denitrate canister. advice needed.

[firthy13]

im having nitrate dramas.

i have had a look in to this and i want to start another canister full of either matrix or seachem denitrate to try and get a good colony of anaerobic bacteria to consume nitrates.

i know to do this, a very low flow rate is needed as to provide a 'no oxygen' environment to the centre of each of the pieces of matrix or denitrate.

my question is:

how low is low?

would a 400 litre output ehiem be to much?

any advice would be much appreciated

[mcloughlin2]

First of how we need details of your tank setup.

How large is it? What type of fish and how many? What are your nitrate levels? Fresh or saltwater?

[firthy13]

sorry of cause you do.

ok, malawi hap/frontosa tank. about 15-20 at an average of 9-10 cm

holey rock and black 2mm substrate.

4x2x2, 450L

ammonia-0

nitrite-0

nitrate-20-80ppm

45-50% water changes every saturday

it gets to about 80 ppm at the end of the week

only feed 3 times a week.

[firthy13]

anyone

[Maskedman]

Sounds to me more like your filter simply isn't up to the job. What brand & flow rate is it? The large water changes will also be encouraging more nitrates as you are almost reseting the entire tank every time you do a water change that large. Meaning it is having to do a mini cycle every time you do a water change. Your tank is just below it's stocking limit & there is no way you can support all those fish in a tank that size as the grow larger, (Frontosas get to about 35cm). No matter how good your filter is.

Get a filter with a higher media volume for a start. That will increase the area that can be colonized by beneficial bacteria. Simply adding a second good canister filter is even better than replacing the one you have. That way you can clean one filter one week & the other a couple of weeks later. Meaning you will always have good bacteria populations.

Start doing smaller water changes. 20% every week. Twice a week if you have to. Smaller changes more often is more effective & better for your fish.

There will be populations of anaerobic bacteria already in your substrate in areas that are hard for you to vaccuum. You can also get a population of anaerobic bacteria in your existing filter simply by having some media in the middle that you allow to clog up & do not clean.

There is no need to have a filter just for anaerobic bacteria. If you need to look into things like that then your filter simply isn't up to the job your wanting it to do or your tank is over stocked. (I think you have both of these problems).

My first suggestion would be to get down to just 2 frontosa & maybe another 6 fish up to abut 15cm. That will solve most of your problem straight away. A better or bigger filter is what you need. Not anaerobic bacteria. Higher flow rate does not mean better filtration either, so don't get caught out. You are looking for filters with large media capacities & that the design of will force water through the media when it gets dirty, not around the media & thus not actually filtering the water.

[firthy13]

that explains alot. thanks alot.

well im onnly running an aqua one 1200. so yeh, too small.

so u reakon like an ehiem 2217 1000L would be enough or would u recommend something with an even greater volume?

well this nitrate problem has been going on for a while now, and i have recently just put new substrate in. only about 2 inches deep but.

when i clean the tank out i quiet vigerously clean my substrate with the gravel vac. would i be better off not stirring it up soo much?

[Ben]

Stop's replying on Aquaholics and starts here.....

I agree about you needing more filtration.... I do like the idea of two canister filters on larger tanks but you already know you need more filtration as you have been on the lookout for another filter for over a month now.

What media do you have in the Aqua One 1200? (just the stuff that comes with it?)

The reason I ask is I found replacing (or adding) quality media to my "cheap" canisters was required. The media that came with my Pro Aqua was not enough so I replaced it with Eheim media I had. It does a great job now but not so cheap a filter now with the cost of the media in it.

Large water changes I don't see as a problem as long as you are aging it and or using a good water conditioner. If you are gravel siphoning each time that's another story. Your substrate will hold a huge amount of bacteria. Especially 2 inches of it over a 4x2 area. However its going to take a few months to build up now that you have replaced it. Essentially you need to cycle the tank again to allow for the new substrate.. Keep up with the large water changes if you wish (increase fish growth etc) but just substrate siphon every few weeks.

Where did the nitrate problems start?

How old is the test kit you are using and have you tried another to ensure you not getting false readings?

Pop in and see Paul at Tank Aquariums and ask him to check it for you. Can't hurt to be certain.

Cheers

Ben

[firthy13]

i believe it started as i was getting to the end of stocking my new tank a few months ago. and they slowly keep increasing until about a month ago where it hit about 50-60ppm, hence when i started looking for a new filter.

i have 2 of the 3 trays full of ceramic noodles. and the other tray has the 2 sponges.

i have owned the test kit for about 12 months, but who knows how long it was on the shelf for before i got it.

ok well i think im going to put another canister on it this arvo, im just gonna bite the bullet and get an ehiem. mabye 2217? ill use the media that comes with that and after it has sufficient bacteria growth ill upgrade the media in my aqua one.

ill see how that goes.

in your oppinion do u think adding a 2217 would be enough, or would u reccomment going bigger volume??

cheers.

[Maskedman]

The Aquis 1200 is actually not too bad a filter & I have one on a 6x2x2 with about 50 africans in it & one on a 4x2x2 with half a dozen americans in it. The media that comes with the Aquis is good quality but it sounds like maybe you have it spread out very thin through the baskets or that you don't give the filter the occaional clean. I use the media that came with the filter but I put the ceramics & bioballs in the bottom basket. The two blue sponges in the middle basket & then the black sponge in the top basket topped up with filter wool before adding thier floss pad. I also use a $20 Vitapet 700lt/hr internal filter to help wiht suspended matter.

Anytime you clean your filter only clean the top basket thouroghly & the blue sponge closest to the bottom. Switch the cleanest blue sponge to the bottom & clean the other one placing it on top of the dirty sponge when putting the filter back together. Rinse the bottom basket with the dirty water in the filter. NEVER clean the bioballs & ceramics under tap water & NEVER wash them clean. That dirty stinky stuff is your bacteria population.

The filter should be up to the task so long as you don't let it clog & you get rid of the excess fish in the tank. Only vaccuum the top 1-2cm of your substrate & it will be fine to use the vac with every water change. You will only have problems if you are burying the vac all the way down in the gravel & sucking up the good bacteria that way.

Keep in mind that media volume is the most important thing with any filter if you are going to add a second one. Personally I think the filter should be up the job just fine & that the problems are caused by overstocking & the large water changes combined with a low bacteria population in the substrate.

To increase bacteria population you could simply add a large external PVC chamber inline on the pickup pipe (below water level), & fill that with bioballs. Make sure that air cant get trapped in the chamber & you will be away. I have one of these chambers on another 6x2x2ith a little 500lt/hr canister & it does an amazing job of breaking everything down. I would go as far as saying that short of a Ehiem Pro 3, nothing on the market is as effective as the PVC chamber I use. Cost me $80 including the bioballs.

Regardless, adding a second filter is going to be a good thing & you can't really go wrong with an Ehiem. Just arrange the outlets so that you don't wash your fish away with the current. I would get those water changes up to twice a week until you get the problem sorted out too. Even if you can only do an extra 10% change one night after work it will help out alot. The larger water changes shouldn't be a problem once your bacteria population has itself established properly.

[Rod54]

Here's an alternate opinion..

There's nothing wrong with your filtration....it would seem that a large increase in nitrate each week indicates your biological filtration is doing it's job....converting ammonia to nitrite to nitrate

Extra filtration will not solve your problem(personally I believe that most of the biological filtration is done by bacteria on hard surfaces in the tank) biological filtration is most efficient at low flow rates...that's why air driven sponge filters do a good job!

Test you tap water....perhaps it is high in nitrates....if it is....keep water to be used for changes in a tub covered in duckweed....it will grow like mad remove nitrates and be good food for your fish!

If not do 3 or 4 50% water changes each week until your nitrate is low

Water changes with zero nitrate water is best solution

Just for the record.....Aerobic bacteria form a biofilm....the older the colony the thicker the biofilm....a quick clean under tap water will not kill significant number of bacteria in a well established tank....and as most of it in in the tank anyway!!! These little buggers wouldn't have survived for millions of years if they were easy to kill!

It is better to clean all rubbish from your filter so it can do it's main job....mechanical filtration

I'd also give the gravel a Good vac each water change....different if plants were there to use nutrients

[Aquaholic]

Here's an alternate opinion..

There's nothing wrong with your filtration....it would seem that a large increase in nitrate each week indicates your biological filtration is doing it's job....converting ammonia to nitrite to nitrate

Extra filtration will not solve your problem(personally I believe that most of the biological filtration is done by bacteria on hard surfaces in the tank) biological filtration is most efficient at low flow rates...that's why air driven sponge filters do a good job!

Test you tap water....perhaps it is high in nitrates....if it is....keep water to be used for changes in a tub covered in duckweed....it will grow like mad remove nitrates and be good food for your fish!

If not do 3 or 4 50% water changes each week until your nitrate is low

Water changes with zero nitrate water is best solution

On the money IMO!!!

[mcloughlin2]

You can add as many cannister filters as you want on the tank - all they are going to do is convert ammonia - nitrite - nitrate faster. Cannisters due to their high flow rates do not allow for an anoxic environment (No oxygen), hence oxygen loving bacteria known as aerobic bacteria flourish in cannisters while there is virtually no sign of anaerobic bacteria. It is the anaerobic bacteria that convert nitrates into nitrogen gas which diffuses into the air. This is why cannisters are good and bad filters. They are efficient at completely the first part of the nitrogen cycle but they act as nitrate builders so essentially they cause high levels of nitrates.

The only reliable proven method to remove nitrates in freshwater tanks are algae scubbers. Do a search on them. They are very cheap to build and are guaranteed to work. There are also numerous products you can by that rely on pumping water very slowly through media in the hope that aerobic bacteria will grow in the beginning of it and consume all the oxygen so anaerobic bacteria can live at the end, however these I have been told are not very effective and they cost a pretty penny.

As I said you do not need to put another filter on, rather if your concerned about nitrates find methods to increase your anaerobic bacteria numbers. If you did go out and buy another filter, don't stress because it won't hurt. However it will do nothing to solve your nitrate problems.

[CThompson]

Rod and Ben are giving good information. But there is a lot of other stuff that stands out to me that I would like to address before I answer the question that was asked.

The large water changes will also be encouraging more nitrates as you are almost reseting the entire tank every time you do a water change that large.

Absolutely and totally untrue. Large water changes provided the water is preadjusted to match what the tank is for such parameters as pH KH temp, conditioners etc have nothing but positive impacts. The KEY here is that it MUST be fully preadjusted before it is put in (easy to do with water change barrel/container). W/C were the traditional and principle and still most widely used method of limiting nitrate levels - by exporting them. Larger W/C = more nitrate removed – it's as simple as that.

only feed 3 times a week.

Not enough food. I understand your approach trying to limit the end result of nitrate. Use NLS – a food that is more fully digested = less waste = less nitrate.

NEVER clean the bioballs & ceramics under tap water & NEVER wash them clean. That dirty stinky stuff is your bacteria population

While I agree with not cleaning under tap water, you absolutely can and indeed should clean the bio media. Use the water exported when water changing. That "dirty stinky stuff" is…dirty stinky stuff. At best the biofilm if it can be seen may be seen as an opaque smear on glass, on biomedia you will very likely not see it. The "dirty stinky stuff" is in fact hampering the bacteria's access to O2 and their food (ammonia and nitrite). Treat it as rough as you like - clean in tank water and don't let it dry out.

Personally I think the filter should be up the job just fine & that the problems are caused by overstocking & the large water changes combined with a low bacteria population in the substrate.

By having zero ammonia and nitrite you have clearly got enough surface area, otherwise it wouldn't be zero. FYI as bacteria require O2, the population existing in the substrate will be limited by its access to O2 (different with an UGF). That is the deeper you go the less aerobic bacteria there will be. That is why we have bio media in our filters as this will "push" all resources needed to support a bacterial colony, ammonia, nitrite and O2 to the bacteria.

Extra filtration will not solve your problem(personally I believe that most of the biological filtration is done by bacteria on hard surfaces in the tank) biological filtration is most efficient at low flow rates...that's why air driven sponge filters do a good job!

Bacteria it is true need a hard surface, but this is fairly limited inside the fish tank, that is why we use biomedia (in sufficient quantities). Flow rates are important but a fast flow rate will not restrict the bacteria and in fact will in all likelihood assist them as it will bring a greater quantity of O2. If the flow is too fast for the bacteria to FULLY assimilate the waste, it will get it in the next pass, or the next or the next. In effect, wether the flow is fast or slow, if ammonia is passing the bacteria the bacteria are consuming it, a fast flow will not hinder this, and will bring more O2.

The only reliable proven method to remove nitrates in freshwater tanks are algae scubbers.

Completely untrue. There are chambers filled with Seachem Denitrate (denitrate filters) and a new product (well – new to Oz) called Revolution coming to Australia (info@aquapremium.com.au) that will do the job equally well if not better than a properly set up denitrate filter.

im having nitrate dramas.

The first thing you need to do is confirm your nitrate test kit results.

The next is to work out where the nitrates are coming from. What is the nitrate reading of your tap water? Is the nitrate leaching out of rocks or substrate in the tank? Is the food you are using high in nitrate? If you are only feeding three times per week (not enough as I've already said) I don't think you can immediately blame the food.

i have had a look in to this and i want to start another canister full of either matrix or seachem denitrate to try and get a good colony of anaerobic bacteria to consume nitrates.

Don't use Matrix –Do use a canister filled with Denitrate. Water must be VERY clean before it enters chamber. Flow rate = 20 gph (I do less). This comes out quite fast.

You will probably need to use an old style canister (the ones where the motor is separate from the canister), or make your own using PVC piping, and use the smallest Ehime Hobby Pump (1048 from memory) and even with this you will have to "T" off the water to limit the flow through it.

You could put the denitrate chamber/filter in line with an existing canister provided you "T" off the existing canister return water to adjust flow rate through denitrate chamber. You can buy in line flow meters to easily monitor flow through denitrate chamber.

Craig

[Maskedman]

True about large water changes being ok, so long as all the parameters & temp are set first. Unfortunately in the real world very few people are set up with a seperate tub to treat thier water first. Far more likely that the water is being bucketed in after being dechlorinated. Safer to assume that's the way it is. That way that cause can be eliminated altogether.

Fact, like it or not, the substrate was replaced recently & has been very thoroughly vaccuumed at each water change. There is not much of bacteria population of any sort in that. I do agree that the substrate is limited by how much oxygen penetrates it.

I should have been clearer on my filter cleaning instructions. When I say don't clean the Bioballs etc, I mean do not scrub them clean. Rinse them in the water that is already in the filter body as you remove the baskets. (works great doing it that way with the Aqua One design).

That make you happier CThompson?

The tank is WAY overstocked, (do the math on the surface oxygen supply) That, IMO is part (large part), of the cause of your nitrates rising so high so fast. It's just waste being created faster than the filter can deal with it from such a small body of water. The smaller the body of water the faster all polutant levels rise for a given number of fish. Eg - 20 fish will pollute 250lts much faster than they will pollute 600lts. How good or bad a filter is does not effect this fact.

I might not know all the fine details of some of the experts on here but then I only use the identical filters on more heavily stocked tanks with absolutley no problems whatsoever. Don't let people make things seem more complicated than they really are.

K.I.S.S. (Keep It Simple Stupid)

PS - I may be new to computers & the internet but I have been keeping fish for well over twenty years & currently have over 30 tanks with more than 2000 fish.

[mcloughlin2]

You said

a 6x2x2 with about 50 africans in it & one on a 4x2x2 with half a dozen americans in it

He has a 4x2x2 with 20 africans in it. If you do the maths your tank is far more overstocked. I have had over 50 africans in a standard 6ft tank with no problems. If you have no surface disturbance sure you need to make sure the tank is understock but if you have an airstone in the tank that significantely increases the amount of oxygen diffusing into the water.

The issue with most of what was you said Maskedman was that it was untrue. The fact there are high levels of nitrate proves that there is a sufficient population of bacteria. As I said fish produce waste as ammonia, which aerobic bacteria convert to nitrite and then nitrate. If there was no bacteria in the tank because he was siphoning them out then there would be high levels of ammonia and next to no nitrate.

[Rod54]

I agree with mcloughlin2

Test your tap water....it's probably high in nitrates

Add more filters if you like.....wasting money IMO

Craig does have the experience with denitrators....but so do I (duckweed!)

In the end if ammonia is 0 and nitrate 0 then it doesn't matter where the bacteria live.....there is enough somewhere to do the job...and it is.....extra filtration will not reduce nitrates

[Maskedman]

You said

a 6x2x2 with about 50 africans in it & one on a 4x2x2 with half a dozen americans in it

He has a 4x2x2 with 20 africans in it. If you do the maths your tank is far more overstocked. I have had over 50 africans in a standard 6ft tank with no problems. If you have no surface disturbance sure you need to make sure the tank is understock but if you have an airstone in the tank that significantely increases the amount of oxygen diffusing into the water.

The issue with most of what was you said Maskedman was that it was untrue. The fact there are high levels of nitrate proves that there is a sufficient population of bacteria. As I said fish produce waste as ammonia, which aerobic bacteria convert to nitrite and then nitrate. If there was no bacteria in the tank because he was siphoning them out then there would be high levels of ammonia and next to no nitrate.

Assumption is the mother of all F ups. Your assuming I have large fish, like Frontosas, which I do not. Not in this tank anyway. Seems I'm the one that pointed out that the filter was up to the job & not to worry about this anaerobic filter stuff. Extra filtration never goes astray & the initial question is about filters. I would also bet that nearly every person on this site would recommend buying an Ehiem filter to anyone who has filters of lesser quality.

I never stated that there was not sufficient bacteria. That is the claim made by the author of the post. At least get that right. Advice was given on filtration options as that is what was asked for. The next fact is that more frequent water changes are the best answer to the problem short of having less stock. Duckweed will get eaten by most africans like it is food so it's usually a waste of time trying it in the first place. Using chemicals is not the right answer. As everyone knows finding the underlying cause of the problem is always far better. Now I bet if the nitrates were rising at the sort of rates posted in one of your own tanks, you would look at the stocking levels of the tank first & realise that the fish were creating waste too fast. The next thing you would do is increase the frequency of your water changes. As for more evidence of over stocking all you have to do is imagine 2 x 30cm Frontosa in with another 15 or so 15cm fish. You can't possibly condone that many fish of that size in a tank that small. Poor fish would be running into each other all the time.

Get off your high horse & go back to Aquarium Maintainance 101.

[Maskedman]

By the way if you don't like my posts. Tough.

People such as yourself are missing out because you are convinced that your way is the only way. Sorry but your way is not the only way. Get over it.

I won't be using this forum anymore as I can't even post pics but I have no trouble on other sites. I will check in in a few days to see your reply.

Adios & happy fish keeping.

[fongyfong]

By the way if you don't like my posts. Tough.

People such as yourself are missing out because you are convinced that your way is the only way. Sorry but your way is not the only way. Get over it.

I won't be using this forum anymore as I can't even post pics but I have no trouble on other sites. I will check in in a few days to see your reply.

Adios & happy fish keeping.

If you wanna upload pictures do this

Go to my controls

Your albums

upload image

then copy the shortcut link of your album and put it below between the img and when you type remeber no spaces with the img code

[ img ].......... the link goes here[ /img ]

[fongyfong]

and it should come out like this

[Rod54]

Maskedman.....mate

This is a forum about a hobby we all enjoy....don't let it upset you if others don't agree with your proposals,

Craig often disagrees with me even though I'm always right!

by all means argue your case...I do

This should be about sharing information and ideas....none of us (except me) are right all the time!

[Maskedman]

Maskedman.....mate

This is a forum about a hobby we all enjoy....don't let it upset you if others don't agree with your proposals,

Craig often disagrees with me even though I'm always right!

by all means argue your case...I do

This should be about sharing information and ideas....none of us (except me) are right all the time!

I've got no problem with differing opinions. Only with arrogance. I also have no problem arguing my point, but given that I am changing my main forum because for some reason I can't post my pics & that I have already given my advice, I see no need to argue the point any further.

Thanks to all those who have been helpful on this site.

[CThompson]

I've got no problem with differing opinions. Only with arrogance.

It's an interesting psychological trait that humans have in targeting/accusing an individual of having "such and such " fault, when in fact that is a trait that we ourself have and are unaware of.

The only arrogance I read was in your posts

For my part I wrote a quick reply that you may have incorrectly perceived as arrogant, due to time constraints (at work) and the fact that I have said it all before and try to "get the information out" as easy for me as I can. Unless a post is in your face arrogant - much like yours became, you can't take much more out of written information further to what is actually written.

You made some comments that were clearly incorrect, such as;

Sounds to me more like your filter simply isn't up to the job.

If there were high ammonia and nitrite reading then this would indicate that the filter was inadequate. In this case it is high nitrate readings. This has either come from the tank's cycling (in which case the biological side of the filter is working great) or the nitrate has been imported into the tank with the water in the replacement water change water . OR there is something in the tank that is leaching nitrate

In all these cases, the nitrate has NOTHING to do with; "filter simply isn't up to the job".

You also said;

The large water changes will also be encouraging more nitrates as you are almost reseting the entire tank every time you do a water change that large.

Large water changes will not and cannot "encourage" nitrates (unless there is nitrate in the replacement water as I mention above).

You also said;

Meaning it is having to do a mini cycle every time you do a water change.

That is silly, and coupled with your above comments clearly indicates that for all the years you have kept fish you clearly don't understand something as simple and basic as a tank's cycling process.

The tank's stocking level may be the cause of the high nitrate readings. However, firthy13 was asking about a way of obtaining "colony of anaerobic bacteria to consume nitrates". The two ways that I know of doing this to an effective degree is to use a chamber filled with Seachem Denitrate or with "Revolution" if and when it becomes available. Marine people are fond of algae turf scrubbers which will remove nitrates the same way as Rod's duckweed.

I personally like to understock, but if firthy13's fish are living together okay, AND he can find a way to drop nitrates, his first solution is to do what his questions are asking about. Failing that, if the nitrates are the end product of a tanks cycling due to the bioload, then he could start to think about reducing the population – or moving to a bigger tank if that is viable.

Remember here to, that he is only feeding three times a week, and though it is not mentioned what is fed, I would have to be first convinced that the nitrates are coming from the tanks cycling which in effect starts with the food put in. That is, if fish aren't pooping (much) there will be a corresponding lower nitrate build-up. He has high nitrates – from feeding the fish??? I suspect the high nitrates are caused by too many fish by the way.

PS - I may be new to computers & the internet but I have been keeping fish for well over twenty years & currently have over 30 tanks with more than 2000 fish.

What's that got to do with it? I've had fish since my age was in one digit (my first word was "shish") and I'm now 46, I've got around 4000 litres of water and more fish than I can count.

I never stated that there was not sufficient bacteria. That is the claim made by the author of the post. At least get that right.

The "claim" as you put it by the "author" (firthy13) was in fact about high nitrates and a way to get rid of them with anerobic bacteria– "at lease get that right"

As everyone knows finding the underlying cause of the problem is always far better.

True, but that is not what you have done.

I won't be using this forum anymore as I can't even post pics but I have no trouble on other sites. I will check in in a few days to see your reply.

That's the best thing you've said so far – Good luck to those you post to in the future.

What firthy13 probably will be best doing, is as you say, reduce fish numbers OR get a bigger tank. He may be effective in reducing nitrates however if a nitrate reducing stratergy/equipment is used. He should also look at starting a new thread explaining how his filters are stacked and getting advice making sure there is a biological section within the canister.

As for myself I won't be coming back to this thread.

[Citypainter]

The moral to the story.

If Craig gives you a short answer.

Be grateful.

Never argue with a scientist

[Maskedman]

You mean never argue with someone who has a superiority complex.

Do me a favour & cancel my membership. I have now read the answer I was waiting for & have no use for this forum anymore. Thank you.