The Planted Tank Forum banner

i can't get nitrates down

2K views 25 replies 11 participants last post by  AbbeysDad 
#1 ·
i have an established for 3 yrs pretty heavily planted tank with anubias, val, wisteria and some bacopa but my nitrates stay way up. my ammonia and nitrites are fine. i have a penn plax cascade canister on this 120 gal. it's the cascade w 5 trays (can't remember the capacity i think 150 gallon). i do monthly 30% water changes. i only feed once a day with beefheart and they eat it all still wanting more. i stopped using flourish or advance several months ago and even tried nitrazorb but still have nitrates. this is my discus tank so i have to be careful... help!
the pics are water parameters done today, a couple different angles to get better light reading in the pic. .
 

Attachments

See less See more
2
#2 ·
How old is your test kit? Have you tried a different kit?

Are you shaking the kit as directed in the instructions?

That said, if your kit is fine and another kit gives you the same reading, you'll obviously want to change your water more frequently than once per month.

Even without nitrate issues, you'd want to do more frequent water changes. That's just good practice as a hobbyist - especially with something like discus.
 
#4 ·
it's a new kit, less than 6 months old. i used to do wc at 2 wk intervals but my plants started looking wilty and the discus started losing color so i went to monthly. i do clean the canister every 2wks. but just rinsing the media to keep the biologicals, i do change the carbon each time. i only have 6 discus, 2 clown loaches, 3 twigs, a featherfin and a gold spot pleco so it shouldnt be overstocked.
i'll try a new test kit when i go out to lfs again.
 

Attachments

#6 ·
The only reason that would likely be happening is if you aren't matching parameters - which you should be with something as sensitive as discus. And if plants are suffering, they're not receiving proper nutrients. There are several ways to resolve that without impacting your fish.

Far be it for me to tell anyone what to do but only changing water once per month is likely 99% of the problem. Frequent water changes are important. There's no way that tank is planted heavily enough to allow for such breaks between changes. Not even bi-weekly changes. I'd be doing it on a weekly basis. Nitrate compounds and continues to increase on a daily basis.

I've never seen a discus keeper go that long between changes. At least not that I can immediately recall.

my plants started looking wilty and the discus started losing color
 
#5 ·
i do test the new water periodically. for my discus i use spring water tapped from up on the mtn. it comes out like an artisian spring straight out of the ground w a ph of 6.0 naturally. there are no livestock around so the water is always pretty pristine.
 
#7 ·
ok, i'll go back to weekly and see. i'll increase the plants too. i thought it looked pretty crowded but i guess it's not.
the marlboros and blue are just over 2 yrs old and seem to be doing ok. any suggestion on additional plants? and is there such a thing as too many plants (lol!)?
 
#8 ·
I agree it's the 30% monthly changes. Lets say you start with 0 nitrate from your spring and you build up 40ppm over the month. Then you change 30%. That brings your nitrates back down to 28ppm. Over the next month you build up another 40ppm, so that's 68ppm total. This time your 30% brings it down to 47ppm. By the end of three months you are up to 87ppm and your water change only brings it down to 60ppm. It will keep gradually climbing a little each month and a few more months (or three years) down the line it gets really high.

Now imagine a 50% change. You start at zero, build up to 40ppm, change 50%, you'll even out around 35ppm max over time as you are always cutting it in half.

Doing 30% every other week will add up to roughly 50% a month too, if you prefer more smaller changes.

To reset you want to do a few changes in a row e.g. twice a week for the next two weeks do 30%. That will bring it right back down so you are starting from scratch. It's quite likely other things in your water have built up too so I'd do a series of not huge changes, rather than a massive 80% change. You can make them even smaller and do more if you want to make it an even more gradual change.

For plants, you want fast growing stems or floating plants and you may need to add ferts too, they might be missing one of the nutrients they need so can't make use of the nitrates effectively.
 
#9 ·
Ok so I have good news and some moderate bad news for you.

The good news is that your filter has a strong and thriving culture of bacteria. The moderate bad news here is "Beefheart." Don't get me wrong, you shouldn't stop feeding it to your discus but at the same time you have to realize that Beefheart (and the other meats a beefheart blend contains) are more protein rich and in short, result in more nitrates at the end of the nitrogen cycle.

I'm using both a fish mix and beefheart mix and going from a planted tank, that was fed flake food, to beefheart was a "shock" in terms of the levels of nitrates it created. My advice? Two water changes a week and employ some faster growing, nitrate consuming plants. If you chose to add a fertilizer to boost growth use one that doesn't have macros like nitrate.

Lastly, and I say this with some trepidation considering your tank is beautiful, I'd remove the large flat/grey stones. At a glance, they look like they're creating a lot of crevices which could trap uneaten food and also be a breeding ground for bacteria and dead spots. That said, I am no expert. So please feel free to disregard any advice that doesn't suit your vision for your aquarium.

Rolla
 
#10 ·
You can see that the discus are being adversely affected by the water change schedule as well.
Their growth has been affected by the high nitrate level by being moderately to severally stunted in growth. You can see this in the shape of the head, eye to body ratio, and thin bodies (girth of body and head).

As sub-adults, discus should have a water changing schedule of at -minimum- 2 x 50% weekly. 100% turnover rate. That is minimum. I do this still, with my adult discus- but, i want many discus to be of maximum health.
Discus are a lot of work- that's why so few people keep them.

Edit: 2 years old? I just saw that. They are not sub-adults. They are adults. Well, the ability to change the effects of high nitrates on growth has sailed. At minimum- 50% water change weekly or nitrate level never higher than 15 ppm.
 
#11 ·
To echo others, 30% monthly is just not enough!...and with the exception of the wisteria, your plants are not fast growing plants that would convert nutrients (aka pollution) into plant tissue quickly enough.
In addition to checking your source water for ammonia and nitrates, I think you'd find that 50% weekly is more what you need to keep your fresh water fresh.
 
#12 ·
hmm, ok. the discus were 1.5 -2 inches when i got them so they have grown. the nitrates are just a within the last year issue and i've been trying all kinds of stuff during that time.
kind of disheartening to learn all this when i thought i was doing pretty good. but i'll cut the beefheart and replace with discus hand flakes. i'll do every other day water changes to try to get the nitrates down. fingers crossed... geez, now i feel like a failure tho.
 
#13 ·
Well you have kept things alive and ticking over this time period. Ecosystems are complicated so I wouldn't feel too bad. You could easily have more then one issue here so trying to diagnose it is pretty complicated.

Speaking of which, have you ever had your water tested in a lab to find out what kinds of minerals and metals might be in it? If you have a lot of heavy metals in your water you could have a situation where the metals are poisoning your plants but not enough to kill your fish. That would explain why your plants were looking bad with more frequent water changes. Those metals can be removed by yet more plants, but as others pointed out the slow growers would do especially bad in that situation. Something else to test /shrug.
 
#14 ·
i sent my spring tapped water to a lab once along with a sample of some R/O a friend gave me, just to do a comparison. my water came back with better results than the other. it's been a while and i don't remember the specific mineral breakdown but it was pretty spot on for tannic mountain spring water. my land is in the mtn and joins national forest so there are barely any pollutant issues. i may have a friend of mine who works in the hospital lab do a sample for curiosity now.
i just feel so bad that my fish may have been suffering and i didn't even realize it.
 
#18 ·
I'm having the same issues, but I think i'm making progress. I was doing 10% water changes twice a week, but I didn't think gravel cleaning was desirable with an undergravel filter system. Now I do a 10% and a gravel cleaning (with ends up being like 30%.) I've added "Matrix" to my canister filter and am adding Frogbit. I don't know how much of a difference this will make, but I think I'm on a good track, maybe there's a piece to my formula you may want to try. Of course, the Frogbit will be my 1st plant in my tank, so, with what you describe, gravel cleaning isn't an issue.
 
#19 ·
Also have to wonder how clean your gravel is. With that size substrate it’s probably a huge detritus trap. Try using a turkey baster and blast into it around tank and see what comes floating up. Think you’ll be shocked at amount of waste just setting there.

Also by stopping dosing your plants are in total deficiency shutdown, they’re not going to be uptaking much of anything in way of nitrates or phosphate with out the dozen or so other elements plants need to grow. By necrosis I see in plant leaves I’d actually say their actually contributing to your nitrate build up instead of helping.

Also why is your light so blue? Looks like a saltwater light and a very weak one at that. If you want plants to grow you need to at least give them the minimum amount they need and proper spectrum. Floating plants would really be a better option for you, they can really suck down nitrates since they can get all co2 and light they want at surface. But even those will fail and rot away if you don’t give them proper spectrum/amount of light and do light dosing to make sure there is no nutrient deficiency.

All the other advice you’ve been given is solid, but those few other things seem worth mentioning as well because they do effect how the whole tank performs as whole.
 
#20 ·
i stopped using flourish or advance several months ago and even tried nitrazorb but still have nitrates. this is my discus tank so i have to be careful... help!
I think you might have a big problem with your fertilizers. Seachem Advance Only has are Potassium Chloride, Potassium Phosphate, Sodium Phosphate, Calcium Chloride, Magnesium Chloride, That is only 5 of the 14 nutrients plants need to grow, Most of the ingredients in Advance are organic compounds which a healthy plant can make on its own.

Seachem comprehensive assumes that your water has many of the nutrients plants need and just adds a little to supplement tap water. I used this in my tank for some time and I could only get intermittent growth of my plants at best. I was using RO water which has basically no nutrients in it. If your spring water is very soft you might have the same problem I did.

With few nutrients in your water your plants are probably not growing very fast and as a result are not consuming the nitrogen the fish are producing. I am guessing your fish are producing a enough NPK and combine that with insufficient water changes you are going to have high nitrates and probably high phosphate and potassium. Do you know what your GH ( general hardness) and PH of your water is? GH is a measure of calcium and magnesium levels in your water. Calcium, magnesium, are the other macro nutrients that your plants need there won't be enough in any fertilzer. The PH level may impact you sellection of fertilizer.

Basically means you need a good micro fertilizer. Many on this site use CSM+B as micro fertilizer but it works best in acidic water with a PH less than 7, Preferably 6.5 or less. IF your PH is high it might not work for you. The other option I can think of right now is to use Nilocg.com Thrive. This is much like flourish but with higher micro levels. It does however have nitrogen and phosphate but with more larger water changes and a better fertilizer your tank may end up with overall lower nitrogen levels. but with a good fertilizer. But check your GH try keeping it at 2 degrees. Hopefully a GH of 2 degrees will supply enough calcium and magnesium without making the water too hard for your fish.
I don't have any experience with discuss but I think. Need be use a GH booster like Nilocg.com GH booster to increase your GH to 2. that with a better fertilizer might help your tank.

Note I have no experience with Discuss so I don't know how sensitivity they are to fertilizer.
 
#22 · (Edited)
Hi @DaveKS , side note on this thread, I'm getting Frogbit in my mail today (fingers crossed, it's hot today) and I have good surface movement on one side of my tank and minimal on the other side. So, I took some spare filter plastic parts (basically tubing with holes running thru it) and tied it to the center support molding that divides the surface (allowing two 24" covers which I'm not using) to keep the Frogbit on the calm side until they grow together. I'm worried that the side with all the agitation might drown the plants by sending them underwater. Does this sound like a good plan? I uploaded a pic. Of course, I'll have to "let them free" during a partial water change, but I'm guessing I can coral them back.
 
#24 ·
i have done water changes out the wazoo and tested tonight with a new kit and the result was all yellow! no orange or red at all! yea! i really appreciate all the input and will definitely keep all this in mind. i also went to my lfs and scooped up tons of sprite and anachris. he had a pretty good sized african onion plant, which i've never seen before so i picked that up. it has about 15 stems and is about 24inches...really neat looking plant! seriously i must of got 20 or more sprite plants and a whole bunch of anachris so, i'll keep up the water changes more frequently, cut the beefheart frequency and see if i can keep the plants going. thanks so much for all the advice!
 
#26 ·
I just re-read this and realized that you're using activated carbon in the filter. You really don't want to use carbon in a planted tank as it will strip the nutrients your plants need to grow!

Anyway, glad you got the nitrates down!
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top