65 Gallon Tank Nitrate still at 20 ppm after 50 % water change

Hello,

I can t reduce the nitrate in my aquarium less than 20 ppm, even after 50 % water change (vaccum gravel), moreover, it took less than 24 hours to get the gravel dirty again and my external canister get dirty in less than a week

I feed my fish twice a week only, small quantity only (they have plants to eat otherwise)

I got 2 platty, 6 molly and a lot of fry

My old 20 gallon aquarium wasnt getting that dirty that fast, if im not changing some water every 2 days, i feel like fungus or other craps could pop in my tank

Water flow of my canister 1200 l per hours, inflow/outflow dymax lily pipe stainless 16/22cm
3 layer (1 mechanical media, 2 bio media)

Any idea what could be done to keep the aquarium clean and reduce the nitrate ?

Water parameters

0 amonia
0 nitrite
20ppm nitrate
7,5PH
Temperature at 80

 

20ppm nitrate isn’t that high. I personally wouldn’t go chasing after 0ppm but more live plants would help, and check your tap water to see what that reads at. If there’s nitrate in that, you could be adding to the nitrate level each time you do a water change.

 

Agree, check the tap. If there are nitrates in the tap you can't get below the concentration in it.

 

I wanted a level at 5 or 10, i though 20 was a bit high (i read somewhere dissease, bacteria... could rise at this level)

I was thinking changing my substrate with a sand one, to get ride of all the load going trough those gravel (those a gravel stone dymax, bigger than standard gravel), could help ?

Pics of my substrate



Also my inflow outflow is not positioned optimaly, lily pipe should be next to each other, but because of the size of my tank + the install, i did put them opposite site of each corner, making a dead spot regarding the flow, anyway to fix this ?

 

I wanted a level at 5 or 10, i though 20 was a bit high (i read somewhere dissease, bacteria... could rise at this level)

Not really. It depends on the fishes requirements. Some have to be kept below 20mg/l of Nitrate. It only becomes immanently dangerous at 50mg/l, which in most countries is the legal limit in tapwater.

I was thinking changing my substrate with a sand one, to get ride of all the load going trough those gravel (those a gravel stone dymax, bigger than standard gravel), could help ?

While Your reasoning doesn't really make sense (beneficial bacteria are in the substrate and the produce nitrate, which is the normal end product of the cycle), I am very much for replacing this eye-cancer inducing plastic coated colour gravel with sand.

Also my inflow outflow is not positioned optimaly, lily pipe should be next to each other, but because of the size of my tank + the install, i did put them opposite site of each corner, making a dead spot regarding the flow, anyway to fix this ?

I would put in and outflow on opposite sites depending on the type of flow I aim for. You will have to try because decorations can redirect the flow aswell. "Dead" spots are usually not a problem and rarely really occur. You are probably only referring to a spot where detritus accumulates. This is actually great, makes maintenance easier.

 

Macz thank you for your reply well detailed, i was not notified by email regarding your answer(sorry for late reply)

While Your reasoning doesn't really make sense (beneficial bacteria are in the substrate and the produce nitrate, which is the normal end product of the cycle), I am very much for replacing this eye-cancer inducing plastic coated colour grave

My bad, my choice of words can be confusing so i will try again :

I want to change from those gravel to sand as, the sand will keep all dirt at the top, unlike gravel where it can go anywhere in between till the bottom, making hard to see and keep the aquarium clean

I m not worried about the BB as most of them are probably inside my canister (3 layer of filtration, which have ceramic ring, housing ball for BB, matrix seachem + sponge...) i actually did remove the all the gravel l
ast saturday (part of the full cleaning)

I think the problem is now solved, last saturday was the 6 hours brown out that happen every year in my building (general electric system checking/maintenance), i decided to take advantage of it to fully clean mh aquarium, including canister, hose, inflow / outlow pipe, aquarium glass).

All my media filter have been cleaning with aquarium water and make sure they stay wet

Im not sure what it was and how this happen, but some sort of brown algae have growth inside the hose (in/out), reducing the water flow, and was constantly reappering inside the gravel (every 24 hours, vaccum will grab a lot)

My in/out lily pipe are installed the right way

 

I want to change from those gravel to sand as, the sand will keep all dirt at the top, unlike gravel where it can go anywhere in between till the bottom, making hard to see and keep the aquarium clean

Allright then.

I m not worried about the BB as most of them are probably inside my canister (3 layer of filtration, which have ceramic ring, housing ball for BB, matrix seachem + sponge...) i actually did remove the all the gravel last saturday (part of the full cleaning)

I think the problem is now solved, last saturday was the 6 hours brown out that happen every year in my building (general electric system checking/maintenance), i decided to take advantage of it to fully clean mh aquarium, including canister, hose, inflow / outlow pipe, aquarium glass).

All my media filter have been cleaning with aquarium water and make sure they stay wet

So you changed substrate and cleaned the filter in one go? Please do yourself a favour and monitor all Nitrogen compounds now for a week. You removed a whole lot of bacteria that way.

Im not sure what it was and how this happen, but some sort of brown algae have growth inside the hose (in/out), reducing the water flow, and was constantly reappering inside the gravel (every 24 hours, vaccum will grab a lot)

That's not Algae but bacteria colonies. If they build up in the hoses so much they impact the flow this means your system is biologically definitely out of whack. If your tank has not gone through an ammonia or nitrite spike within the next two weeks skip the weekly waterchange for 2-3 weeks (monitor the readings in thet time!). Usually when you go back to schedule the problem should have cleared up.

My in/out lily pipe are installed the right way

There is no absolute right or wrong, always depends on application in the individual tank.

 

Mate macZ thanks for your reply, i was about making a new post regarding the bacteria build up in my hose tube. I will use and do every bit of information you are giving me instead of trying to guess/do what i can found on the web.

That's not Algae but bacteria colonies. If they build up in the hoses so much they impact the flow this means your system is biologically definitely out of whack. If your tank has not gone through an ammonia or nitrite spike within the next two weeks skip the weekly waterchange for 2-3 weeks (monitor the readings in thet time!). Usually when you go back to schedule the problem should have cleared up.

I'm not sure what you are saying but "out of whack" since english isnt my mothertong, but i'm guessing doesnt work properly

I will monitor the amonia / nitrite level on a daily basis for 2 week and do water change only if ammonia and/or nitrite are detected (otherwise no water change), except those indications, anything I should do to, maybe reoganise the media filter in the canister, replacing one media filter by another...

Actual layer :

First layer : wool sponge
Second layer : about 500g of matrix seachem
Last Layer : mix of ceramic ring / ceramic ball

There is no absolute right or wrong

Side by side isn t the right (or best) way to install the lily pipe ? ( water going out turning all around vs 3/4 ?) I made a quick drawing to make myself clear




Again thanks for your help

 

Yes, out of whack means severely out of balance.

So you have 1 layer mechanical filtration and two layers biological. No chemical. Well done.

The position of the in- and outflow is in both cases feasable. But: You are mistaken that if positioned at opposite ends the water doesn't circulate. The circulation occurs always when using a lily pipe. It's not like the end that sucks the water out stops the circulation if positioned opposite to the filter outflow. If you push on one end and pull on the other it makes for a current that's a bit stronger and more consistent.

 

Can you find floating water lettuce where you are? Seems to have worked very well for me in removing nitrates, and less problematic to remove than duckweed.

 

So you have 1 layer mechanical filtration and two layers biological. No chemical. Well done

I hesitate to replace one of the bio logical layer (as i have 2) by a chemical one (actived carbon seem to be a common one), because the information found on Google are "contentious"

From the "A must" to "Avoid at all cost", its seem nobody agree on...

So until i decided to play safe with 2 bio, till i got more info which you surely can provide the noobz ... do use any chemical one ? Which one would you recommand ?

Thinking of the bacteria build up, I had it on my previous filtration system (spray bar) but it wasnt as fast and agressive... except from fish poop and dead leaf, too much led light could be a factor ?

Can you find floating water lettuce where you are? Seems to have worked very well for me in removing nitrates, and less problematic to remove than duckweed.

Sound something I should try ! This lettuce should move with the flow or should stay in one place at the surface ? (The later one could be a bit ticky)

 

I thought it was obvious I would not recommend chemical filtration.

Activated carbon is useful to remove meds after a treatment. That's pretty much all I use it for. 72 hours at best.
Chemical filtration interferes with a lot of processes in an aquarium we wouldn't want to have disturbed.

 

Alright, i will not disturb the main tank for a while and keep monitoring the parameters, if everything is good, stability should improve by itselft

Started my QT/hospital tank but this, is for another thread

 

I hesitate to replace one of the bio logical layer (as i have 2) by a chemical one (actived carbon seem to be a common one), because the information found on Google are "contentious"

From the "A must" to "Avoid at all cost", its seem nobody agree on...

So until i decided to play safe with 2 bio, till i got more info which you surely can provide the noobz ... do use any chemical one ? Which one would you recommand ?

Thinking of the bacteria build up, I had it on my previous filtration system (spray bar) but it wasnt as fast and agressive... except from fish poop and dead leaf, too much led light could be a factor ?



Sound something I should try ! This lettuce should move with the flow or should stay in one place at the surface ? (The later one could be a bit ticky)

If the flow is strong, there are ways to fashion floating barriers around floating plants to keep them in place (should be able to find diy info online about this).

 

My plants are in the opposite side of the outflow so no problem but I keep ur advise in mind thanks !

 

I thought it was obvious I would not recommend chemical filtration.

Activated carbon is useful to remove meds after a treatment. That's pretty much all I use it for. 72 hours at best.
Chemical filtration interferes with a lot of processes in an aquarium we wouldn't want to have disturbed.

Hmm. Never really heard of chemical filters messing with processes, but I’m still kinda new to the hobby I guess. I use a sponge, activated carbon, and a layer of biological media. How does the chemical filter mess with aquarium processes? (Btw i just used the stuff that came with my aquaclear HOB filter)

 

Activated carbon does it help keep algae at bay | Water Supplements Forum | 513781

Look here for example. The stuff doesn't filter selectively, so good things are taken out too and you have to regularly replace it costing you money at no avantage at all. It has special uses but those are not longterm uses.

 

Well, mac, i guess u was right about the out of wack regarding the filtration system.

While I did add 6 neon tetra and 2 guppie, following your advise, I didnt do any water change or make change in the aquarium environment :

Bacteria build up started again in the tube's, decreasing the water flowing slowly... I would have waited a week more to see if a water change could have fix this problem but, when i woke up yesterday morning, the canister started to leak water, drop by drop, while it hasn't move an inch since my last cleaning around november 15...

Maybe I didn't do the maintenance right (with the manual in chiness only, hard to be sure), or the quality of the brand is just crappy, in any case, I will write this to help folks about to waste any bucks :

Don't buy any Periha canister filter, or anything from them

I decided to fix those problem once and for all by buying a seachem tidal 75, which is amazingly simple to install and maintain (can't say yet about his efficienty, but I'm confident). I used exclusively media filter from the canister into to tidal to keep the bacteria alive.

I did a 50 % water change and replace the purple / blue stone gravel substrate at the same time

24 hours later, 0 % ammonia or nitrite in the reading, will keep an eye for any abnormal behavior for the next few days

To bring some positivity and an ending on this thread, all the fish are fine and show no symptom of sickness or stress but brough a bunch of fry

 

While I did add 6 neon tetra and 2 guppie, following your advise,

That was not my advise. And I only said not to change water. You were very much allowed to clean the hoses regardless.

But all that aside, glad it ultimately still worked out for you.