Nitrates still high after cycle

[Rfields987]

I’m cycling a bare bottom 200g tank since 6 July. Ammonia is zero or just about. Nitrates and Nitrites are +50 and +1. I’ve just changed 30% of the water and surprised to see the Nitrates and Nitrites remaining close to the same. Rock was all dry, bio bricks in the sump. 16oz of Fritzime 900 early July. Any idea what my problem is?

 

[LeftyReefer]

Any fish yet?

Your nitrates should have gone down by about a third when you did a 30% water change. You can keep doing water changes to lower the nitrates. The larger the water change, the more it will lower your nitrates.... As long as your replacement water doesn't contain new nitrates.

Are you using RODI water?

Typically you will need to find a way to export nitrates from your tank. The amount of nitrates will depend on your bioload and nitrates added via feedings.

 

[Pistondog]

doing a 20% water change lowers nitrate by 20%.
So look into longer term solutions like fuge or algae reactor.

 

[Dan_P]

I’m cycling a bare bottom 200g tank since 6 July. Ammonia is zero or just about. Nitrates and Nitrites are +50 and +1. I’ve just changed 30% of the water and surprised to see the Nitrates and Nitrites remaining close to the same. Rock was all dry, bio bricks in the sump. 16oz of Fritzime 900 early July. Any idea what my problem is?

Nitrite interferes with nitrate measurement. How are you correcting the nitrate measurement for nitrite?

 

[Rfields987]

I’m not just using Red Sea test kit and reading values

 

[Rfields987]

Any fish yet?

Your nitrates should have gone down by about a third when you did a 30% water change. You can keep doing water changes to lower the nitrates. The larger the water change, the more it will lower your nitrates.... As long as your replacement water doesn't contain new nitrates.

Are you using RODI water?

Typically you will need to find a way to export nitrates from your tank. The amount of nitrates will depend on your bioload and nitrates added via feedings.

Any fish yet?

Your nitrates should have gone down by about a third when you did a 30% water change. You can keep doing water changes to lower the nitrates. The larger the water change, the more it will lower your nitrates.... As long as your replacement water doesn't contain new nitrates.

Are you using RODI water?

Typically you will need to find a way to export nitrates from your tank. The amount of nitrates will depend on your bioload and nitrates added via feedings.

No fish yet, just ordered fuge components recently

 

[Rfields987]

Yes using RO/DI water

 

[splitting_lanes]

No fish yet, just ordered fuge components recently

Add fish before you get the fuge running or you’ll wind up with a 0 nitrate problem.

 

[swiss1939]

Your results were probably above the highest on the test so doing your water change didn't seem to affect the results cause you are still within range of the highest bracket for that test. Do another 30% change and see what you get. Or dilute your test in half and see if it goes down to 25 nitrates. That will tell you if more water changes will help.

You were probably at 100 nitrates originally

 

[Pistondog]

Your results were probably above the highest on the test so doing your water change didn't seem to affect the results cause you are still within range of the highest bracket for that test. Do another 30% change and see what you get. Or dilute your test in half and see if it goes down to 25 nitrates. That will tell you if more water changes will help

For clarity, dilute the test with what?
Rodi or makeup saltwater?⁹

 

[LeftyReefer]

Agree with swiss1939. Since no fish yet, a large water change won't hurt anything. Do a large water change to reduce the nitrates down to a manageable level, then add your fish and fuge and then see where you are at.

I think you're off to a good start regardless... This is just a small minor issue. Nothing to worry about at this point.

 

[swiss1939]

For clarity, dilute the test with what?
Rodi or makeup saltwater?⁹

Dilute with RODI. 50/50 with tank water.

 

[swiss1939]

When I did my cycle, I had to go so far as 25% tank water to RODI just to get an accurate result for my nitrates. Red Sea Test only goes to 20 or 25 I believe, and my actual NO3 was over 50ppm. I accidentally dosed too much ammonia at the start of cycle and had to do like 60% water change at the end of cycle to bring my nitrates down into an acceptable range.

 

[Tiki Reef Joshua]

I would do a near 100% water change, wait a day and test everything. Don't keep nickel and diming the water changes... just do it all. The bacteria should be on your rocks...

 

[Tiki Reef Joshua]

Also... depending on your testing kit, IF YOU HAVE ANY NITRITE, your nitrates will read inaccurate high.