Tap water tests at 80 ppm nitrates. Now what?

We've had a 10 gallon tank with 4, and recently 6 zebra danios since mid-April. We also have three Amazon Sword plants.

I've been having trouble making sense of water quality, and to be on the safe side, started doing daily water changes of between 10% and 50%, most typically a 25% change.

The nitrates keep going up. So today finally tested our tap water:

pH: 7.2
Ammonia: 0 (looks slightly between 0 and .25, but I've learned here on fishlore that the API master kit often shows .25 ppm
Nitrite: 0
NItrate: 80 ppm or slightly higher!

So have I been messing things up with such frequent high nitrate water changes?? Before this, I was only doing partial changes once a week, and the nitrates were always around 10-20 ppm. I am dosing the tank with 1 mL (well, one thread line of cap) of Prime after every change.

One of the danios--the smallest--has been hiding more and more, and barely came our of his little faux log at all today. I'm worried I'm stressing them all with so many water changes, especially now that I see how high our nitrates are.

I haven't cleaned the filter (Fluval 20) at all yet. I've read so many different comments about when and how to change filters, that I've just procrastinated doing it at all.

Obviously new to all of this. Thank you for your patience.

{Edits for typos}

 

May I suggest to test your faucet water one more time.

If you're using the API test kit, be sure to thoroughly shake both bottles of nitrate test solutions for 30 seconds to a minute before adding the drops to the test tube.

Are you on a municipal water supply or well water?

 

Thanks for reply.

We have municipal water.

I followed the API instructions to shake Nitrate bottle #2 for thirty seconds before adding it to test tube, and then shook the test tube for a full minute before letting it sit for 5 minutes before reading.

I will do the test again anyway, just to be sure.

 

We have municipal water.

The chance of your water treatment plant being in violation is very small. They use much better tests and 80 ppm isn't toxic for fish or human infants (there's talk of raising the drinking water limit because it we didn't understand things when the limit was set decades ago).

 

My first though it that there has to be something on the market that can remove nitrates from water, but if not and the tap is actually that high, RO water might be the next step.

 

Assuming everything is correct and accurate, having three Amazon swords will essentially solve your problem for you. They'll eat up your nitrates in time, and you can continue doing water changes to help clear other things out of your water without having to worry about your nitrate situation being backwards from most other hobbyists.

If you're dealing with ≥80PPM nitrates, you'll want to make sure your don't exceed a 50% water change (especially if you have any residual nitrates) but performing small water changes (and essentially getting free fertilizer for your swords!) should keep things in check. Keep testing to see how long it takes your plants to consume that 80PPM, and time your water changes around that.

 

Plants. I would say you should call your state water authority and mention the 80ppm off your tap. It shouldnt be more than 10, but i have seen up to 30 before on mine, and it sits around 15 regularly. Anyways back to plants.
You can either set up a big tub and put plants only in it and take your water from there to fill your tank. Or put some easy growers in your tank and rely on them to filter your water more than the water changes. 1st option is foolproof, but not cheap and time/space consuming. 2nd option depends largely on stocking levels and abundance of plants and if they can overtake the waste the fish produce, so also very time consuming getting them to grow.
The other really viable option with tapwater would be looking into plenums or anoxic filtration. Cheap, but complex with a learning curve and has a minimum 6 month seeding timeframe. But it is the cheapest long term fix if done correctly.

 

My first though it that there has to be something on the market that can remove nitrates from water, but if not and the tap is actually that high, RO water might be the next step.

Unfortunately, RO isn't very good at removing chloramine (it's really the carbon stage that does it and usually not very well). So you spend all that time and money and...the chloramine that gets through is more toxic than the nitrate.

Plants. I would say you should call your state water authority and mention the 80ppm off your tap. It shouldnt be more than 10, but i have seen up to 30 before on mine, and it sits around 15 regularly.

The regulatory limit is 44.3 ppm.

 

Retested just now. I shook both bottles for 30 seconds before adding each, and shook tube for full minute, then took this pic at five minutes. Stood in brighter light and think this looks like maybe it’s between 40 and 80? Still higher than the 10 and 20 readings I had with smaller, less frequent water changes.

I think my first step will be to only do 10% changes every 12 hours for a few days, and see how that affects all the levels.

If that doesn’t help, then I’ll make my way through the other suggestions here. Thank you so much!

 

Get 1 water lettuce.
1 purigen pouch for the filter media.
1 small pothos plant,suspend the roots in the water and let the leaves hang out of the tank.
This will fix your nitrate problem

 

I’ve been looking at these levels so long now that I feel like I can’t even discern a difference between the 40 and 80 rectangles. I need to go shut my eyes for a few minutes!

 

I like the suggestions regarding adding the plants. I've got Pothos like Wrench said, it is an easy plant to have.