Nitrates after a water change

[marc4]

This is something that happened early on, but i want to make sure not to repeat it.
When I was first cycling (fishless), I had no ammonia, no nitrites, but the nitrates were sky high. I did a very large water change, but when I tested the water the next day, the nitrates were still 180 ppm.

My tank has now cycled. has no ammonia, no nitrites but high nitrates. I had planned on ordering fish as soon as I decided what to get, do a large water change the day I ordered so when the fish arrived the next day, they would be going into a tank that either had almost no nitrates. Because such high nitrates right after a water change last time, I'm concerned that it will happen again and the fish will come, needing to go into the tank, and die because of the nitrates.

Does anyone know why the nitrates were so high right after a large water change? I took out about three quarters of the water when that happened and I don't want it to happen again.

Thanks,
marc4

[Slaphppy7]

Have you tested your tap water for trAtes?

You should wait 24 hours after a WC to test your tank water, when suing the API test kit.

[marc4]

Sorry about the lag time. No, I haven't tested the water for nitrates. I think I also need a new API master kit. What the heck do you do if you have a ton of nitrates in the tap? Granted there were other things going on at the time, but as I remember, the nitrates were close to 180 after the water change. This aquarium hobby is really an all in all out isn't it?

marc4

[Rocksor]

Use a nitrate resin to remove the water from the tap. You would need a 44 gallon brute trashcan to prepare the water. Another option is to have a heavily planted tank (no fish) for the first few months or however long it takes to have the plants bring the nitrates in the tank to less than 10ppm, and then significantly understock the tank.

[BluewaterBoof]

The options Rocksor provided are good, and like Slap said it is important to test your tap.

The API kit maxes out at 160ppm. Is that the kit you are currently using? Just wondering because you said you had 180ppm, which is above the highest reading on that kit's chart.

First order of business is to test your tap, as Slap stated. It is very possible that your nitrates during the fishless cycle climbed into 400+ppm, and even a large water change with nitrate-free water didn't knock it down all the way. It's all speculation until you test your tap, though. That should be the first thing you do.

[marc4]

Not having the chart in front of me when I wrote the post, it was overdone. I just knew it had been the highest on the chart.

I tested the tap water this morning, and there are no nitrates in it. That got rid of one source. The plants in my tank are soft plastic. When I started thinking about setting a tank up, I had wanted live plants, but after reading up on them, I really didn't want to get into the care of the plants on top of trying to deal with the fish and water issues. Right now things are fairly stable. No nitrites, no ammonia and I'm adding ammonia with nothing else in it but purified water (made for aquariums ammonia), and getting nitrates. I'll try a large water change and see if I get the same results on the nitrates afterwards. If I still get nitrates, then I'll look further. Thanks.

marc4

[angelcraze2]

Make sure you are testing nitrates correctly. You really have to shake the crap out of the bottle#2 and test tube before waiting 5 mins to read results. If there's no nitrates in your tap water, I can only guess that if the nitrates were very very high, you must have missed your time to water change. If you do a few large WCs in a row or daily, it should bring your nitrates down and stay where you want them to be with continued WCs when necessary.

If you remove 50% water, (and your tap water contains no nitrates) than your total ppm will be reduced 50%.

So a 50% WC should bring your nitrates down to 80ppm from 160ppm. Do another 50% WC right after and it will be reduced to 40ppm. It doesn't matter how much water you change out, the majority of your nitrifying bacteria will columnize in your filter media, tank walls, decorations.

I would get the nitrates back to 10ppm with WCs and go from there, continuing your WCs when ppm climbs over 10ppm. See how it goes, then your ready for fish instead of adding ammonia every 48 hours.

[BluewaterBoof]

The problem with the test is that it only goes up to 160ppm on the chart. OP could easily bee hundreds of ppms higher but the kit won't tell him that. That would explain why it is still reading 160ppm after water change.

Honestly, with no livestock to worry about, I would personally just drain the tank as low as possible and do a complete water change. Just make sure you put dechlorinator in the new water before running it through the filter(s).

[angelcraze2]

I just used 50% to explain the ratio. But yes, you can remove as much water as you want without livestock since nitrifying bacteria does not reside there.

Thanks for pointing that out :)

[marc4]

I try to follow the manual that comes with the test to the letter. I find those colors in the red zone difficult to read. The 160 I can usually tell because it looks like blood whereas the others are slightly lighter. After giving the tank three hours post water change, I redid the nitrates, and can put it somewhere between the 40 and 80 close to right between.

Until I find a fish that can live well in the water we have, should I keep changing the water? If so, how much and how often?

marc4