorry I didn't refer you before. Please read:
and the linked files above. Bob Fenner>

Hippo tang not eating! Deli time, high NO3  - 10/24/09
Hi all,
<Reuben... one of my fave sandwiches BTW. Extra 'kraut please>
Firstly just like to say that your web site is a great resource and has helped me loads in the past!
<Welcome... and sharp mustard galore>
The problem I'm having I couldn't quite find this time though so am asking myself this time.
I've had a 65 gallon tank now for just over a year and a half with 1 hippo tang about 4 inches long now, a yellow about 3 inches, a Sixline wrasse and two ocellaris clowns.
The tank has remained with the same inhabitants and live rock arrangement with a couple of soft corals for the best part of a year with no real problems though I have lost a couple of snails and my cleaner shrimp did go missing about 6 months ago never to be seen again!
My problem is about 5 nights ago I returned form work to find that my Hippo tang was no where to be seen at feeding time (he normally will always come out and actually will play 'tug o war'
with a piece of dried seaweed if you hold it on the surface of the water)
after a look around I found him hiding in his little rock space or 'home' at first I thought maybe he's just a bit spooked from a 10% water change I did the night before but he didn't come out all night, I managed to get a good look at him using a combination of peeking through the gaps in the rock and hanging a mirror down the back of the tank and he looked fine, no skin damage ich or anything similar, his eyes looked ok and he was flapping his fins about like normal, so I was a little bit puzzled.
Anyway 3 days later and he still hadn't really moved so I headed to my LFS to get some advice and after explaining the situation they suggested that the power balance may of swung in the Yellow's favour (as with the Hippos absence he was looking a bit more dominant) and that the Hippo has been stressed and/or scared so they suggested getting him out of the gap to try to feed him, unfortunately I don't have a QT tank and don't have the money to buy another setup at the moment
<Solution: Catch the Yellow Tang and place it for a few days in a floating plastic colander in the tank>
so for now I have put him in a home made large 'breeder box' within the tank, since then he has pretty much (apart from when I first put him in he was swimming around a bit)
stayed in the corner of the box
<Move this Paracanthurus out of here>
just flapping his fins sometimes calmly other times fast like he's trying swim away and hide, I've put in a bit of flake food (which is used to eat all the time almost 'stealing' from the clowns), a few live brine shrimp which he definitely normally eats and hung a piece of dried seaweed in and he has completely ignored all of it, in actual fact the only reaction I did get is if I move the box about he loses colour and turns white (it returns shortly afterward).
I'm getting worried about him now the last time I saw him eat anything was about 5 days ago and he's starting to look a bit skinny and his stomach has now got a small 'pinches' on either side.
Anyway tank parameters are,
Ammonia 0
Nitrites 0
Nitrates around 80-100ish
<... likely the root of the issue here. See WWM re NO3... act>
(this I know is too high and have had trouble with them in the past getting them down to 20ish) had a suspicion they may have crept back up recently as
my tank has had a bit of an algae bloom so will try and reduce these.
Don't know why it hasn't affected the corals and other inverts on LR though they all seem fine.
Ph around 8.2
Temp around 78ish
SG is 1.025
Equipment is a canister filter, protein skimmer and two powerheads to increase flow inside tank.
Please any advice will greatly appreciated he's my fave fish and has so much personality, I hope I don't lose him.
Many Thanks,
<Get going Reuben. Bob Fenner> 

Ammonia Spike!...Glass Cleaner The Culprit? - 02/16/06 Hello again WWM! <<Hello Derek>> Thanks for the quick reply. <<You're welcome>> My tank is still experiencing that problem though, but now, I believe it's the ammonia that is killing the fish - it has risen to 1.0 ppm.  So my question is, what is causing the ammonia spike? <<All you did was plumb in a refugium with sugar-fine DSB?  Appears to be something else a work here...you haven't medicated this tank have you?...added anything besides the 'fuge/DSB?...any questionable tank decorations?  Just fishing, but seems maybe something has wiped out your nitrifying bacteria...wait a minute...you didn't happen to "replace" a bio-filter with the refugium did you?>> I did a decent job of rinsing the new aragonite (CaribSea brand); I rinsed it in small amounts in buckets few times until the water lost that milkiness to it. <<Takes quite a bit of effort to rinse clean these fine grades of sand.>> Could it be the sand or something else like the new refugium itself? <<Possibility of an introduced contaminate, yes.>> I talked to the guy who made it for me, and he claims that glass and silicone are kosher and that they shouldn't be causing my spike. <<Am in agreement...but was it possibly cleaned with an ammonia based cleaner (glass cleaner) before delivery to you?  This could explain the ammonia spike.>> I've been trying to combat the ammonia; I've done two 20% water changes over the past three days, and I've been adding Aquascience's "Ultimate" water conditioner (this conditioner has been an effective way to temporarily reduce ammonia from past experiences), but neither of these have affected the ammonia level.  How much and how often should I be doing water changes until my levels go back down, or is there something else I should do? <<You need to isolate the source.  Ideally you can relocate your livestock while you do this, if not, remove the sump/'fuge from the system and do a 50% water change to reduce the ammonia level.  Continue to monitor this and do water changes as necessary.  If the sump/'fuge is the source of ammonia the tank should recover relatively quickly.  If not, you'll need to remove the livestock and let the ammonia cycle out (as in a new tank cycle).>> Thanks again! Derek <<Regards, EricR>>

Fluval Emergency Hi.  I think I may have made a catastrophic mistake this morning.  I walked by my 55 Gallon FOWLR tank this morning and saw my Fluval 304 canister filter was unplugged.  Without thinking, you guessed it, I plugged it in. Well it only took about 30 seconds for the rotten egg smell of hydrogen sulfide to hit me in the face.  I was crushed as I didn't think of that possibility before as well as I realized there was no turning back once I made that crazy decision to plug it in.  I turned the filter back off and cracked it open and it was very black inside.  I just got back from vacation a few days ago and everything was fine so I don't know how the filter got unplugged. I have a few questions.   First, I threw everything away that was in the Fluval (foam pads, activated C bags, ceramic Biomax, and PolyFilter) and added a fresh 100 g bag of activated C, a whole pad of PolyFilter, and fresh foam pads.  I also started preparing 14 gallons of water to do a 25% water change when I go home.  Is there anything else I can do.  How much C would be reasonable to run; should I add like 6 100 gram packs to the Fluval or just run one?  And the two questions I hate to ask.  Is it almost certain death to my fish since I actually smelled the gas coming out of the water, and will the sandbed and 50 lbs of LR in my tank be garbage now or will the H2S not absorb and contaminate for life? Thanks for the advice as I want to save anyone I can. Ray <Hello Ray, The first and best thing you can do is a large water change obviously, in the range of 50 percent. You didn't mention if this canister filter is the only source of water circulation in your tank, nor did you mention how long it had been off. Those are two rather important pieces of information. Your rock is probably fine, and in all likelihood so is your sand bed, but again I lack some vital information. If your fish are still swimming when you get home, then they'll be fine! For all the talk of hydrogen sulfide gas, I've never seen it whack a fish myself. That doesn't mean it hasn't happened, but in my experience I've never witnessed it. Run as much carbon in your canister as you wish, there is no right answer there. If your sand bed is dead, then all the carbon in the world will not help you, and you'll have to pull it. If you've had power heads or a return pump circulating the water all the while, your sand bed is most certainly just fine. Cheers Jim>

Poison in the water?? Hello Mr. Fenner <Hi there> Thank you for the time that you are giving to solve all our mistakes and problems. <Welcome> I have all your books and I enjoy reading them over and over again and we still do mistakes. <Yes, I as well> I have a 240 Gl FO system. With all the necessary equipment that you recommend I have the system for 3 years know and it was going perfectly. I had fish which were transported from my smaller aquarium to this one and they were doing fine since 3 years. Lately I bought an Aquamedic Denitrator I fixed it according to their specifications and it was OK then after a certain while I realized some deterioration in my system Actually I didn't know why and suddenly fish started dying it was some kind of poisoning very fast fin rot and lashes in the stomach area and fast death. I lost all my fish within couple of days. I thought that it was a disease so I left the tank empty for a month and changed 30 percent of the water thinking that I solved the problem yesterday I bought two damsels to try the system they died the next day quick death. After a month without fish I am still having ( Cyano) the red slimy algae on my rocks I use RO water, the skimmer is not producing much anymore I think that's normal. Other than this I don't know what's going on. <Does sound/read like there is a toxic situation in your system> Yesterday I was reading your book just enjoying it. I realized you mentioned that Denitrator if working wrong they can give Sulfur H poison into the water and this was going on from the day I bought the machine so is it possible that I am poisoning my water all this time and not knowing about it or its another reason. <Does happen.> If this is that case if I stop the Denitrator will my water go back to normal? <Possibly... I would try draining the unit, removing it, trying another couple of damsels> I couldn't find any other reason what do you advice. <You might try adding a "PolyFilter" pad as well... in your water circulation path... and see if this extracts a colored material (a metal)> Thank you Regards Viken <Good luck, life to you Viken. Bob Fenner>

Re: poison in the water?? Possible denitrator issues Hello again I hope you remember my case, All fish died within 24 hours. I changed 30% of the water I tried 2 damsels, again sudden death.  I think I give up. I stopped the denitrator as you told me again changed 30% water, and put one damsel the same case , death in 24 hours. one damsel dying so fast in a 250 gallon aquarium ???? <Mmm, something very toxic> I'm totally confused an aquarium which was running perfectly for 3 years what could have happened. What do you recommend me to do. shall I start all over again. Thank you Viken <If it were me, mine, I would try first just draining all the water out, while gravel-vacuuming the bottom, refill with all-new water, let sit for two weeks... test for nitrogen cycle components... and see if this is enough to remove whatever (biochemical, chemical) there is toxifying the system. Bob Fenner> 

Hydrogen Sulfide - 01/01/2006 Happy new year to you all, <And to you Will.> This weekend I had the pleasure of stripping down my 60(UK) gal marine tank for the 2nd time, what a way to end the year but with a nice slow leak...? Anyway all the rocks corals fish etc. are in a nice spare tank set up with heater, filter, skimmer, and sand is in a vat with water and a powerhead. However my sandbed seems to have been producing hydrogen sulfide instead of nitrogen, kind of lucky the tank leaked in retrospect. The sandbed is about 4 inches deep I should imagine, maybe a little under, I have a bout 240lph of flow through the tank <excluding skimmer>. What's causing the hydrogen sulphide? Bed too shallow? Not enough flow? Wrong bacteria proliferating? <Anaerobiosis, organic build up. Flow must be leaving dead areas.> And other than the smell what effects does this substance have? Suppressed pH or is it actually toxic? <Hmm....Being from lack of oxygen, the pH would be depressed, could have a random "die off" of all livestock.> FWIW soon I shall be upgrading from a Prizm skimmer to a v2skim 400, will this help problems, the Prizm never really does much <other than irritate the family with it's gurgling and bubbling> <Will likely help as will better flow. Good surface turbulence will help gas exchange.> Thank you in advance, Will <You're welcome. - Josh.> Lazy Snails I have a 20gal FOWLR which had a green algae problem. I took out the rock and scrubbed it and did a 25% water change. Now my snails or hermits do not move and they fall off the rock. I know they are alive because they do react when I touch them. What do you think the problem is? Should I pull them? All the water parameters are normal. I also have a problem with keeping a sally light foot crab for more than a couple of months. Shaun Nelson <Hi Shawn, Thanks for writing. Your algae comes from excess nutrient, either as a by product of fish and feeding, or in the source or replacement water. Scrubbing the rock does nothing to resolve this excess nutrient and in fact retards the ability of the rock to help process these wastes. Go to WetWebMedia.com and look up "live rock" and also "algae". You don't mention any water parameters other than to say they are "normal". The nutrient for algae is coming from somewhere. Test for ammonia, nitrite (should be zero for these) Nitrate, phosphates, silicates. Don't forget to test the source water. My guess is the snails, sally lightfoot, etc. are reacting to wastes, likely nitrates. They are also sensitive to salinity changes so make sure you aerate, match SG, heat, buffer, test any new water. The idea is to maintain a stable system low in nutrient for algae. Craig>

Taking Out Toxins, And Adding An Angel Hi Scott, how are you doing, hope you're doing great.!! <All is well! Thanks for the kind words> Well, I wrote you last week to tell you about my tragedy, the good news is that the Miniatus grouper, and the eel, are eating, and see very healthy. <That IS good news!> Now I connected the protein skimmer with the proper house PVC, and it's working wonderfully. <Excellent!> I couldn't believe it when I clean the collector cup. <Those EuroReef's do a great job!> I need some advice. 1st, I all ready changed 2 carbon filters, changed about 25% of the water for 3 consecutive days, and the fish seem very healthy, now I'm sure that the (carburetor hose), is what caused all the trouble, but now how can I now if the toxic (poison) is completely out of the system? Do you recommend putting a few damsels to see how they react, before I purchase another fish, or just wait about a month or more to put new fish again in the tank????? <I would not use live fish for this. Rather, I'd keep up an aggressive water change schedule and use activated carbon and Poly Filter, which excels at removing a wide variety of contaminants from tank water> 2nd. I also got a 90 gal tank at home, and my uncle is in love with the acrylic tank, I was also, but now I feel that the 140gal at the office is too small, so I accepted and am going to sell it to purchase a 300gal acrylic tank. <Cool!> The thing is, at all the aquarium stores the biggest that they have is about 150gal, so I was wondering if you now a place where they sell big acrylic tanks for good prices, maybe a place, or an Internet page so I can contact them???? <Well, your local dealer should be able to order one for you. If not, you could visit Tenecor's web site, or perhaps Advanced Aqua Tanks (Clear For Life)...And there are others. Do a little internet search under "acrylic aquariums" and see what you can find. Believe it or not, these large tanks are still a "standard" size for most manufacturers, but dealers do not usually carry them in stock at any given time.> 3rd. my water parameters at the office are perfect, and the water parameters at home are too, except the Nitrate, was a little bit high, I do 20% weekly water changes, can you recommend something to get the nitrate down, and is it too dangerous for the fish??? Or, maybe do 30% water changes weekly???? <Well, nitrate is not dangerous to fishes, per se, but it can be detrimental to corals. Mostly, nitrate is an indicator of the overall water quality in a system. There are many ways to reduce nitrate, ranging from aggressive water change schedules with quality source water, to utilizing deep sand beds, chemical filtration media, macroalgae cultivation and harvesting in an attached refugia, etc. Check the WWM site for lots of cool ideas!> 4th and last, My wife brought home yesterday a 1" Cortez Angelfish, he looks healthy, but it's very small, about a finger nail. <That IS small, but these fishes can and do grow quite large if they make it to adulthood! Keep this in mind!> She works at a brokers' office and the guy that exports fish gave it to her. <A nice perk at the office!> The only thing I could imagine to do is put it in a 20 gal tank that is well establish and was purpose for hospital tank (just in case), <Quarantine is a great idea for ALL new fishes!> But honestly-if angels are delicate, do you think that this little fellow has a chance, and if he does, what recommendations can you give me. <Well, they are delicate when so small, but if you provide stable environmental conditions, a large aquarium, and quality food, he can grow into a great specimen for a large tank that can live for many years!> Again Scott, thank you for your help, time and advice. Att. Juan Santos. <Always a pleasure, Juan! If you can house this little guy for the long term, you'll have a great fish that will become a part of your family! Enjoy! Regards, Scott F>

Air bubbles I have a 300 gal. marine tank and have live rock and a sand base . I continually have air bubbles , mostly small ones , rise to the surface off the rock and sand. Is this normal or is there something going on in the sand that should be of concern? At one time I had a plenum but have since removed it as I believed it was becoming polluted and noxious gasses were being released from it. Tank is now better but still have these bubbles and am wondering if the sand could have absorbed something from the plenum and is now releasing it into the water. Tank life is generally good but not as great as I think it should be and am looking for reason. Thanks, Jerry Hines >> Interesting... and I agree with you... I'd be concerned to find air bubbles issuing from the sand bed... some sort of biological reactions going on there... and probably not of benefit... What to do? I would begin a regular campaign of gravel vacuuming the bed... a bit each water change/maintenance time... to remove some of the life, some of the food there.  Bubbles from the rock? Could be just exuberant photosynthesis... and I wouldn't worry about this... as free carbonates, other matter become rate-limiting, the bubbling will tone down... BTW, many brightly lit public aquarium reef set-ups have copious rock-bubbling action. Bob Fenner

Re: air bubbles Bob, hate to bother you again, but forgot to add one thing, the bubbles start in the morning when the lights come on and by lights end there are many bubbles being released and still on the rock. In the mornings when I look closely at the tank before the lights come on all the bubbles are gone. I have 10,000k metal halide, 4 of them, and the blue actinic fluorescents, 4 also. they run about 12 hours per day for fluorescents and 10 for the halides. Any advice would be greatly appreciated. Thank you , Jerry <No problems... and my opinions the same... some sort of biological reactions producing the gasses) at both sites... and I would still gently and generally vacuum the substrate, a bit each water change time, and leave the rock alone. Bob Fenner>

Dying fish Hi bob <Anthony Calfo in your service while Bob travels> I am new to saltwater aquariums, but have maintained freshwater tanks when I was younger I bought a 130 gallons tank about 6 months back. Everything was going great until I started to notice algae bloom. I tested the nitrates and found them to be around 100mg-l.I immediately started water changes, lowering them down to around 25 mg-l. the fish seemed to appreciate the lower levels. <agreed.. good move> But when I did the last change next morning my imperator angel got a white film over his body and eyes, was breathing fast and died within 12hours. <incidental toxin in the water or parameter difference (sharply colder or pH difference in new water... should check these and adjust with every water change)> Next was a clownfish then a 7inch blue face angel, all my damsels, a cleaner wrasse, a purple tang, a Picasso trigger a Sailfin tang and a rock beauty dwarf angel. What went wrong? <Wow! Serious chance of a toxin in the water> A friend of mine told me that it was because of my frequent water change witch I did every day when my nitrates where high. He said that it dissolved their protective coating and not to worry about my tank. <with all due respect... this is not even remotely true or possible> He said to wait a couple of weeks and to add a fish to see. I did and it died two days later with a film over his eyes.  <yes... still in the water> I still have a hepatus tang and a large wrasse since the beginning and they are still in top shape. <indeed all fish have varying tolerances and you found two durable ones> All my water parameters where ok (amonia-0 nitrite-0 ph8.0 SG 1.023 temp 77.9F). <pH is way low but not enough to kill. Aim for 8.3 minimum by night and towards 8.6 by day> I was using tap water when I was doing the water changes but let it rest for a day or two and added conditioner.  <no need to rest water... aerating would be nice and buffering> I think I introduced a bacteria of some sort and can't get rid of it. <actual... it is more likely that an aerosol of some sort was sprayed in the room and absorbed in the standing water (air freshener, paint or paint stripping in the house/room... anything with a strong odor is a candidate. Read the cans for a good scare> I'm thinking of disinfecting the whole system and buying a quarantine tank. <The QT is a must. And the main tank needs a very large water change and the addition of some poly filters with the hope that they will extract the contaminant> I still have some live rock is there any sure way of disinfecting it? <may not be necessary with a near 100% water change (adjust temp, pH, salinity and oxygenate)> what do I use to disinfect the tank I have since bought a ro-di unit and will use this from now on. <do read archives on how to reconstitute RO/DI water before any kind of use or you may kill more fish> Do I have to kill my anemone? <huh?> when in the future I buy live rock how do I make sure it's not contaminated? <simply buying cured should be enough or cure it yourself. If you added live rock at the same time as the deadly water change you could have been looking at fouling from fresh live rock> Can I use chlorine to clean the tank any help will be greatly appreciated. big d <the only way you can sterilize is to remove the fish for a month to QT and trash the system. As per above, this may not be necessary. Do the big water change and use poly filters and then try a single test fish a week afterwards. Best regards, Anthony>

Question: I've got a 75 gal tank that's been set up for approximately 2 years. It's a Hexagon shaped Relatively deep tank with the following inhabitants: 2 large Feather Dusters, 1 4' diam. Leather Coral, 1 Banggai Cardinal, 1 blue/Yellow Damsel, 1 Checkered Goby, A cleaner Shrimp, Coral Banded Shrimp and 5 small red-legged Hermit crabs. I've been adding Live rock gradually, up to about 45 pounds now. Filtration consists of a canister type rated at 250 gal/hour, an over-the-side filter, and a protein skimmer that seems to work effectively ( at least I dump green slime out of it weekly). I use a tap water purifier to filter all water that I put in the tank, and test it showing no readable nitrates, nitrites, or ammonia. Water changes are done every month (1/4). I want to build this tank into predominately reef, but I'm having a problem with Nitrates. It's odd because water testing of the tank water reveals minimal ammonia, and absolutely 0 nitrite, but Nitrate stays at 10, and rises. This confuses me because my understanding is that nitrate is created through the decomposition of Nitrite. So I always think that after a water change, with no nitrite evident, the Nitrate will diminish over time. I'm concerned about placing sensitive invertebrates in my tank with my nitrate levels detectable. Please advise on ways that I biologically control these levels. Bob's Answer: Lisa, thx for writing, and esp. with so much useful detailed info. First off, I wouldn't sweat ten ppm of nitrates... not a real peril and to be expected... This resulting concentration is mostly a feature of a typical unbalanced series of ongoing events in a captive system... and you point to the balancing factors that can help you keep this variable in check: 1) More and faster photosynthetic metabolism... A few ways to boost this nitrate-using process. Increase lighting, increase amount of live rock, increase both by adding a (shallower) sump with its own lighting and live rock (ideally on an alternating light/dark cycle with the main/display system), and/or 2) Enhance denitrification. I.e. the reverse process of ammonia to nitrite to nitrates. This anaerobic (largely) series of rxns can be boosted most simply by installing Siporax beads, CellPore material or other small "nooks and crannies" media in the canister filter you mention... but also will be aided by adding more branching coral type live rock, beefing up your substrate (intentionally adding more NNR, plenum area) or really making a Natural Nitrate Reduction system on your tanks bottom... But back to the original statement: don't fret too much re 10 or even 20 ppm of NO3. By itself this is not a worry... and do consider the above approaches. And btw, all nitrate does not come about via nitrite mineralization (or "decomposition", as you list), but that's indeed another lengthy topic.

Question: What do you think about the Electro-Chemical Nitrate Reducers on the market. They advertise that they can quickly reduce nitrates to a "low" level and maintain it there. The idea of eliminating water changes seems "too good to be true". I am interested in using this with a medium-heavy stocked fish aquarium. Bob's Answer: Such devices do work, but at a large cost (relative to what you get) and the whole world of "wastes" chemically, physically and biologically is definitely not limited to nitrates and denitrification. Put another way, no, IMO these tools are a scam and a waste of time for home aquarists. I don't use them and don't endorse their use. <An update... the co. evaporated... RMF>

Dear Bob, My question relates to higher than usual levels of phosphates in my hospital tank. Currently I have no "sick" fish, but in doing my weekly water tests I've discovered the following: Ammonia 0 Nitrite .05 Nitrate 0 Phosphate 3.0 pH 8.2 Alk 4.0 It's been a few weeks since I had any fish in the tank, but I was using CopperSafe. I did not do a copper test tonight, although I've done a few water changes since then. I don't have any fancy equipment on this tank (not even a skimmer). I've used RO/DI water since I started my tank a year ago. I have no substrate, but do have a piece or two of live rock. The tank size is 29 gallons. Will this phosphate level harm my new tankmates I anticipate putting in there soon? What should I do to lower it? My current carbon filter is probably less than 30 days old, but I would anticipate that it has probably pulled most of the copper out? No sign of algae or other problems. My other tanks (29 GA) and (160 GA.) each maintain a phosphate level of .6 generally, never getting to 1.0, but seldom lower. I've tried PhosGuard . .but it didn't really have much affect either. Your help is appreciated. Sincerely, Cavin Lambert <That's a lot of phosphate! There are a few approaches to the high concentration of this major nutrient. One, you can add more live rock, macro-algae... and all the nutrient using metabolism that goes with them... Or, you can use some types of chemical filtrants. My fave is PolyFilter, not to sing that same old song... And the semi last possibility is the constant water changing (let's see 50% would be a 1.5ppm reading...), but where is that phosphate coming from I ask? Do you know? Gotta be from somewhere... food, some part of your decor... where? Find it and limit it. Bob Fenner, who says 0 nitrate? but your other readings look fine.> High Nitrate Problems Bob, I have a 55 gallon reef tank with a 10 gallon sump. I have a protein skimmer in the sump and two power heads in the tank. I have about 60 lbs. of live rock, 5 small fish, many invertebrates, snails and hermit crabs. My problem is Nitrate. Five weeks ago I noticed several snails had died at once so I had the water tested. They tested the water using a TetraTest NO3 and got a reading at about 100. I changed 33 gallons and the figure came down to under 50. However I can't seem to get it down any lower. I get a reading of between 25 and 50. I change about 10 to 14 gallons of water every other week but the level still remains high. These large water changes seem very hard on the tank as well as hard on the pocket book since I have to buy water. I buy RO water from a store because my well water has too many phosphates. I cut back on feeding by half to, a piece the size of a dime of frozen brine shrimp every other day, which they eat in under two minutes. The tank seems fine or at least nothing else has died and my mushrooms look better, but the reading still seems too high. Should I change water more often? Change more of it? Can you tell offer any suggestions. Ken <Hmmm, something is awry here... You don't mention your lighting, but I'd bet it's too little on for too short a period of time. Does any algae look like it's growing on your live rock? I would increase the lighting intensity and duration (you can send me the info. on what you currently have/do.). I'd check that protein skimmer as well. Is it clean? Does it need adjusting? Is it big enough?     The nitrates may be just from parts of the live rock dying off... or...?     Lastly, do look into just getting an RO system for your house. If your tap is not good enough for your system, you don't want to use it for drinking, cooking. These units are not real expensive... and much better than driving and lugging around water. Bob Fenner, who says, next we'll talk about adding some macro-algae to your sump with some live rock and its own light... that'll fix those nitrates and much more.>

Become a Sponsor Features:
Daily FAQs FW Daily FAQs SW Pix of the Day FW Pix of the Day New On WWM
Helpful Links Hobbyist Forum Calendars Admin Index Cover Images
Featured Sponsors: