Jump to content

High nitrates in tap water after starting new setup

Recommended Posts

Hi all. I was wanting anyone's opinion on a curve ball that got thrown my way when starting up my aquarium. The main problem here is when I first started preparing my tank and my plan of action, the nitrates in my tap water ranged from 0-10. All of a sudden in the last 2 weeks, they are now 20-40!! Here's my specs:

50 gallon Landen tank
Fluval stratum substrate with a layer of Eco Complete in the middle (Bentley Pascoe recommendation)
Fluval 3.0 plant light on 3 inch risers ( 70% on whites, 65% red, 5% blue). On for 7 hours a day with a 1 hour ramp up and 1 hour ramp down
Oase Biomaster Thermo 850 canister filter attached to glass lily pipes
10 lb. CO2 canister hooked to a 24 inch NilocG reactor
Easy Green fert dosing (Doing 1 ml per day for now. Was planning on upping dosing once tank/plants really established. See below for when tank was started, etc.)
Doing 50%-80% water changes weekly (see note below on why so high)
Tap water parameters - NH3 - 2, NO3 - 20-40, pH - 7.6, GH - 15, KH - 9
Using Seachem Prime for water changes.
Current tank parameters today (3/23) - NH3 - 0, NO2 - 0, NO3 - 80, pH (before lights on) 7.0 (I get a pH drop of 1 during the day), GH 12, KH 2

Plants in the tank:
Val Americana
Ludwigia super red
Myrio mattogrossense
Ozelet green sword
Christmas moss
Buce x 3 different types
Crypto petchii
Monte Carlo
AR mini
Salivinia minima floating plants

10 guppies (with at least 4 babies that I can see!!)
Wanting to get more after initial phase of getting the tank started

So I basically did a dark start method of starting up this tank back on 1/27. Cycle completed 2/27 and on 3/2 I planted all the plants above. Since 3/2, I've been doing what I have typed above (I've recently doubled my Easy Green dosing as plants have become established). Got fish last week on 3/17. Note that all of my plants (with the exception of a lot of melt from my swords plants) have excellent growth. No complaints there!! However, my nitrate level in my tank is consistently 80 or higher. I've been trying to stay at 50% water changes, however since my nitrate level is so high, I've done around 80% water changes a couple times. Couldn't figure out why so this week I tested my tap water and the nitrate level is 20-40. I was about ready to up my Easy Green dosing per instructions (put enough Easy Green in to attain 50 ppm of nitrate - then you can get a feel for how weekly dosing will go). But I can't do that any more with such high nitrate levels. As of right now, I only have a few very small areas of green string algae on my moss, but that's it. I worry that keeping nitrate so high will cause an algae outbreak plus be detrimental to my fish. Plus, I am afraid to add any more Easy Green since it is a nitrogen source as well.

Sorry this is so long, but here's the question. I can't change what's in my tap water and I'm not going the RO route. What would everyone suggest I do fertilizer wise? I love using Easy Green (I use it in my son's low tech tank as well). However, I might have to use something that doesn't introduce as much or any nitrogen. Any thoughts? Thanks in advance!!


Link to comment
Share on other sites

My tap is similar with high nitrates. I don’t use fertilizer because it’s also farm runoff and could possibly be bottled as liquid fertilizer. We don’t drink it. At one point I found this that has no nitrate. 
I also use tons of emergent plants to keep nitrates under control. 







  • Like 1
Link to comment
Share on other sites

I would stop using EG, and find a fertilizer just containing P, K and Micros. This way you will be able to maintain NO3 from water changes and any bioload. Hang on to the EG incase they change the water on you. Dry fertilizer works great for these situations, but APT should have a low NO3 all in one solution. 

@Guppysnail method works well too.

NilocG might have a low/no NO3 option also.


  • Like 1
Link to comment
Share on other sites

I don't have a nitrates in tap water issue, however, if I were to have one... I would set up an aging setup with good lighting and emergent plants (pothos, bamboo, etc) and floaters like water lettuce.  I'm already aging and pre-heating water anyway.  So it wouldn't be a huge deal.  My experience is that it's tough to keep nitrates in my tankswith those plants in the tanks.  I would probably also put some sort of a grid suspended midway so that when the water drains down, it catches most of the plants and keeps them away from the pump.

Link to comment
Share on other sites

Lot of bare area going on, I personally would look to add more fast growing plants. Especially ones that are nitrate hogs, hornwort would be my primary plant id include. The other option mentioned above, floating plants, frogbit, water lettuce, and if you are not opposed to it the dreaded duckweed.

Brightwell also has a fertilizer called floruinMulti which I have mixed reviews over. It's big selling point is its  nitrate and phosphate free. But beware, its highly concentrated. I believe their Recommended daily dosing amount is something crazy low like 1ml for 40g!

Another thing you might be up against is if im not mistaken Fluval Stratum is an active substrate, so you might not be battling high nitrates in your tap water, but also fighting high(er) nitrates from your substrate. In any case good luck! Im not sure if this was helpful, but just wanted to add my half a cent! 🤣

Edited by JoeQ
  • Like 1
Link to comment
Share on other sites

my tap water has high nitrates, 20ish ppm. we are in the process of asking our water company to do something about it because the legal limit of nitrates in drinking water here is 10ppm. but for now I am using store bought spring water. works fine for me because I only have one smallish tank. but do make sure that you are not drinking your tap water with high nitrates in it because it can cause health problems. buying spring water or getting an r/o filter at least for your consumption would probably be good. 😄

Link to comment
Share on other sites

Thanks to everyone so far for your quick responses. This forum is really great!!! I do like the idea of trying a fertilizer with no nitrogen in it. That APT Zero might be a good choice for me. Seems to have similar other ingredients / ratios as Easy Green. May have to also supplement with phos as well. I will hold on to the Easy Green since I like it so much in case my tap water quality changes. I feel like I have a good mix of fast growing nutrient users. My tank seems sparsely planted since it's just been planted. Plus I used a lot of tissue culture plants. But I have myrio and floating plants that have gone nuts since I planted. All other ones doing well too. I might have to contact my water company and see what the deal is. We do drink our water in the house but it's run through a filter in the fridge. But good tip there about really trying not to drink it from the tap. I might also benefit from a new nitrate test kit?? Mine is a little over a year old.

Anyway, if anyone has any more good ideas (all of them here have been so helpful), please let me know. But I may be leaning towards the APT Zero for a period of time until nitrates go back down in the tap.

Thanks again everyone!!! I'm sure I'll have plenty of more questions in the near future.


  • Like 1
Link to comment
Share on other sites

One thing I also didn't mention is this time of year municipalitys flush the water lines (its a really smart move to use extra conditioner) the nitrate spike in your tap might be from chemicals used during the process. 

Edited by JoeQ
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Create New...