Water Parameter Issues-Elevated Nitrates

[mbecker6294]

I have a well established 35Gal tank that I've converted over to live plants. Fish and plants seem to be happy, but wanted to start tracking water parameters.  Have 3 inches of inert pea sized river gravel, and have been using EG and root tabs. Water parameters with Tetra easy strips are reading:

Nitrate    Nitrite    GH    Total Chlorine    KH    PH 20              0.5       150         0                  40    7.8 80              0          150         0                120    6.8 The top row of numbers is my tap water, 2nd row from tank.  I've done two 25% water changes since 4 days ago and Nitrates still at 80ppm.  Have stopped dosing with EG until the nitrates are consumed.. Any other water parameters above I should be concerned with? I'm nervous about the tap water having 20ppm on the nitrates and have thought about installing RO/DI.  Thoughts?? I clean the HOB filter media sponges and water polishing cloth as to not build up organic waste. Dechlorinate with API Proper PH 7.0 on weekly 25% water changes

[Biotope Biologist]

Do you have any other media in the HOB filter? if you only have mechanical filtration then your bacterial filtration will never fully establish. You can add a prefilter sponge to the intake of the HOB and convert all media in the filter to porous ceramics or plastics, whatever you can get your hands on. This will allow your bacteria colony to establish itself instead of being disrupted during every water change.

The other suggestion is since you have a tank with high depth low surface area either invest in an undergravel filter and porous media or a small fan to get the lower water column to move.

 

Remember nitrate is 4x denser than water so good flow keeps it from "settling"

Edited March 23, 2021 by Biotope Biologist
they don't teach grammar in science

[mbecker6294]

HOB has 3 sponges, two are newer that I was establishing for setting up a new micro tank, 50 micron cloth, Chemipure easy green, and fluval biomax that has been running for over 12 years. when I clean the filter, I only rinse the media in dechlorinated water, so I would think there should be plenty of bacterial filtration.  Don't have any ammonia test strips, didn't think necessary to have for an established tank, but wondering if there could be ammonia in my tap water?  Only thing I can think of that would convert to nitrate so quickly.  Has anyone else come across this?

[Koi]

My tap water is around 40 ppm nitrate and .5 ppm nitrite, so pretty similar to yours. I don't think you necessarily need an RODI unit If nitrates is the only reason for getting it but theres nothing wrong if you want to get it.

80 ppm nitrate isn't ideal but it isn't as critical as ammonia or nitrite. If you want to lower it down a considerable amount quickly, 50% water changes or above probably would resolve that in one water change. But if you would rather do smaller water changes, you could probably bring it down in a couple of weeks (depending how often you are changing out the water)

Also I just wanted to add that completely cutting off easy green might not help with reducing your nitrates. I know it sounds counterintuitive to add fertilizer to you tank to reduce nitrates but you need the all the other nutrients from easy green for the plants to be able to consume nitrates. Try considering adding a fast growing plant like hornwort , water sprite/wisteria, elodea, or some kind of floating plant.

Edited March 23, 2021 by Koi

[Biotope Biologist]

Ammonia in tap water is exceedingly rare unless your source is a well. Any disturbance of filter media is enough to "dislodge" bacteria. I would just have one micron cloth for inflow and convert the rest of the filter media to your biomax rings. 

 

Again having sufficient flow at the bottom of your tank will also help with mechanical filtration and aeration. If the waste cannot get to your filter where it is converted than it will just sit in the water column.

 

I do not know enough about chemipure easy green to comment on it. The website suggests it is only activated carbon and resin which I fail to see how that helps plants. But if it also contains micronutrients such as cobalt and potassium then I don't see any harm in running it for plant food.

 

[Koi]

1 hour ago, Biotope Biologist said:

Remember nitrate is 4x denser than water so good flow keeps it from "settling"

I never knew that, thats interesting. So does that mean when testing it is better to pull water from the bottom? Or is this only something that occurs if there is no water circulation?

[Biotope Biologist]

This is only an issue with no flow. Nitrate is soluble in water so it tends not to matter where your test source is. Also it's closer to 3.44x I just rounded up because I am not in Organic Chemistry anymore so I like to break rules. 

[mbecker6294]

Hey guys, I think I may have figured out the issue. The tank is many years established and has plenty of biological filtration. Nitrites running at zero with a moderate bio load. Something has to be a nitrate pump. The fluval biomax has been running a long long time, like 10-15 years. Breaking down ammonia and nitrite like a champ, but do you think the pores have collected enough detritus and food over the years that even though I rinse them off in tank water from time to time, can the media be acting as a nitrate pump?

[mbecker6294]

Changed out half of the old bio max with new material and did a 25% water change. Retested today and nitrates with 30-40ppm. Will change out the rest of the bio max in 2 weeks and see if it eliminates the nitrate issue

[Mmiller2001]

It's your gravel, large gravel like that is a nitrate factory. Also, root tabs just leach right out of the substrate.

[Patrick_G]

It’s been running for years with low Nitrate levels then you changed to a planted tank and added root tabs and liquid fertilizer, both full of Nitrogen. I think that’s the most likely suspect for the elevated Nitrate levels.