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FAQs on Marine Water Quality involving Nitrates 4  

Related Articles: Nitrates, NitritesAmmonia, Establishing Cycling, BioFiltrationPhosphate, SilicatesNutrient Control and ExportDeep Sand Beds

Related FAQs: Nitrates 1, Nitrates 2, Nitrates 3, Nitrates 5, Nitrates 6, Nitrates 7, Nitrates 8, Nitrates 9, Nitrates 10, Nitrates 11,  & FAQs on: The Actual Science Re: NO3 Compounds, Importance, Measuring, Sources, Means to reduce: NNR (Natural Nitrate Reduction, Anaerobic Bacteria), Algae, Other Biota, Physical Filters, Chemical Filters... NitritesAmmonia, Phosphate, Silicates, Biological Filtration, Fluidized Beds, Denitrification/Denitrifiers, Bio-Balls, Wet-Dry Filters, R.O./Distilled/Treated WaterChemical FiltrantsDeep Sand Beds

Urchin pic by Jen SaFranko

Information overload...HELP!  11/12/2005 Thank-you for your help in advance. I've been a long time African Cichlid keeper starting out with a 10 gallon tank and working my way up to my existing 150 gallon bow front tank. I took time and patience in learning all I could through reading and the knowledge of others. Then, one fine day the salt water bug bite me. I'd like to convert my 150 gal in the future but right now I am using a 29 gallon starter tank to "get my hands wet" so to speak.  Here is how things look so far: 40 lbs live sand, 40 lbs live rock, Red Sea Prizm protein skimmer that actually works (have read lots of not so good things), 1 rotating power head, Eheim Prof 2 2126 (with only filter pads and Chemi-pure) mostly for water movement and nitrate control and my lighting is 130w=12,000k, 420 actinic blue pc with 4 moonlight for lovely night time viewing.  Specific Gravity 1.024, temp 81 deg, ph 8.4, ammonia 0ppm, nitrite 0ppm, calcium 410(use Kalkwasser drip once a week to replace 1gal of evaporation), GH/kH 8, but nitrate is always at 20ppm. <"It's your filtration"> I do 10 percent water changes weekly as well as rinse/replace filter pads. Stock= 1 yellow tail damsel, 2 blue damsels, lawnmower blenny, sand sifting star, tiger striped star, fancy red star, multiple blue legged crags and a few snails. Not to mention all the beautiful life on the live rock. Now to my question -What am I doing wrong that my nitrates are so high? <Mmm, nothing... due to your filtration mode, maintenance... See WWM re canister filters, maint...> Any advice with my set-up? <Mmm, not on this one, but I would read... maybe a few good marine aquarium books (biblio. on WWM), and our general marine aquarium set-up articles and FAQs files> And with my current set-up would it be possible to have corals and the like? <... some> Worth noting- before using the Eheim I was using a Penguin 350 Bio-wheel filter but opted for more water movement. Thank you for your insight. Frankie <I might put the Biowheel back on and run it at the same time. Bob Fenner> 

Nitrate Problem I have a 72 gallon Salt tank setup for over 18 months now and during that time have had an incredible problem with nitrate levels in the tank.  I am currently using 2 Emperor 400 filters and a Fluval 280 on the tank as well as a red sea skimmer for protein. <Bodda boom bodda bing! I think we may have found the source of the nitrates. Are you replacing the filter material in these canisters regularly? If you're slack with the maintenance of the filtration equipment that you mentioned, you will definitely have nitrates> During the time that we have had the tank we have always had a problem getting nitrates under control: at best we did have the nitrates down to 5ppm but then again the nitrates spiked to over 150ppm. <That is excessive. This could also be a sign of overstocking. Is the stocking rate of the tank realistic?> We have tried everything from water changes every 3-5 weeks to at this point I am running nearly a lb of Denitrate in the various filters.   <I feel pretty sure the problem is the old filter media. Change the media regularly (weekly) but don't remove all the media in all the filters at once. Have a rotating schedule...do water changes weekly, and analyze your stocking level. This should take care of it. Oh...I also see no mention of live rock> This does seem to be helping as now the nitrates are starting to fall but I was curious as to any other suggestions that you may have.  Thank you. <My friend, you are correct. As you seem to realize what good does it do to treat the symptom without finding the cause? Check out wetwebmedia.com for more information. David Dowless>

Dastardly Dascyllus Behavior Steven, You can disregard the question on the clown (Waddles). As of this morning, he is eating and swimming all over the tank. Hope his days of being stress-free are over. <I am glad to hear it.> As for my Domino, so far so good and I'm keeping my fingers crossed. <You can hope, but this fish is going to be a fish. No changing its behavior. Domino's are categorically one of the meanest fish out there.> I know he'll eventually have to go, as I wish to purchase some Cardinalfish in the future. <Agreed> As for my second question, I don't think you answered it. <Perhaps I was not clear enough.> My nitrates (been at this same level for 2-1/2 weeks or so) seem to be "stuck" at 25 mg/L (according to the test) and the guy at the LFS suggested I make a 20% water change since in his opinion, the tank seems to be "stuck" at the end of it's cycle. <You LFS guy is incorrect about the cycle. You said you tank is run with an undergravel filter. If so, you will always have nitrates. You do not have a sand bed and are therefore unable to culture denitrifying bacteria. You will always have nitrates that you will have to continually try to dilute with water changes.> Been up and running for 6 weeks, ammonia zero, salinity is normal. What is your advice on this? Should I make a water change? <Yes, but do not think that eventually you will not have a need for them. Even with a DSB and complete denitrification there is always a need for water changes.> Thanks, Maureen <You are welcome. If I was not clear enough or you need further explanation, feel free to email again. -Steven Pro>

Unhappy new addition?? Hi there again, guys! I have a zillion more questions for you, but I'll limit this session to just two. I have a 20 gallon saltwater, UGF, etc. I purchased a tank raised Percula clown yesterday, acclimated him, and he seemed okay. My yellow-tail blue damsel started attacking him and wouldn't leave him alone. He even tried to bite! He was smacking him in his face with it's tail and had him cornered and wouldn't let up. <This is not unusual behavior for damsels. They are inherently territorial and aggressive.> Needless to say that the damsel is now gone, but the clown (Waddles) is still hiding and won't eat. I had to really move around some rock to get that little @#*&@ out. Is he still unbelievable stressed or should he have a companion (there were 4 in his tank at the LFS)? <I would bet on stress, damage, even just plain old fear.> My Domino damsel doesn't bother him. <No yet!> Any suggestions? <I always try to plan out every fish I put in a tank before I put any in. Come up with a game plan and you will have fewer problems like this in the future.> Now on to question number 2. My tank has been up and running for over 6 weeks and my nitrates are still hovering around 25 ppm (according to how the test reads). The guy at the LFS suggested that I do a 20% water change since in his opinion it seems my tank is "stuck" (ammonia zero, salinity is normal). The nitrates have been at this level for about 2-1/2 weeks, maybe a little longer. Any suggestions on that as well? <I am a bit confused. You will always have nitrates with an undergravel filter. You do not have a Deep Sand Bed to perform denitrification. Perhaps you should invest in Mike Paletta's "The New Marine Aquarium." It is an excellent first book. Very easy to read and pretty short, too.> Thanks again, Maureen <You are welcome. -Steven Pro>

Hardy Inverts Hi. My tank has a nitrate level of 25 ppm. Which invertebrates are rather nitrate tolerant? <Mushroom anemones would be ok.> I would like to add algae grazers and scavengers but have good growths of Caulerpa and Halimeda as well as coralline red so I would rather not have too much eaten. Which herbivores could now be added to control other algae but which would leave most of these introduced species alone? <Various algae eating snails would leave the macroalgae and coralline alone. -Steven Pro>

Nitrates and help with Mad-Clown Can't believe how much I have learnt since I have found your web-site. I thought I had eased myself in to the hobby with reading about it for 6 months / hovering around LFS's etc.. before laying out my cash. Disappointingly, I have found that my LFS's give conflicting advice and with retrospect am dubious of the set-up I have been sold. However, to date (the tank has been set-up for 8 months) I have a 55g tank with approx 60Ib's of live rock and some soft corals. All readings are ok with the only concern being a nitrate fluctuation that creeps up to 10ppm (normally about 5ppm). For filtration I have 1 internal filter (PolyFilter & carbon), 1 external Fluval 404 with half the chambers containing biological media, a quarter containing the Kent Nitrate reducing product and the last chamber containing filter floss. My question is, is the bio-media in the Fluval doing any good? It always looks so clean, should I replace this with something else (bearing in mind the live rock)? <I would chuck the biomedia altogether and use nothing but carbon, changed regularly. I suspect your biomedia is the source of your nitrates. Increase LR and live sand to naturally reduce nitrates.> I use a Prizm skimmer which I find works quite well (dark gunk coming out!). Additional water movement is made by 2 internal mini-jets. Turnover should be ten to twenty times tank volume. IOW, for a 55, 550 GPH (minimum) total for all the powerheads.> I have some soft corals in the tank that have grown and look incredibly healthy and to date the only casualty has been a snail, which just seemed to have disappeared! The fish in the tank are: - 2 Ocellaris Clown (1in and 1.5in) - 1 Bi-Colour Angel (3 inches) - 1 Orange Stripe Prawn Goby (2 inches) - 1 Yellow Tang (4 inches) Besides the questions concerning the filtration above, I would really appreciate your help with the below: - Do I need to supplement the oxygen from the skimmer with an additional air stone? <No. If it's cleaning dark skimmate it's fine.> - The yellow tang is a new addition and has just come out of quarantine. He has been in the tank now for 48hrs. However, the larger clown has taken a strong dis-like to it and it tormenting it non -stop. The poor tang (a giant beside the clown) is cowering under a rock and will not feed (feeding fine in quarantine) <Re-arrange the clowns digs some to throw him/her off and add some well cycled live rock. This will change territories and add to your nitrate reduction capacity while removing the biomedia from the Fluval, etc.> - Any additional advice on keeping the nitrates down. <Less nitrifying outside biomedia and more natural de-nitrifying LR and LS.  Regular cleaning of sponges, any other filters.> I have a Aquamedic R/O unit at home and do regular 15% water changes every week. The sand base is just under an inch and is vacuumed / disturbed once a week using a Eheim device which doesn't suck in sand. Look forward to your responses. Bill <Ah....stop this, add more LS, (slowly over days), get some  detritivores to keep your sand in shape....stop vacuuming, it disrupts the natural sand processes, even in thin sand beds. Your thin sand bed could also be nitrate source, especially with disruption. Should be fine with enough rock or by adding more LS. Hope this helps!  Craig>  

Rubbermaid got nitrate Looking to set up a Rubbermaid 150 gal sump out of one of there stock tanks. Question is, do you know if Rubbermaid has nitrate in the plastic? Have heard that this might be a problem for a reef tank.  Thanks. <Mmm, made of Polyethylene... carbon, hydrogen, oxygen... no nitrogen... no nitrate. No problem. Bob Fenner>

Nitrate Nightmare Hi WWM Crew! <Scott F. here today!> I have a 55g FOWLR, 120g FOWLR and a 20g tank that is currently without fish but running. I have had constant problems with  high nitrates in all three of my tanks.  I recently changed from buying  water from my LFS to mixing and storing my own salt water. I store and  mix the water in a 30g trash can with 2 powerheads constantly running. I haven't yet, but I also intend to add a heater.  So far I have only been using the container for makeup water, so on my first run of using it for a water change, I mixed the salt and Amquel and let the water aerate for 2 days before doing a water change.  Immediately after doing a 20g water change to my 120g tank, I did a water test that indicated the nitrates were high in the tank. <May be in part because of high nitrate present in source water, but also possibly due to husbandry. Do re-visit your maintenance procedures, feeding, skimming, etc., to make sure that these factors are not contributing to the problem. Fortunately, these are easy to correct!> I have the Saltwater Master Liquid Test Kit that uses a color chart for readings, so it's very hard to tell exact numbers, but let's just say it read that the nitrates were fairly high. Anyway, after realizing that the nitrates were high in the tank, I tested the stored water.  I realize that I should've tested it before doing the water change, but I'm learning as I go.  : ) <Hey- at least you're testing! That's great. Don't be so hard on yourself!> I found that the pH level was low, so next time I will buffer the water to bring it to 8.2. <Good procedure> I also  found that the nitrites were high <Bingo!> ....this is where my query comes in.  My thinking on the issue is that by using Amquel to get rid of chlorine and ammonia, the ammonia is converting to nitrite during storage and then to nitrate in the tank.  Does this sound logical? <A very interesting theory, but I'm inclined to believe that the fresh water was high in nitrate to begin with, and certainly not helping the existing nitrate situation in your tanks. When you're starting out with source water that's, say, 5ppm or more nitrate, you're "behind the eight ball" already!> If so, what can I do to remedy the problem? If this explanation doesn't sound right, what do you suggest? <I'd recommend that you invest in a good RO/DI unit that can produce virtually pure water at a modest cost. This way, at least you can be assured that you're starting with good source water> Seeing that I have 3 tanks, it got to be quite cumbersome getting saltwater from the store, so I really want to learn to mix my own water. <Agreed- been there- done that!> Does this sound like a problem that a chemical tap water purifier could fix or is an RO/DI unit in order, or is there something else that I'm missing? <Nope- as above- an RO/DI should help. But do investigate husbandry, maintenance, etc. to help reduce nitrate levels in your tanks.> Thanks in advance for your help.  You guys are the coolest! <Not as cool as our readers! Keep up your efforts at learning and improving your systems! You're doing great! Regards, Scott F.>

Re: E. quadricolor Hello All, Thanks for the good advice in the past! <You are welcome.> I bought a green tipped bubble anemone yesterday and put him in my FOWLR tank (50 gallon). My nitrates tested around 20. Too high? <Closer to zero would be better.> What do I need to watch for in the animal to see if it is affecting him? <Once you see symptoms, it will be too late.> I plan to do water changes to get this level down. <This will help if your new water is free of nitrates (RO or DI water with a good salt mix).> Would a refugium setup be a good idea here to keep it very low in nitrates? <Yes, another part of the equation along with the water changes, other nutrient export processes, proper feeding, and all other aspects of good husbandry.> My lighting is 2 55-watt Custom Sea Life Smartlamps. The tank is only 16" deep and the tallest live rock is 10" from the bottom. Is the lighting adequate? <It does not sound like it. I would ballpark this as about half to three quarters of needed light.> I plan to feed him Formula One and Mysis a few times a week. Let me know if there is anything else I need to know. I have read through the website and some of the FAQ regarding this animal. Thanks again for your services. Michael <You are welcome. -Steven Pro>

Re: Tonga rock - Nitrate control Anthony: Thank you for your quick and informative reply. <my pleasure> A couple of minor questions and points before I move on. I want to make sure having a deep sand bed will be ok with a heavy fish load. <indeed... not always so. It requires very strong water movement and dedication to aggressive nutrient export. This means have one or two wicked quality skimmers (no red sea, SeaClone, prism, Kent stuff here :) ) that actually produce daily skimmate with ease and consistency> If so, I will add more sand to give me the 4" depth and remove the coral rock I have in there now. Additionally, I will use the Tonga branch for mostly decorative purposes and also to create various "ins and outs" for the fish to feel secure. <agreed... cool> I think the Tonga will also help increase the effectiveness of the sand bed because I can place it in away that will leave most of the sand be exposed (greater surface area) rather than using rock which will cover a lot of the sand bed. <very good point. Agreed> My final thoughts are: 1) Use deep sand bed to help with water quality, nitrate reduction, etc <easily achieved> 2) Eliminate large coral rocks to increase actual gallons of water in the tank from reduced displacement. I can probably gain about 20 more gallons back. <a minor concern or help > 3) Use Tonga branches to break viewing lines, create caves and hiding places etc to reduce any stress on the fish. What do you think? Gene <very cool>  PS. I have used your web site many times to research various topics and have submitted a couple of questions. It's a true pleasure to have you guys to turn to! <its a labor of love... and thank you, my friend. Anthony>

Nitrate Reduction Am currently changing about 25% of water monthly and have a Euro reef skimmer as well as drip biological filter for my 100 gallon fish only tank but am running Nitrate at over 40 ppm. Should I change water more frequently or use a chemical solution to lower them. If either, what do you recommend, please? Thank You, Stephen Pace <Well, Stephen, there are a few things that can be done to help lower the nitrate level in the tank. First, you can increase the frequency of your water changes (try smaller water changes a couple of times per week- like 5% each). Your skimmer is a very good one, and is capable of pulling out a lot of dissolved organics from your water. Is it producing a few cups of dark skimmate each week? If not, please adjust it until it does. Also, be sure to clean the skimmer a couple of times per week. It can be a bit of a task, I know- but you'll achieve much better results with a clean skimmer. Another thing that you may want to consider (do read about this in the wetwebmedia FAQs first) is to discontinue the use of any plastic biomedia in your filter (bioballs, etc), and utilize the live rock in your system for a natural filter (assuming that you do have a sufficient quantity of rock in the system), along with a deep sand bed (3 inches or greater of fine sand). These steps, if executed properly, can lead to a big reduction in nitrate. Thanks for stopping by-let us know if we can be of any further assistance! Scott F.>

Tonga rock - Nitrate control To the always helpful crew at WWM: <Howdy.. and thanks kindly> I currently have a heavily stocked (Craig has already reminded me of this)110 gal fish only tank that I am in the process of removing the crushed coral substrate <a good move> and will be replacing it with Carib-Sea's Arag- Live Special Grade Sand and Carib- Sea's Bermuda Pink Sand (3bags Arag-Alive 1 bag Bermuda Pink). <save your money on so-called "live" products unless you like it purely for aesthetics. A less expensive, more attractive sand (if another suits you) can become more live from a single inoculation of real live sand from a reef tank/LFS in 2 weeks. The whole "live" sand in a packed bag is quite shameless marketing IMO. Technically, any product not sterilized and hermetically sealed is "live" with bacteria. Ha! What a crock> I think this should give me a depth of  about 1 1/2".... for now. <whoa! You will want thicker or thinner but not in between 1/2" and 3". Not deep enough for nitrate reduction, but too deep for nitrification. Likely to become a nutrient sink instead> (maybe I should have a deeper bed?) <OH Ya! Nitrate reduction begins around 3" but aragonite has a half life of around 18 months... so a 3" bed begins to dissolve and weaken from go... hence, start with at least 4-5 inches and enjoy a fine natural nitrate reducing vehicle> Now for my question...I was also thinking of removing the coral rock (not live) that has been in the tank for 3 years. I am not sure how many pounds it is but it displaces about 25 gallons of water...some  large and heavy pieces. I was thinking of going to Tonga branches. I was wondering if the Tonga branches can/will perform the same function as Fiji rock. <not even close. Branch rock is attractive to me, but the fact is that it is not porous Fiji rock but simply dense and encrusted Acroporid skeletons (corallums). Really weak for a biological filter but quite attractive, again, and adequate for very light bio-loads> My local store currently has both fully cured.  I primarily used the coral rock to make various caves etc in order for the fish to feel secure. I'm thinking the Tonga will give me same effect with a lot less water displacement, <agreed> and get the benefits of having some live rock in the tank to assist in nitrate reduction. <live rock of any kind is weak for nitrate reduction... you need huge rocks for that to occur. Deep live sand is much more effective at nitrate reduction> Will the change over really help with my  water quality or should I consider saving the additional expense and just keep what I have? <if deep sand and/or porous live rock are not options then stay where you are with the mature stable substrate that you have> Your thoughts are greatly appreciated. Thanks, Gene <best regards, Anthony>

Reducing Nitrates (Pt. 2) Scott, Thanks for the tips! I had not thought about the sump increasing the water volume.  <An often overlooked benefit of sumps!> I will add to the sand base since it is only about 1.5 - 2 ". Any recommendations on good in sump skimmers?  <Well- since you have an Aqua C already, why not try one of their in-sump models? Good stuff!> Have been thinking about an RO unit as well since I have been buying RO DI water from the local grocery store. No more fish. <g> We would just like to add some more polyps or Xenia once the nitrates are under control. <Yep- that should be okay> Thanks again! <You're welcome. I'm really glad I could help! Let us know if we can be of further assistance! Good Luck! Scott F.> -Bryan

Nitrate Rising Hello! <Good evening! Scott F. with you!> I enjoy your web site and love the Q&As. My wife and I started a reef tank almost a year ago and all is mostly well. The one problem we have been fighting is high nitrates. Readings jump to 40 - 60 ppm just a few days after a water change. I have removed the canister filter we were using since I was worried that it could be acting as a nitrate factory even though I clean it every 7 to 10 days. I feed the fish a very small amount of food once each day. I have read much about nitrates on this site as well as others and in some very good books, but I am still stumped. The tank setup is a 37 gal, 70lbs of live rock, live sand, 2 Ocellaris Clowns, Coral Beauty, Six line Wrasse, Yellow-tail Blue Damsel, Neon Goby, various mushrooms, Brain Coral, Star plops, 2 Bubble Tip Anemones, 2 serpent stars, snails, and crabs. We also use an Aqua-C hang on protein skimmer. I am thinking on adding a sump just to get the heater and powerhead out of the tank for a cleaner look and will be moving to an in sump skimmer. Any suggestions? Is the bio load in the tank to high? Thanks for your insight. -Bryan <Ok, Bryan, lets touch on a few things that could make a difference. First, your tank is, as you may have suspected, at about the upper end of its fish capacity. You seem to be a careful feeder, and that's good. Don't add any more fish! Your idea of adding a sump is a good one, as it will not only give you space for a bigger skimmer, but it will add to your system's total water volume. As Anthony likes to say, "Dilution is the solution to pollution"! Speaking of dilution- how often do you perform water changes? Try smaller (5% or so) changes twice weekly. Siphon as much detritus as you can. And, check your source water. If your starting with tap water that has 10+ppm nitrate, that's a contributing factor, too. Maybe time to look into an RO unit? Your skimmer is one of the best hang-on units around, but make sure that it's pulling a cup of that yucky stuff out at least a few times a week-and clean the skimmer often, as the drying organic product will impede waste collection (sort of a vicious cycle, huh?). Do consider a deeper sand bed (3 inches plus), as natural denitrification is more effective in a deeper sand bed. Finally, consider growing some macroalgae in a lighted portion of your sump (when you get one), and harvest it regularly and religiously. Avoid Caulerpa- try macroalgae like Chaetomorpha or even Halimeda. These algae do utilize excess nutrients (nitrate among them), and can have noticeable impact on nitrate when maintained in suitable quantities and harvested. Well- I hope I gave you a few avenues to explore to help resolve your nitrate problems. Make use of the great resources we have on the wetwebmedia.com site. I know you'll be successful! Good luck!>

Location of articles specifically explaining benefit of removing biomedia from wet dry filter Hello and thank you for reading this.  <Hi Richard> I have gone through most of your articles regarding the benefits of removing the bio media in a wet dry filter. My question is what specifically is the benefit of removing the bio media from the wet dry trickle filter.  <These bio-media convert nitrite to nitrate as a dead-end process awaiting your export via water change. Removing them and relying instead on 1 -1.5 lbs of live rock per gallon and deep sand beds further breaks the nitrate down to it's gaseous form in the deep anoxic recesses in the rock and sand and it rises to the surface of the water. This does not preclude removing other non-nitrogenous wastes and replacing vital elements with regular water changes.>  I understand from your articles that the live rock and live sand will do the job of the plates or bio balls or whatever was in the wet dry. But specifically what is the benefit. For example does live rock and live sand take the denitrification a step further, for example convert nitrates into some other substance? <Yes, gaseous form, as above> Does relying on the live rock and live sand remove the need for water changes?  <No.> I currently am using a wet dry trickle filter as well as live rock and live sand in a 90 gallon tank. The inhabitants include three damsels two perculas about 30- 40 pounds of mixed live rock and 3-4 inches of live aragonite sand. Things are going fine everything is thriving as long as I change around 20 gallons of water a month. Will removing the bio media in my wet dry trickle filter improve my water quality to the degree that water changes are no longer needed or are needed less frequently? If you would kindly point me in the right direction I would greatly appreciate the insight. Thanks. Richard Slocum <I would advise adding more LR before removing the wet/dry although you have a relatively light bio-load. There is much more on live rock and sand on WetWebMedia.com. Scroll to the bottom of the page and type "live rock" into the google search engine. Craig> 

Source of Nitrates Hi. I was wondering if my elevation in nitrates (200 ppm) can be the result of my 200 watt UV sterilizer on my 55 gallon aquarium? <Nope> Is the UV light killing off all the good bacteria to get rid of the nitrates? <No, UV's only kill what is passed through them. Denitrifying bacteria only occur in low oxygen environments; deep sand beds and deep inside porous live rock. They would never be free floating and going through the UV. Nitrates accumulate from overfeeding, overstocking, poor nutrient export, not large enough or frequent enough water changes, from low grade salt mixes, from source water, etc. Please examine these possibilities and take corrective measures.> Thanks, JPK <You are welcome. -Steven Pro>

Nitrates I wrote before and was not specific enough in my email. Sorry. <No problem Abby, let's see if we can get it right this time!> I have a 110 gallon tank that is 10-months old. I have a flame angel, blue tang, 2 damsels, 2 neon gobies, 2 sally light foot crabs, 2 cleaning shrimp, 8 turbo snail and 100 pounds of live rock. I also have an open brain coral, a colony coral, and a finger leather coral. I started the tank using the Tidepool Biowheel by Marineland. I did do readings ahead of time and knew a little about wet/dry trickles becoming nitrate factories but it was the best option for me at the time. I have read that you have suggested to others to remove a little biomedia at a time. This will not work in this case because all the media is contained together in a wheel. Right now, nitrates are at 10 ppm with ammonia and nitrites at 0. I was wondering what I could do to avoid the onset of serious nitrate problems. I change 20-30% of the water weekly, utilize a Fluval 404 and Berlin protein skimmer as well. Is there any media I can replace the wheel with and then remove that slowly or should I remove the wheel completely. thanks for your help. Abby Kengersky <Alright, you want to wean your system from the Biowheel and fully loaded Fluval. The amount of rock you have should be able to handle the bioload you have. Not too many fish at all for 110 (congratulations!). If you feed lightly it will help make the transition easier but your LR should be able to handle the fish you list. I would also think about the Fluval being a similar problem. Most folks I know use them for carbon periodically and run them empty the rest of the time. It sounds like it is just the nitrates produced by the filters that are the problem so make the switch, test and be ready to change your water (sounds like you already do). You might consider adding more well cured rock or a deep sand bed to help with the nitrates. If you are worried about a fallback position, keep the Biowheel filter running in some heated change out water just in case you need it. Not to worry, my bet is the Biowheel and Fluval produce the nitrates. Just give the rock (your real biofilter) time to adapt if needed. Make sure your circulation is adequate. (Up to 10X volume for reefs). Craig>

Does eliminating bio balls help eliminate nitrate Dear Bob, <Gage here this evening.> I had the opportunity pleasure to meet you many years ago, (about 5 years) back in Monroeville PA. This is where I lived and worked in the trade for about 5 years before returning to my native home of California. I moved from Pittsburgh to Rancho Santa (South Orange County) back in 99 where I still live today. I have a question with regards to the true "Berlin" system. If I am correct, the true Berlin system is a bare bottom tank with good circulation, live rock, sump and a good proteins skimmer and micron prefilters. The main goal is to eliminate the need for any outside biological filtering media such as bio balls, with the purpose of eliminating a breading ground for Nitrosomonas and Nitrobacter bacteria, which then eliminates the nitrogen cycle and it's final waste product of Nitrate. Does this make since......if not bare with me. Nitrobacter bacteria grow on any and all surface areas that are provided with oxygenated water, and they only colonies in amounts that are needed based on the waist load. So, if you have a sump with bio balls, how could this contribute to the nitrate problem; If the bio balls are available, the bacteria will colonies on them, and it will also grow on other surface areas in the aquarium (liverock, glass walls, etc). If the bio balls are removed, since the Nitrobacter bacteria only grows to the amount needed, the same amount of bacteria would then just colonies in other areas of the aquarium system, still producing the same amount of nitrate, which is then removed by skimming and water changes. So my question is: Does eliminating bio balls really help reduce nitrate? <Sort of. If you remove the bio balls you will need to replace them with something else, like more live rock. Pound for pound the live rock is much better at filtering your water and removing nitrates.> or am I completely wrong in my theory because the skimmer is suppose to remove all waste before the nitrogen cycle has a chance to happen? <The nitrogen cycle is going to happen no matter what. Using live rock in your filter instead of bio balls will ensure that you are better equipped to handle the nitrogen cycle. Check out the link below for some good info http://wetwebmedia.com/nitratesmar.htm> Thanks for your time with regards to this matter. Sincerely, Mike Proctor P.S. Tell Anthony I said hello...he might remember me as "The Fish Guy", my aquarium service in Monroeville. <will be sure to, best regards, Gage>

Toxic Water (Nitrates) Hi, I am having a problem with my tank. Last month my nitrates were 200 and my nitrites were 10. <Ugh!> I don't understand how because I did a 20% water change monthly. <Well, lets work this through. Let us assume your tank produces 1 ppm nitrate per month. Now, you do a water change of 20% each month and lets also assume (which is not always true) that the new water you use has zero nitrates. The 1 ppm you had at the end of the first month is now (after the water change) 0.8 ppm. Now after the second month, you have 1.8 ppm nitrates, which you do a water change and bring it down to 1.44 ppm. Month three, it increased to 2.44 and was brought down to 1.95 ppm. Do you get the progression? Nitrates accumulate and need to be monitored monthly, so you can later your husbandry.> My tank is 55 gallons and my filtration includes a wet-dry good up to 150 gallons and a Prizm skimmer good up to 75 gallons. <Your Prizm needs to be accumulating a cup of dark skimmate everyday.> I also have a UV sterilizer 200 watt. I did a 50% water change and that didn't not bring the levels down. <It should have cut the levels in half. Perhaps your test kit is inaccurate or not sensitive enough to distinguish between 100 and 200 ppm. Both are too high. The other possibility is to check your new saltwater. It may not be free from nitrates, either from the raw water you are using or from your salt mix.> I put a nitrate sponge in my sump as well as activated carbon. <IME, these have little to no impact.> I also put a Polyfilter in my drip pan. I cut back on feeding to once every other day too. The levels after one week were nitrates 200 and nitrites 0.5 ppm. <Well, at least the nitrites have gone down.> I noticed my dogface puffer has been getting ich off and on for the past month since these levels were elevated, tonight he is covered with it. My levels from yesterday were salinity 1.021, temp 80, nitrates 200, nitrites 0.5 ppm. What can I do to get them down? <A series of 50% water changes using nitrate free water.> I did a 10% water change yesterday. <This will do next to nothing.> Should I do these daily or weekly? <I would perform a 50% water change every other day until your nitrates have dropped to 20 ppm.> What percentage should I be doing? <See above> Please help. Thank you. JPK <Good luck! -Steven Pro>

Plants for nitrate reduction Hello to whomever may be answering questions tonight! I just have a couple of simple questions. I'm trying to reduce nitrates. I've been reading the faq's on your site, and noticed that plants have the ability to lower nitrate levels. Could you please recommend a few?  <Mmm, Halimeda, Caulerpa species grow best/fastest for the purpose in hobbyist systems> Would these plants take over my tank or make burrowing difficult for my sting-ray?  <Yes> If so, I'll just put them in the sump, but I was thinking that the tangs might like to graze upon whatever plants were introduced to their home. Thanks for your help, you guys rule (: Ro <These are actually not plants, but algae/thallophytes... you can look up true/vascular plants, use them... or both in a sump/refugium... a good step for many purposes. Bob Fenner>

Excess nitrate Dear Bob: Before I begin I would like to say a I am an avid visitor to your website. I am forever researching all kinds of topics...also I have read your book many times and have used it as a reference on many occasions. Additionally, looking forward to seeing you at the Brooklyn Aquarium Society.  <Thank You Gene, I know Bob really appreciates your support and input!> Now for my question: My question is regarding a 110 gal fish only tank. About a year ago my nitrates were about 20ppm (fastest kit). Over the last two months my nitrates are now at 40ppm and I have an idea i would like to do to reduce them but I am not sure if it will really work. Right now i have approx 1/2" of crushed coral and shell substrate...just enough to cover the bottom of the tank. I was thinking of removing that and add approx 1 1/2" of live sand. Paul Hunt of "Practical fishkeeping" is setting up a fish only tank and is using 1 1/2 " of sand to help with reducing nitrates (this is where I got the idea from). Some additional stats before I move on: 110 gal tank 48"x18"x30" Lifeguard fluidized bed filter 2 Aquaclear 500's (contains Cellpore & Chemipure) CPR Bak Pak Skimmer 15w Aquanetics UV 3 regular fluorescent bulbs 120w total approx 11 hrs per day 12 gal water change each week Ph 8.0, ammonia 0, nitrite 0, nitrate 40ppm (i don't check any thing else), sal 1.019 temp 80 Livestock: Volitans lionfish Yellow tang Passer angelfish Cuban hogfish Crosshatch triggerfish Vlamingi tang Snowflake moray Regal (hippo) tang Cleaner wrasse one large hermit crab The above fish have been in the tank ranging between 7mos and 3 yrs. (I know your are going to say i am over stocked and you're probably right)  <Most assuredly so.> I think the Vlamingi tang, which I have had for almost 2 yrs, will be donated to a public aquarium here on Long Island where they currently have a reef tank that contains about 4 Vlamingi's already. I have thought about a plenum set up, which I have in my reef tank for the last three yrs and is doing well, but I think my stocking is too much for a plenum set up.  According to Bob Goemans he does not recommend a deep sand bed directly on the tank bottom, another reason I was thinking about only going with a sand bed of 1 1/2". I trust his judgment and research in that regard (he has also complimented you in his writings) Also, adding live rock would also be a possibility but a lot more expensive than just adding the sand. Back to my original question, I can easily siphon out the substrate I have and add the sand Nature's Ocean was what I was going to use) but will it really help? <Absolutely. The 1.5" of sugar fine sand (Natures Ocean) is in essence a de-nitrifying deep sand bed, just one of degree. Note: Nature's Ocean recommends 1 lb per gallon to accomplish this. There is no reason I can see other than overall tank depth and personal taste that a deeper sand bed wouldn't be your choice although a good degree of denitrification will be available with 1.5" of fine sand, perhaps more with your fish load. The live rock would definitely help with this process, seed the sand with additional bacteria, and provide some natural grazing for some of your fish. PLEASE make sure any rock is well cured and smells like good clean, healthy, ocean. The nitrate is likely from your crushed coral bed and very small skimmer for this load and size tank. Please consider upgrading your skimmer to something designed for your size tank and of high efficiency. (Aqua-C or Euro-Reef are favorites, check out our WetWebMedia sponsors). The CPR is maxed out at about 70 gallons. With this number of fish it's overloaded.> Also right now I use a gravel vac during my water changes but with the sand how should that be maintained. <Detritivores, snails, hermits, etc. Be mindful of fish predation on some types of detritivores (shrimp and crabs) and stock accordingly. Disturbing a sand bed interferes with the bacteria, pods, life forms that do the dirty work, it is not usually necessary to vacuum. A small powerhead works to periodically "stir" detritus into the water column where it can be filtered out. Please pay special attention to your filters and clean the sponges/media regularly (in used tank water) to avoid nitrate build-up. The sand and clean-up crew do most of your work on the substrate.>  Your thoughts are greatly appreciated. Thanks for your most valuable time, Gene Lotardo PS. Maybe 40ppm nitrates is not so bad..... <Nah, you don't want that! The alternative is too easy to achieve! I would go for it. DO watch your water quality after switching or switch partial amounts over a week or so. If your amm/nitrites peak, perform water changes until the sand catches up. Usually not a problem, maybe a small amt. of ammonia with this new sand. Test, test, test, and change if needed. Good luck! Craig>

Nitrate production I have a saltwater tank that is 10 months old. Everything is fine except I am worried about the nitrate levels getting out of hand in the future. I use a Fluval 404, Tide Pool 2 wet dry filter with overflow box and Berlin protein skimmer. I did read before hand about the problems with wet/dry filters but really it was the best option for me at the time to use to start up the tank. I know that you have recommended to others with wet/dry filters to just remove a little bit of the biomedia at a time until it is all gone. The Tidepool has a wheel so all the media would have to go at once or all stay. Nitrates are at about 10ppm now and all other levels are within normal limits. I am just worried that the nitrates will climb. I have a 110 galloon tank and change about 20-30 galloons every week. Will I face a nitrate problem and how should I adjust the Tidepool and biomedia to prevent this problem. Thank you for your help. Abby <You don't mention what you keep in this aquarium. Sounds like fish only, so no worries! Just stay on top of the water changes. If it's a reef tank then you may need to address this soon. In either case you can't remove biocapacity (filter media) without replacing it with another or you will overload your tank. Removing biomedia usually involves adding a nitrate reducing media like Live rock and deep sand beds first. These need to be cycled and well established before removing anything from the wet/dry or the Biowheel. Hope this covers it! Craig>

Nitrate Crisis (Part 2) WWM Crew: <Scott F. with you again> (Kelly here, Daniel sent you guys the first note; I am the "significant other" worrying profusely *grin*.) Thank you so much (everyone) for how quickly you are able to answer our e-mails, and how dedicated to education you all are. I need to make some clarifications, and your response has sparked a few different questions. I think the best way will be to cut in on the existing dialog with my own input and shoot for some clarity to this "muddy" situation! He works nights, so communication is not always optimal.... Sorry for the length, by the way. >*He has removed the DLS at my insistence, prior to the water changes today, Chemipure and poly filter and carbon are all in place as well.* <Good!> *The nitrates at this go round (finding my beloved Sailfin) were nearing 40ppm, and we did not test again after the second 6 gallon water change until last night (see below)...I'm afraid he was mistaken about the 100ppm, it was very high, but in truth the test from last night was between 60 and 80, he read the test more than an hour after I took the sample and tested it which was last night....there is more on this below, it's very hard to clarify. Daniel may have been trying to condense our experience for the sake of your time which we both greatly appreciate.* <That's what I'm here for, it's okay> *Do you think we might find a balance in raising the sandbed to 4 inches in both the tank and the refugium, keeping the bioballs in the filter? Daniel also suggested partitioning the sump to add a nice deep sandbed there as well. The reason for this question is oxygen, as the tanks day to day temperature here in Houston in the summer is determined by how much A/C we can afford! He has essentially built the entire system: wet/dry, skimmer, refugium, sump, and hood (awaiting better lighting), and I'm sure he can modify it to your suggestions.* <I think that increasing the sand depth and retaining the bioballs would be kind of counter-productive, sort of a "tug-of-war" with no winner> >Make sure your skimmer is adjusted to produce at least a cup of  >dark, yucky stuff weekly. And finally, if you really want to use  >Caulerpa in your sump, *I'm sorry to be a pain, but I've read through some of the Caulerpa FAQ's and found nothing on how to actually "harvest" it. Essentially harvesting the Caulerpa would be in fact "ripping the fronds" no? I thought it was the runner that you are to keep from damaging. Maybe I missed something...? We are both confused by your reply.* <Sorry for the confusion! It's almost impossible not to rip some of the fronds when harvesting Caulerpa, but you can gently pull lengths of it out in clumps. You just don't want to radically rip it out, because there are numerous toxic compounds that can be released into the water which are not too good for the life in your tank. In the long run, I'd eliminate Caulerpa. just ask Anthony- he loves to tell people that "Friends don't let friends by Caulerpa!" >do harvest it regularly-a good source of nutrient export. Be careful not to rip the fronds while doing this. Keep reading on the wetwebmedia site for more information on maintenance.> *Thank you again for all your time and effort, the website itself is such a plethora of information that I'm sure I miss some things every time I'm there! I hope I was able to clarify our situation for you. Take care :) Kelly (and Daniel) in Houston <Glad I could help-let us know if you have any more questions- Regards, Scott F.>

Nitrate Reduction Dear WWM crew, <Scott F. with you today> First off, I'd like to put out my thanks for all of your time and effort spent helping fellow hobbyists. Now, for the crisis. I have a 29 gallon FOWLR tank with a 5 gallon refugium containing Caulerpa prolifera and a nice large number of visible pods, a 10 gallon sump with a trickle tower containing DLS, and a diy skimmer (counter current). The trickle tower and skimmer were just added in the last few days to replace the two penguin bio wheels that are running on the tank. The substrate in the tank is only enough to cover the bottom as I had always read that deep sand beds were a negative thing in marine aquaria. Really regret that I didn't know about your site at the setup point, but I do plan on adding a good 3 inches of sand to the tank and the sump. <Good idea on the sand bed-deeper than 3 inches would-be even better.> The inhabitants are a pair of ocellaris clowns and a coral beauty angel, as well as a peppermint shrimp and a myriad of creatures that come out of the live rock when the lights are off:) Here's the problem- we just recently lost a very healthy (seemingly) Sailfin tang that we had for about 3 weeks or so. We found him lying upside down or on his side of the bottom of the tank gasping. The other fish were just fine. Every water parameter checked out accept the nitrates, which were in the 100 ppm range. <Yikes!> We've done a six gallon water change, and then another roughly one week later, but the nitrate remains the same. Thick clumps of emerald green algae appeared in different spots in the tank, but have now died back and been replaced with brown algae. Worrying profusely about her precious clown fish, my significant other has convinced me to do a massive water change to reduce the nitrates, as the smaller ones did nothing, and fearing her clowns will be lost to nitrate poisoning. At present, the water is mixing, but I fear that a large change (75% or so) will cause to great a shock to the fish and actually be their demise. <Better to perform smaller, regular changes> Also, the peppermint shrimp, a rock crab (in the refugium), and a tiny brittle star are all still alive and well- but I would assume that the nitrate level would do them in far before the tang? I sincerely appreciate you time, Thank you, Daniel <Your high nitrate level and algae bloom are indicative of a high nutrient level. There are somethings you can do to reduce this-adding a deeper sand bed, as outlined above, institute regular water changes, siphoning detritus as you go. You really should not use DLS material, or for that matter, bioballs, in your filters, as the DLS is a detritus trap, and the bioballs are essentially working against your deep sand bed by producing nitrate. Make sure your skimmer is adjusted to produce at least a cup of dark, yucky stuff weekly. And finally, if you really want to use Caulerpa in your sump, do harvest it regularly-a good source of nutrient export. Be careful not to rip the fronds while doing this. Keep reading on the wetwebmedia site for more information on maintenance. Good luck!- Scott F>

Nitrate and Clownfish Hello again! I hope this finds you all well. <Scott F. back with you again> I spent the day researching again, and decided on some "field work" to boot. I searched one of the LFS's that we like to use on occasion for more opinions (on your ideas) and for some comparison for my poor clown. I'm afraid I made a poor impression, but all is well that ends well, right? I told him of your suggestion for removing the bioballs upon addition (or a week or so after) of the DSB.....this had him pondering back and forth and finally he decided that he agreed with you, though he could not understand why it could not be a two inch sand bed, which I just had to let go, as I could not explain it to his satisfaction. That taken care of, I spotted several tanks of tank raised tomatoes and ocellaris that had some of the same markings on their white patches, which is what ours looked like at the start; I asked him what he could make of it, and I honestly believe that he had no idea, taking my "bait" with the marks having to do with the high nitrate levels....he was adamant that my clown's situation is indeed due to the high nitrates. I read every piece of Brooklynella information on WWM pages, and concluded that he is showing none of the symptoms for it. Still a mystery to me, any ideas besides Brooklynella? Daniel thinks that it could be Hole-in-the-head/HLLD...what do you think? <It's a distant possibility- this malady generally causes markings and/or pits in the skin due to skin loss; usually found near the no surprise here-head or lateral line area on the fish. It is rarely fatal, it just looks bad. All kinds of "remedies" exist for this malady, ranging from the addition of vitamins in the fishes' foods, to daily water changes, to grounding the tank from stray voltage, etc. This might even be "normal" coloration for this strain of captive-bred clowns?> I am very concerned even though he is still eating well, and behaving as usual. <Just keep a close eye on these fish and follow good maintenance practices. Be prepared to act decisively should the need arise>  The nitrates as of this afternoon are just under 20ppm by the way.) <definitely a positive trend. Good job!> I also asked him about the Caulerpa (which is all they sell) and if/when they might have other plant life available for us.....I'm afraid he thinks I'm crazy now, and we will more than likely not be using this store for any further saltwater related items. <Well, now you've crossed over that threshold into the realm of "fish nerd"-just like me, and there is no known no cure for that! :)> Our next research will be in the refugium section of WWM for better options. What *would* we do without you guys?! <Buy lots of Caulerpa, maybe? LOL> Thanks again immensely for your time, opinions and educated guesses. Kelly and Daniel in Houston <You're welcome. Feel free to contact us any time!>

Re: Bioballs, nitrates Hi Steve, Because bioballs *produce* nitrate waste, they do not consume it. This is okay for fish which can tolerate higher nitrate levels than inverts and corals. Removing the bioballs removes the problem, and the LR and DSB will process your nitrites into nitrate and nitrate into gas which then leaves the system. This is not possible with the added nitrates from the bioballs. Processing nitrite to nitrate is an aerobic process (requires oxygen) and processing nitrate to gas form is an anaerobic process (requires the absence of oxygen). Bioballs are bathed in oxygen, hence they only perform one part of the process. Does this explain it? For more check WWM, WWF, or Anthony Calfo's excellent book. I hope this helps! Craig

Nitrates won't come down Hi! <cheers> You have been very helpful in the past and I come to you with another query. I am having a problem with nitrates staying close to 100 ppm in my 75 gal marine tank. The tank has been set up since early May. It has a 3" sandbed and 150 lbs of Florida live rock.  <wow! Young tank... DSB and heavy live rock! Its unusual to have high nitrates in light of all of this. My first intuitive guess is that the sand grain is not fine (sugar/oolitic grade) or that it is mixed/coarse. Coarse sand grades are poor at denitrification and mist very very thick compared to sugar fine grades to work comparably. Over 5" thick needed here and very strong water flow in the tank is a must. Also, I wonder if you have been getting dark skimmate every day from your skimmer... a common flaw to not have a tweaked skimmer> I have a sump with an AquaC EV120 skimmer. No other filtration.  <no worries... plenty of rock and sand> The sump does have a coarse filter sponge in the baffle between the skimmer and the Mag 7 return pump. I clean the sponge about once a week to get rid of the detritus it catches.  <outstanding and little addition to nitrates here> I have recently also added a mesh bag with activated carbon. I am running two Maxijet 1200 powerheads in the tank for additional circulation.  <good move to keep detritus in suspension for skimmer> I have been changing 10 gal of water once a week (sometimes twice) in the last month and a half. This is about 15% of the actual water volume.  <perhaps larger water changes needed to keep pace> I use RO water from a drinking water machine at the local supermarket for all my water changes and top-offs. Using tap water results in fairly bad diatom blooms so I've never used any on this tank, not even for the initial fill. I just ordered an RO/DI unit which I expect to get next week. Nitrates had gone over 100 ppm (kit only shows 100 and 200 ppm) but the water changes are keeping them somewhere between 50 and 100 ppm according to my Salifert and Red Sea test kits. Nitrites are also between 0.1 and 0.2 ppm.  <that almost sounds like a misreading?!? I cannot fathom nitrites existing in this tank. Do confirm on another brand of test kit> Ammonia is 0. Ca is 450 ppm and Alk is 3.2 meq/l. pH is 8.3. I don't know why I can't keep nitrates (and nitrites) closer to 0. I think the tank has been up long enough for the nitrites to have gone down to 0. <agreed> A picture of my tank can be found at http://wetwebfotos.com/Home?actionRequest=userview&userID=819 but the tree sponges and gorgonians in that picture are now gone. I took them out after some comments from Anthony. the tank is stocked as follows: Fish: 1 Blue Damsel 2 Percula clowns 1 Royal Gramma 1 medium Purple Tang 1 Blue (Hippo) Tang - this is the largest fish at 3.5 to 4" < a fine selection of fishes and no significant source of nitrate here... at least nothing out of the ordinary. Still doubting test kits> Invertebrates: 1 cleaner shrimp 2 peppermint shrimp 1 coral banded shrimp 1 cup coral 1 frogspawn 1 hammerhead coral 1 brown zoanthid colony (turns white when the polyps retract) Misc mushrooms and polyps snails and miscellaneous life that came with the live rock and live sand from the Florida coast of the Gulf of Mexico. There are probably a dozen mollusks attached to the live rock, all live. <very cool> I've had the damsel, clowns and coral banded shrimp for about three years. They started out in a 10 gal tank. I feed the tank one cube of either Formula One or Formula Two thawed in tank water every two days and I also add a narrow strip of Nori a couple of times a week. Sometimes I feed a cube of frozen Mysis instead of the Formula x.  <all light feeding> I add DT's phytoplankton (about 15 ml, three capfuls) twice a week for the filter feeders. Could this regimen be the cause of my nitrate problem? <hmmm... perhaps a source indeed... take a capful in a sample of aquarium water and tees after some days... just for a ballpark idea on what a concentrated solution can do> Would it be OK for the fish to cut back further on the feeding?  <your feeding of fish and corals already seems light... cutting back should not be necessary> The food seems to be consumed very quickly. I wouldn't mind removing the hippo tang, since he's the dirtiest of the fish, but there's no way I can catch him without taking out a lot of the liverock and causing a major disturbance in the tank. <actually... the waste of these fishes is what in part will keep many of your corals alive unless they get target fed. The problem again is not your feeding amounts (modest). I'm wondering about skimmer performance or test kit accuracy> The livestock seems to be doing well but I am concerned about the coral's long term health since I read here nitrates should be kept at a minimum and certainly a lot less than 50-100 ppm. Based on what I've read it seems I should have a big algae problem, but I don't. There's some red algae that builds up under the sand level between the sand and the glass, but it is pretty light and there is nothing above the sand level. Running a stick between the sand and the glass gets rid of it immediately.  <very fine> I don't have any angel hair algae but the back panel of the tank is covered with small deep green dots and coralline algae that I want to let grow over the rear glass surface. Am I making too much out of the nitrate level I have?  <somewhat yes> I may start doing larger water changes,  <excellent> but I really would prefer to find the source of my problem and fix it there. <agreed... as per above suggestions> Thanks for any insights or suggestions you might have. Henry <best regards, Anthony>

Re: Nitrates won't come down Anthony: Thanks for the information. I don't trust the nitrite test either because the Salifert kit had them down at 0 before and the colors it produces are not the easiest to interpret, although it is clearly not 0. They don't quite match anything on the color chart. Unfortunately I no longer have the Salifert kit. I will get another one. The two nitrate tests I have (Salifert and Red Sea) do agree with each other so I think the nitrate readings are accurate. <interesting> Your guess about the sand is a good one. The sand is not particularly coarse but it is not oolithic either. It is straight sand from the Gulf of Mexico, similar what you find on the beach in Cancun or elsewhere in the Caribbean. Making it thicker in the main tank would be difficult because of all the live rock. <ahhh...understood> Would it help to add a 3 or 4" oolithic sandbed in the sump?  <yes... perhaps a refugium or sump with more than 4" of sugar fine sand will do the trick (denitrification) where coarse sand cannot. Unlit is fine with a good strong flow over it> If so, would it need special seeding or will enough life make its way to the sump from the main tank?  <just a handful of live sand to inoculate it would be enough> The sump area is dark. Lighting it might be an option but most of the sump area is taken up by the skimmer and pumps.  <no need... easier unlit here> I would also need to figure out some way to keep the skimmer pump submerged. There's a baffle right before the main pump and water is perhaps 8" deep. <all sump skimmers need a well or reservoir of their own (even a bucket with an overflow to drain in to the sump). It is critical; that a skimmer receives all raw overflowing water but it cannot be at the mercy of a fluctuating sump level (evaporation, etc) or skimmer performance will be compromised> The skimmer does foam all the time but it takes 2-3 days to reach the overflow outlet of the cup. I will adjust it to see if I can get more foam production.  <if the skimmer is sitting in the open sump, that may be a large part of the problem...see here: http://www.wetwebmedia.com/plumbingmarart.htm > I find I need to clean the pre-filter on the Mag 5 often to avoid pump performance from degrading. <the frequent cleanings are helpful but their need indicates a flaw in the system that allows such detritus to accumulate. Such matter should be kept in suspension for the skimmer to export. This does bring us back to water flow and skimmer performance needing tweaked> Is 50-100 ppm nitrate acceptable for the LPS and other invertebrates I listed?  <somewhat stressful but not fatal to many> I don't want to make too much out of these readings if my livestock is fine. I initially wrote because I thought I needed readings under 20 ppm. <indeed under 20ppm is recommended> Thanks again for your wonderful site and the help you provide. Henry <our great pleasure... thanks kindly. Anthony>

Re: Nitrates won't come down You are quick on the replies! <yes :) Here at WetWebMedia.com you have one of the rare exceptions of getting more than you pay for <G>> I am still confused about the cleaning of the pre-filters of the skimmer pump.  <no worries... I shall try to illuminate> The pump is right next to where the water comes from the tank into the sump. Anthony says: "the frequent cleanings are helpful but their need indicates a flaw in the system that allows such detritus to accumulate. Such matter should be kept in suspension for the skimmer to export. This does bring us back to water flow and skimmer performance needing tweaked". Since the pump is where the raw water comes in, that chamber contains detritus from the tank. That detritus gets trapped at the foam block on the intake of the skimmer pump (what I am calling pre-filter).  <yes! That is exactly the problem! Unless that foam block is cleaned daily in an attempt to prevent the biological nitrification of trapped waste... you have a filter that is generating Nitrates that could otherwise export said nutrients (raw water to the skimmer) BEFORE they have a chance to break down into nitrates> The pre-filter is meant to avoid any big items from entering the pump.  <that is the flaw, my friend... you want all raw organics...particulate and dissolved to enter skimmer with hopes of ending up in the skimmer cup BEFORE turning into nitrate in the system> Of course there's buildup there because the skimmer hasn't skimmed that water. Why wouldn't you expect this foam block to get this accumulation? Are you saying I should remove the pre-filter so the pump can push all the detritus into the skimmer?  <exactly... it is a common filter design flaw> I was just afraid something could make its way down from the overflow box in the tank and cause a problem in the skimmer pump, however, I now see where the pre-filter might be doing more harm than good.  <bingo, bub> There's also a foam block on the baffle before the return pump trapping this detritus, but some still makes its way to the other chamber, where it gets trapped by the pre-filter on the Mag 7 return pump. <this last stage polishing foam block isn't as bad as long as you clean it weekly or more often and it doesn't accumulate much. More often, I forgo it> Henry <best regards, Anthony>

Wet Dry Nitrate Factories? Hello Bob, I need some education regarding wetdry filters being nitrate factories but first the setup... 140 gal FOWLR with wetdry filter Aquaclear skimmer ~100 LBS live rock Inhabitants are an Emperor angel, Maroon Clown, Pacific Blue Tang, Convict Tang, Sailfin Tang, Scissortail Goby, Lawnmower Blenny, 2 neon gobies, plus some number of red tip hermits and turbo snails. This tank has been running for about a year. For maintenance I do a 20 gallon water change every 2 - 3 weeks and change the filter fiber, clean the skimmer etc. while doing the water change. My nitrate levels have always remained well below 10 ppm (I use the FasTest kit which has a lowest reading of 10ppm.) <Good maintenance, live rock... careful feeding...> >From what I have read from various sources, I should be pulling out my bio balls because the huge amounts of aerobic nitrifying bacteria growing on bio balls should be cranking out nitrate like crazy given the load on this tank. I'm struggling with this concept since it has always been my belief that the number of bacteria present is dependent on how much ammonia/nitrite is being produced. <One principal factor... as is a relative availability of aerobic, hypoxic, anaerobic space... detritus, circulation, types of foods...> If this is the case how would a wet dry system produce more nitrate than other types of filtration? <"Driving" the "forward" reaction of nitrification over its reciprocal complement (denitrification)... you may well have a relatively uncommon situation of "good" mix of livestock, feeding, upkeep, live rock, substrate... If you're satisfied with the under 10 ppm. nitrate readings in such a FOWLR system (I would be), then I wouldn't change much> Is it really just a maintenance issue of detritus collecting on the bioballs over time?  <These possibly, and other major to minor inputs> If you could either explain to me or point me to any information (books, articles, etc.) explaining how a wetdry filter can produce more nitrate than other filter systems I would greatly appreciate it? <... perhaps better to encourage you to do experiments... increasing the feeding, trying more frequent water changes... The energetics of the reaction series that yield more/less nitrate accumulation are straightforward... if there is more source material (ammonia, nitrite), less aerobic activity and/or more anaerobic digestion... the equation/balance of accumulated metabolites will/does shift from higher/lower. Do you want specific reference as in articles on biological filtration? What books, magazines do you have access to? I will take a look at what matches in our references. Bob Fenner> Thanks in advance,

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