Always High Nitrates

I started up my 20 gal freshwater tank in September 2017. I let it cycle for a few weeks and tested my water before adding fish. All was going great until I had a sudden ammonia spike that killed 4-5 of my fish. I managed to get my ammonia levels back down to normal when I installed a new filter. Since the ammonia spike though, I have had constantly high nitrate levels. I've done multiple water changes,put Purigen in with my filter, feed the fish only what they can eat in 30 seconds or so and only give them Omega One food. I have also added a Hornwart plant to the tank and my nitrates are still consistently high. What else can I do?! I'd love to be able to restock my tank again someday and get my healthy water back.

 

What fish are in the tank now? What are your actual readings?

 

Did you add any source of ammonia before you added fish? Otherwise, you didn't cycle your tank before you added fish, it was just sitting there. When you added your fish (ammonia source), the ammonia spike is totally normal. I have the same questions as david1978

 

What fish are in the tank now? What are your actual readings?

I have 5 tetras, one goirami, and 2 algae eaters. My nitrates are usually around 20 I'm using the API freshwater master test kit, no strips.

And no, no ammonia source was added prior to adding fish. My local fish store (small and locally owned) just said to let it run for a few weeks, test the water, and slowly add fish. I added 3-4 at a time every couple weeks, as long as my levels were normal.

 

I have 5 tetras, one gourami, and 2 algae eaters. My nitrates are usually around 20 I'm using the API freshwater master test kit, no strips.

And no, no ammonia source was added prior to adding fish. My local fish store (small and locally owned) just said to let it run for a few weeks, test the water, and slowly add fish. I added 3-4 at a time every couple weeks, as long as my levels were normal.

My ammonia and nitrites are completely normal

 

ok you did see an ammonia spike since you didn't cycle your tank you just let it run with water so no beneficial bacteria was built up since their was no source of ammonia to feed it. Under 20 nitrates is what most shoot for so its not high. If I may ask what kind of algae eater?

 

ok you did see an ammonia spike since you didn't cycle your tank you just let it run with water so no beneficial bacteria was built up since their was no source of ammonia to feed it. Under 20 nitrates is what most shoot for so its not high. If I may ask what kind of algae eater?

Well that is definitely good to know, thank you! The fish store I usually work with acted like 20 was awful and would eventually harm my fish. They had me convinced that zero is the only safe reading. I have 2 otocinclus catfish.

 

It would help to show a picture of your tank so we could see what kind of substrate, and how much, and what other stuff you've got + its arrangement.

What kind of Maintenance do you do on your substrate?

 

I agree 20ppm nitrates is good.

I do water changes when mine get to 40ppm.

You’ll never have 0 unless all of your fish get constipated at the same time, or you don’t feed them

 

It would help to show a picture of your tank so we could see what kind of substrate, and how much, and what other stuff you've got + its arrangement.

What kind of Maintenance do you do on your substrate?

I typically do a 20% water change at least once a month (my goal is every 3 weeks, but I don't always succeed at that) and I vacuum thru my gravel with my water change. I never fully clean it out bc I was told that could mess with my cycle. Is that true? I'm rather new to the fish world.

 

H

I agree 20ppm nitrates is good.

I do water changes when mine get to 40ppm.

You’ll never have 0 unless all of your fish get constipated at the same time, or you don’t feed them

How often do you do water changes? I was told a couple different things by the store I typically use. I've been told biweekly and monthly. My goal is every 3 weeks, but it's usually once a month.

 

You were told right, unless there’s some extreme reason, never change 100% of the water and gravel. If you have some kind of tank emergency and have to change 100% of the water, just make sure the water that you replace is the same temperature as the tank was. I usually shoot for once every two weeks. When I kept Discus I did it about every 3 days, but they’re extremely sensitive to water quality. The fish you have don’t need it that much. I’d say once every 1-2 weeks is a good amount. Once a month is a little long in my opinion, even if your water is testing fine you still replace a lot of things when you change the water.

 

I typically do a 20% water change at least once a month (my goal is every 3 weeks, but I don't always succeed at that) and I vacuum thru my gravel with my water change. I never fully clean it out bc I was told that could mess with my cycle. Is that true? I'm rather new to the fish world.

Monitor your nitrates via your test kit. When they get above 20, do your water change. It may be every 3 days, weekly, bi-weekly or monthly. Let your test results determine.

I have tanks that can go 10 days and not go above 40, another tank that needs a water change every 4 days.

 

Monitor your nitrates via your test kit. When they get above 20, do your water change. It may be every 3 days, weekly, bi-weekly or monthly. Let your test results determine.

I have tanks that can go 10 days and not go above 40, another tank that needs a water change every 4 days.

Water changes shouldn’t be based just on your nitrate levels.

 

Water changes shouldn’t be based just on your nitrate levels.

What should they be based on?

 

Well besides nitrates, things you can’t/don’t test for. Phosphate buildup, General unbroken down waste, water clarity, disease prevention, mineral replenishment, algae prevention, ect. I’ve seen sick fish heal completely by just doing frequent water changes, it’s really good for your fish.

 

It would help to show a picture of your tank so we could see what kind of substrate, and how much, and what other stuff you've got + its arrangement.

What kind of Maintenance do you do on your substrate?

 

Well besides nitrates, things you can’t/don’t test for. Phosphate buildup, General unbroken down waste, water clarity, disease prevention, mineral replenishment, algae prevention, ect. I’ve seen sick fish heal completely by just doing frequent water changes, it’s really good for your fish.

So the difference between 7 days or 10 days wouldn’t matter if nitrates were low? For phosphate buildup,it would take a significant amount of time unless you had high phosphates in your water source? The other things you mentioned would also take significant time, more than 10 days?

I thought I was missing something.

I agree that frequent water changes are the best preventive medicine.

 

I'm doing water 25% changes, minimum of 2 times a week. That would be the minimum for any tank I have which is cycled and has a full-normal bio load.

If I am understocked, I can get away with a lot more time between changes.

I normally tend to do more and smaller changes. I have big filters and I don't clean them very often or very well.

But I will not hesitate to do a huge water change if I think the fish need it. I smell my tanks every day. If something stinky pops up out of the substrate, I will know that it's time for a serious change without even touching the test tubes.

In fact I would advise anybody setting up a new aquarium to smell it frequently and every time they test the water.

Compare what you see with what you smell, and eventually you will train yourself to avoid a lot of chemistry practice by using your nose.

 

Hayle Kluesner

Thanks for the photograph.
I don't see anything scary.

I don't really think you have high nitrates at all, considering how infrequently you change the water.

 

Well that is definitely good to know, thank you! The fish store I usually work with acted like 20 was awful and would eventually harm my fish. They had me convinced that zero is the only safe reading. I have 2 otocinclus catfish.

If your nitrates were at zero, then you could have/could cause a cycle crash. Your bacteria need to be able to eat something! 20 to 40 ppm is a good range to aI'm for, with the ideal being the low end of that scale. At 40ppm, then you need to be doing partial water changes to keep it from spiking higher.

I've had spikes up to 80ppm and the shrimp were just fine. My nerite snail sure didn't like it, though, but he recovered.