High Nitrates -- only in my tanks with a canister filter

LHanna61

Hi Everyone--
I am simply perplexed.
I have 5 tanks and 1 bowl.


1. My bowl has no filtration, with a few fry at any given time (currently just one) and 5 shrimp
2. I have a 20 gallon on a canister filter
3-5. I have three 10 gallon tanks, two on submerged filters and one on a canister filter
6. Lastly, 5 gallon on a submerged filter

Long story short-- the two tanks I have set up on canister filters have extremely high Nitrates ALL the time. No matter what I do.
The 20 Gallon is stocked appropriately with maybe 12 dwarf rasboras and 4 corydoras, 2 mystery snails. The canister is rated at 350+ GPH. My ten gallon with the canister (250 GPH) has a small colony of blue shrimp and 2 nerite snails (that's it!)

I've gotten into the habit of feeding SUPER small amounts every 2 or 3 days because of the nitrates. (I stopped feeding the 10 gallon all together) I just can't keep them down!

I've done a few 50% water changes on the 20 gallon, I've done a few 30% on the 10 gallon (trying to avoid shocking the shrimp) and that works for a day (two if I'm lucky) and then it's right back up to 40-80 ppm.

I've obviously gone about cleaning the filtration media (in dirty tank water) and I've also cleaned the tubing with a pipe cleaner (previously recommended to me).

Every time I do a water change, I make sure to clean the substrate (a mix of eco-complete and fluval stratum). It never seems too dirty. I've even tried stirring the substrate up to be extra thorough.

Any tips are appreciate here.

Note: I know it's not a bad API (liquid) test I've been using because I check all my tanks at the same time and it's only those two that come up stupid high.
 

gray_matter16

First thing I would test is your tap water, or whatever water you're using to replace water during water changes. Check that water's ammonia, nitrite, and nitrate- let us know what the readings are.

Assuming your replacement water is relatively normal, my next question would be about live plants? Other than water changes, do you have anything that is consuming or taking away the nitrate (like live plants would)? If you don't have plants or anything consuming the nitrates, and your replacement water has normal levels, then I think frequent and consistent water changes is your only option. "Frequent and consistent" to me would be a 50% water change every 2 or 3 days until the levels are back down. And then figuring out a water change schedule to keep them there (this is all dependent that your replacement water levels are normal).

If you have live plants, or are willing to get them, that could be another way to deplete nitrate levels.
 

LHanna61

First thing I would test is your tap water, or whatever water you're using to replace water during water changes. Check that water's ammonia, nitrite, and nitrate- let us know what the readings are.

Assuming your replacement water is relatively normal, my next question would be about live plants? Other than water changes, do you have anything that is consuming or taking away the nitrate (like live plants would)? If you don't have plants or anything consuming the nitrates, and your replacement water has normal levels, then I think frequent and consistent water changes is your only option. "Frequent and consistent" to me would be a 50% water change every 2 or 3 days until the levels are back down. And then figuring out a water change schedule to keep them there (this is all dependent that your replacement water levels are normal).

If you have live plants, or are willing to get them, that could be another way to deplete nitrate levels.
Thanks for the thoughts-- I use remineralized RO water and I just tested the levels and they are literally all zero.
Keep in mind, it's ONLY on the tanks with canister filters-- that's the main thing

All my tanks are fully planted tanks, my 20 Gallon has a CO2 setup and everything. They aren't 'lush' or anything but I've go enough live, well rooted plants where I would have thought they would be perfectly fine absorbing everything.
 

gray_matter16

Thanks for the thoughts-- I use remineralized RO water and I just tested the levels and they are literally all zero.
Keep in mind, it's ONLY on the tanks with canister filters-- that's the main thing

All my tanks are fully planted tanks, my 20 Gallon has a CO2 setup and everything. They aren't 'lush' or anything but I've go enough live, well rooted plants where I would have thought they would be perfectly fine absorbing everything.
Yeah all that sounds like it should. What are in your cannister filters? The only thing I can think of is a major build up of detritus in the filter's sponges or filter floss. That happens to mine occasionally. And I just replace them with fresh ones. I never replace the bio-media pellets and lava rock I have, but do replace the filter floss and sponges in my cannister filters when they are very dirty and saturated.
 

carsonsgjs

How often do you clean out your canisters? Do you use any fertilisers too?
 

LHanna61

Yeah all that sounds like it should. What are in your cannister filters? The only thing I can think of is a major build up of detritus in the filter's sponges or filter floss. That happens to mine occasionally. And I just replace them with fresh ones. I never replace the bio-media pellets and lava rock I have, but do replace the filter floss and sponges in my cannister filters when they are very dirty and saturated.
I have been cleaning them every 3-4 weeks just because of the nitrates really frustrating me, I've tried adding new floss, rearranging the media baskets, putting less media, more media, and again, i cleaned the tubing recently as well.

The canisters are both Cascade canisters (different models but same company). I have had them for a while and haven't had any issues up until now.
How often do you clean out your canisters? Do you use any fertilisers too?
See my other comment about cleaning the canisters-- I recently started adding fertilizers because some of my plants were looking a little blah (which was shocking because they should be absorbing the nitrates for their nutrients!) Only this past month did I start and it's the aquarium co-op easy green (all-in-one)
 

RayClem

Do you use prefilter sponges on the intake tubes of the canister filters? If not, I would suggest you get them These sponges will trap a lot of the debris before it ever enters your canister. Clean the sponge frequently.

What type of filter media do you use in your canisters? Sponges are nitrate factories because they are great for nitrifying bacteria, but not for denitrifying bacteria. Media with small pores will allow for both types of activity, That includes natural materials like lava rock and pumice. Seachem Matrix and deNitrate are pumice. Perlite is another volcanic mineral that can be used. An effective, but expensive, manufactured media is Biohome. I have some Biohome Ultimate in my canister.

Since your substrate is not getting dirty, I would suggest that you leave it alone. Undisturbed sand beds often have anaerobic layers that allow for denitrifying activity. By stirring up the sand, you are introducing oxygen which interrupts that process.
 

jtjgg

canisters are usually referred to as "nitrate factories."

you might try cleaning the canister filter pads every week and see it that makes a difference. all that poop trapped inside for several weeks continues to generate nitrogenous wastes resulting in higher nitrates.

this is from a Tidal 110 hob after 1 week, imagine after 4 weeks or longer:


full?d=1569957187.jpg
 

gray_matter16

I ran two cannisters on my 75 gallon tank and never went over 10ppm in nitrate. But the tank was filled with a dense vallisneria jungle plus I had huge pothos roots which is another plant notorious for consuming nitrates well. You might want to try getting your tanks with cannisters even more densely planted- especially with fast growing varieties (most stem plants).
 

leftswerve

Are you using the ferts in all tanks?
You aren't changing enough water to lower the nitrates enough. More PWC.
 

LHanna61

Thanks everyone for the feedback!
Just to answer a few questions, yes my tanks are planted--
1. I would like to add more but I'm concerned that the ones I already have aren't growing 'lush' enough considering how much nutrients I am giving them (without over fertilizing). I have some pothos in my tanks as well-- that doesn't seem to be helping much unfortunately.
2. My canisters have a combination of media, I have some bio rings and bio balls in them in addition to the sponges they come with (that have also been cleaned). I have noticed the filter floss (white sponges) get extremely dirty very quickly-- should I just take those out and use more 'hard' bio media?
3. I want to avoid cleaning the canisters weekly because they just make a mess and I put them in places where they are out of sight (i.e. not that easy to unhook and hook back up frequently).
4. I do have pre-filter sponges on both canisters and I squeeze them out with every water change. I ACTUALLY recently took the 20 Gallon off and put a media bag over the intake feature just to see if the sponges were causing water circulation issues but that didn't seem to change my results much (maybe added one extra day before the nitrates increased to red zone).
5. I'm hesitant to do a lot of partial water changes on the 10 gallon because it only houses shrimp and I don't want to shock them so perhaps I can relocated them (after acclimating carefully of course) to a tank that isn't having this issue. I would like to avoid that if the solution is more simple but I will do what needs to be done at the end of the day.


I appreciate any additional thoughts!
 

leftswerve

IMO, stick with the fine sponges or change to floss, it is polishing the water and getting fine particles out (as the larger bits break down). IMO, when you make water change water, make more than you need, let it sit circulating until you need it for a PWC. It's the same water right? Just make sure the temp is close. Also, don't rule out the ferts you're using causing your issues.
 

jtjgg

2. My canisters have a combination of media, I have some bio rings and bio balls in them in addition to the sponges they come with (that have also been cleaned). I have noticed the filter floss (white sponges) get extremely dirty very quickly-- should I just take those out and use more 'hard' bio media?

5. I'm hesitant to do a lot of partial water changes on the 10 gallon because it only houses shrimp and I don't want to shock them so perhaps I can relocated them (after acclimating carefully of course) to a tank that isn't having this issue. I would like to avoid that if the solution is more simple but I will do what needs to be done at the end of the day.

2. you must have at least 1 tray of sponges to catch all the solid wastes or it'll clog up the biomedia.

5. you might upgrade to a larger tank. the larger the water volume, the more stable it'll be.
 

LHanna61

I think I'm going to end up just ditching the canisters and putting in submersible filters like my other tanks. The canisters were supposed to be easier and they were for a while! But they seem to be causing more issues and I'm worried about the health of my fish now. I'll double up for a bit and see if that helps.

Thanks for the feedback everyone!
 

RayClem

There is nothing wrong with canister filters themselves. If they did not work well, those with large tanks would not use them.

I am like you in that I hate cleaning the canister itself. Prefilter sponges come in a variety of sizes and coarseness ratings. If your current prefilter is not doing its job, you might need to try another type.

Remember that there are only two sources of nitrogen inputs to your tank. One is the protein in the food you are feeding your fish. Are you feeding your fish too much at one time or more frequently than necessary? The protein in the food you add to the tank will end up as either muscle mass in the fish or as nitrates. Either reduce your feeding frequency or reduce the amount you are feeding at each session. Some people intentionally skip a feeding or two. Overfeeding your fish is more harmful than underfeeding them.

The second source of nitrogen may be from the plant fertilizers you use. What type of fertilizer are you using? If your nitrates are high and your plants are not growing sufficiently, the you have not achieved a proper balance of light, carbon dioxide, and nutrients. Since your nitrates are high, you do not need to be adding all-in-one type fertilizers that contain nitrogen compounds in the form of urea or nitrates. However, you might need to be adding micronutrients and potassium.
 

Ksway

How many ml are you doing of ferts? What type of light (how many watts and light cycle time) and plants do you have. Issue is possibly the ferts are adding too much nitrogen and it is not getting used up by plants. I keep hi tech planted tanks with canisters without any nitrate problems I dose 6ml of tropical ferts a day 3x recommended dose on bottle without issue of nitrates. I'd say it is an imbalance issue. Or as someone mentioned above food could be getting stuck in cannisters. I add as much bio media as possible and just use filter floss in top tray which I replace every week. I clean filter media every 6 weeks with tank water.
 

LHanna61

There is nothing wrong with canister filters themselves. If they did not work well, those with large tanks would not use them.

I am like you in that I hate cleaning the canister itself. Prefilter sponges come in a variety of sizes and coarseness ratings. If your current prefilter is not doing its job, you might need to try another type.

Remember that there are only two sources of nitrogen inputs to your tank. One is the protein in the food you are feeding your fish. Are you feeding your fish too much at one time or more frequently than necessary? The protein in the food you add to the tank will end up as either muscle mass in the fish or as nitrates. Either reduce your feeding frequency or reduce the amount you are feeding at each session. Some people intentionally skip a feeding or two. Overfeeding your fish is more harmful than underfeeding them.

The second source of nitrogen may be from the plant fertilizers you use. What type of fertilizer are you using? If your nitrates are high and your plants are not growing sufficiently, the you have not achieved a proper balance of light, carbon dioxide, and nutrients. Since your nitrates are high, you do not need to be adding all-in-one type fertilizers that contain nitrogen compounds in the form of urea or nitrates. However, you might need to be adding micronutrients and potassium.
I know canisters work because i never had an issue like this until recently. I definitely don't want to keep cleaning it weekly because that defeats the purpose of having a canister filter (in my opinion).

I've been feeding pretty high protein food but again, i don't have this issue in my tanks without the canisters. Same goes for the fertilizers. All my lights are specifically chosen for plant growth and my 20 G has a CO2 tank on it. I could look into focusing on micronutrients but I'm not sure what the best route is for that-- I can't tell what my plants need, they are just incredibly slow growing (even with the CO2).

I also noted previously that I've been cutting back on my feedings significantly. So I'm feel the only issue is my canisters. Is it possible that the water flow isn't fast enough? and they're clogged somewhere else besides the sponges?
How many ml are you doing of ferts? What type of light (how many watts and light cycle time) and plants do you have. Issue is possibly the ferts are adding too much nitrogen and it is not getting used up by plants. I keep hi tech planted tanks with canisters without any nitrate problems I dose 6ml of tropical ferts a day 3x recommended dose on bottle without issue of nitrates. I'd say it is an imbalance issue. Or as someone mentioned above food could be getting stuck in cannisters. I add as much bio media as possible and just use filter floss in top tray which I replace every week. I clean filter media every 6 weeks with tank water.
Per the instructions on the bottle I use, it says "one squirt" per 10 gallons once a week so I'm not entirely sure how many mLs that is-- I can measure it if you think it's helpful.

Thank you for providing the schedule you clean your filter with-- mine is just such a hassle to take apart I don't feel it's worth doing weekly maintenance on-- i feel it's easier to get a smaller filter that I don't need to take apart.

I've had these canisters setup for 1.5 years and only in the last 5 months has it become a problem-- i think you're right about the food.

I've been favoring the use of "Shrimp Baby" food from Glas Garten and I feed A LOT less then it recommends (like half a pinch in each tank vs one full scoop)

I also feed other foods but that's the main one i use because all my fish are dwarf size and it's obviously good for my fish
 

Ksway

Yes I agree cleaning filters every week is a pian, I don't clean them every week I just take the top filter floss out and replace it (this is more for plants as I dont want algae). How many watts are your lights? If you could dose daily it would be far better, as you wouldn't be adding a weeks worth of nitrate in one day. The plants won't use all of it and it will just sit in the water column. Where as daily the plant use it all up and you add more. What type of plants (pictures? ) If they are slow growers they might not need much ferts at all. Also have you cleaned the propeller on the canister filter? People often forget that and it gets clogged which stops the flow rate as you were mentioning above
 

LHanna61

Yes I agree cleaning filters every week is a pian, I don't clean them every week I just take the top filter floss out and replace it (this is more for plants as I dont want algae). How many watts are your lights? If you could dose daily it would be far better, as you wouldn't be adding a weeks worth of nitrate in one day. The plants won't use all of it and it will just sit in the water column. Where as daily the plant use it all up and you add more. What type of plants (pictures? ) If they are slow growers they might not need much ferts at all. Also have you cleaned the propeller on the canister filter? People often forget that and it gets clogged which stops the flow rate as you were mentioning above
hahah "just take out the filter floss"-- that's so hard to do hahah

As for my lights--
My 10 G with the issues has a "MingDak Fish Tank Clip on Light with Inline Timer, Clamp Aquarium Light with White & Blue LEDs, 3 Lighting Modes, Dimmable, 10W, 27 LEDs"
My 20 G with the issues has a "NICREW ClassicLED Aquarium Light, Fish Tank Light with Extendable Brackets, White and Blue LEDs" this one is 18W.

Attached are pictures of my tank as it is right now. Like I said, the plants seem to be stunted so any suggestions are appreciated.

As for the propeller-- I stuck the pipe cleaner in there but I wasn't sure if that was okay to do so I didn't clean it thoroughly-- I can try doing that today and see if that helps any.
 

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Ksway

hahah "just take out the filter floss"-- that's so hard to do hahah

As for my lights--
My 10 G with the issues has a "MingDak Fish Tank Clip on Light with Inline Timer, Clamp Aquarium Light with White & Blue LEDs, 3 Lighting Modes, Dimmable, 10W, 27 LEDs"
My 20 G with the issues has a "NICREW ClassicLED Aquarium Light, Fish Tank Light with Extendable Brackets, White and Blue LEDs" this one is 18W.

Attached are pictures of my tank as it is right now. Like I said, the plants seem to be stunted so any suggestions are appreciated.

As for the propeller-- I stuck the pipe cleaner in there but I wasn't sure if that was okay to do so I didn't clean it thoroughly-- I can try doing that today and see if that helps any.
The tank looks great! Your plants are doing absolutely fine. You don't have anything that requires really high light so your lighting should be absolutely fine. I would just suggest to add a couple more plants when you have the money or chance. Something that grows really quick and that should definitely help with the nitrates. Yes you should definitely clean the propeller if you haven't done it since it's been set up. Most canister filters you can physically take out the propeller and clean it. You should not a big difference in flow rate the get clogged up quite easily.
 

LHanna61

The tank looks great! Your plants are doing absolutely fine. You don't have anything that requires really high light so your lighting should be absolutely fine. I would just suggest to add a couple more plants when you have the money or chance. Something that grows really quick and that should definitely help with the nitrates. Yes you should definitely clean the propeller if you haven't done it since it's been set up. Most canister filters you can physically take out the propeller and clean it. You should not a big difference in flow rate the get clogged up quite easily.
haha I'm happy you think so-- I find the plants very underwhelming
I had a 30 gallon back in the day that had LUSH plant growth so I'm chasing that standard. Is the light on the 20 considered low, medium or high? I've experienced a lot of plant death since setting the tank up but I'm probably at fault.

I will see if the propeller cleaning does anything and report back-- thanks for the help!
 

Ksway

haha I'm happy you think so-- I find the plants very underwhelming
I had a 30 gallon back in the day that had LUSH plant growth so I'm chasing that standard. Is the light on the 20 considered low, medium or high? I've experienced a lot of plant death since setting the tank up but I'm probably at fault.

I will see if the propeller cleaning does anything and report back-- thanks for the help!
Don't worry you will get there again eventually, it will just take a bit of time. I would consider it low light, Normally high light would be 1-2 watts per litre but that is kind of t5 and t8 bulbs. The new LEDs are definitely stronger so might not need as much. It just depends what you are trying to achieve with the scape, you can still have a beautiful scape with low light will just take a bit longer to mature and just stick to easy plants (tropica plant company have thier plants labelled easy medium hard it's good to check out )
 

LHanna61

Don't worry you will get there again eventually, it will just take a bit of time. I would consider it low light, Normally high light would be 1-2 watts per litre but that is kind of t5 and t8 bulbs. The new LEDs are definitely stronger so might not need as much. It just depends what you are trying to achieve with the scape, you can still have a beautiful scape with low light will just take a bit longer to mature and just stick to easy plants (tropica plant company have thier plants labelled easy medium hard it's good to check out )
oh interesting-- that's the most simple way it has ever been explained to me-- I was getting to invested in the Kevlins and Lumens.

I have this light, "hygger Full Spectrum Aquarium Light with Aluminum Alloy Shell Extendable Brackets, White Blue Red LEDs, External Controller, for Freshwater Fish Tank" stretched over two of my 10 gallons-- it's a 25W light. Maybe I should swap that with the 20 G light? Since the 20 G has CO2 on it, I was hoping to get some red growth. Do you think this light will achieve that?
 

Ksway

oh interesting-- that's the most simple way it has ever been explained to me-- I was getting to invested in the Kevlins and Lumens.

I have this light, "hygger Full Spectrum Aquarium Light with Aluminum Alloy Shell Extendable Brackets, White Blue Red LEDs, External Controller, for Freshwater Fish Tank" stretched over two of my 10 gallons-- it's a 25W light. Maybe I should swap that with the 20 G light? Since the 20 G has CO2 on it, I was hoping to get some red growth. Do you think this light will achieve that?
Yes the lumens and Kelvin's are much more scientific than how I explained lol. Yes I think that would be a good idea, the stronger light on the bigger tank should definitely add more light and provide quicker growth and help the pink and reds come out.
 

leftswerve

"hygger Full Spectrum Aquarium Light with Aluminum Alloy Shell Extendable Brackets, White Blue Red LEDs, External Controller, for Freshwater Fish Tank" stretched over two of my 10 gallons-- it's a 25W light. Maybe I should swap that with the 20 G light? Since the 20 G has CO2 on it, I was hoping to get some red growth. Do you think this light will achieve that?
be careful, between high nitrates and that light, you could be dealing with an algae issue. You just have to keep an eye out for it.
 

LHanna61

Yes the lumens and Kelvin's are much more scientific than how I explained lol. Yes I think that would be a good idea, the stronger light on the bigger tank should definitely add more light and provide quicker growth and help the pink and reds come out.
That was my original intension when I got the better light, I just haven't gotten around to swapping them because the light currently on the 20 G is fastened to a shelving unit.
I'm going to do that.
I'll be careful of algae growth-- the 10 gallon that has this light currently has a log fully covered in green hair algae because of the stronger light but I really like it so I never did anything about it -- just looks like a giant marimo log haha-- it's time to redo that tank though so it works out.

FOR ANYONE GOING THROUGH THIS AND WANTS TO KNOW MY RESULTS:
On Thursday night I added a brand new sponge filter IN ADDITION to the canister filter, I checked the Nitrates at Thursday night and on Friday morning there was unsurprisingly no change (40-80 ppm -- deep red), I took the canister apart and everything looked pretty clean (annoyingly clean) but I restructured my trays so that I only have bio media in the first one and the coarse sponge with a filter floss pad on top, squeezed out the sponges, cleaned the propeller and any other visible gunk in that area. I cleaned the tubes out two weeks ago and that was a lot of work with very little gunk removed so I'm not doing that again. I did a 40% water change on Wednesday so I just topped off with pure RO water when setting the filter back up.
NOTE: This is a Cascade 1000 canister filter that I am talking about in this particular instance. The recommend tray structure from what I've found on the internet is to have the top tray with floss at the top layer and a corse sponge as the bottom layer. Then for the second (bottom tray) they sell it prefilled with activated charcoal but I have filled this tray with as many Aquaneat Bio Balls as I can fit with at the addition of some smaller clay bio balls.

I'll check Nitrates tomorrow morning and note any changes and I'll update when I notice it drop -- this makes me feel like a scientist so let me have it hahah
 

FishDin

canisters are usually referred to as "nitrate factories."

you might try cleaning the canister filter pads every week and see it that makes a difference. all that poop trapped inside for several weeks continues to generate nitrogenous wastes resulting in higher nitrates.

this is from a Tidal 110 hob after 1 week, imagine after 4 weeks or longer:


full?d=1569957187.jpg
I've seen that "nitrate factory" reference before, but that's not my experience. I clean my canister filters 2-3 times a year. My tanks are stocked on the heavy side. Nitrates have never been a problem (they are at 20ppm or below prior to weekly water change). I have a few low tech slow growing plants like anubius, java fern and buce in one tank and no plants in the other.

I'm not saying that it can't happen. Many people say it does. I also know that some people run their canisters until the the flow starts to be reduced before they clean them.
 

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