Why are my nitrates high - suddenly ??

[Sunny]

Ok so I changed all the bulbs in my light fixture and the tank has never looked better. All parameters are OK except that my nitrates are around 30PPM.
It is confusing since I have not changed the food schedule, or anything else except changing the bulbs.

I did a water change and nitrates went down but very next day it was up again at 30PPM. I will do a larger WC soon but was wondering what is going on?

All fish and corals (mostly SPS) are doing well. The lighting is T5.

The only thing I did after the light bulb changes was add a few SPS frags. That is about it.

Any clues?

 

[magic]

Did you stir-up the substrate or move any lr? Have you added any burrowing fish? How old is the test kit?

Bob

 

[Sunny]

No stirring of sand. Yes, moved a few rocks around. The test kit is good. I have salifert, red sea and API. They all are in sync for once ;D

 

[Sunny]

Any more theories?

 

[panmanmatt]

Have you tested your newly made saltwater or your source water? There have been issues in the past with some salts containing nitrates.

 

[Sunny]

Yes I just did. I have 45 gallon ready to go. I use Tropic Marin Pro and the nitrates in the newly (24 hrs) mixed saltwater are almost 0 PPM.

 

[panmanmatt]

With nitrates of 30ppm doing a 50% water change is only going to bring them down to 15ppm as long has you have zero nitrates in the new water. Any trace of nitrates in the new water and the drop will be even less.

If you started with 30ppm and did a 10% water change your trates are only going to drop to 27ppm. Most test kits won't even be able to tell that difference. They will only drop by the percentage of water you are changing.

 

[MadReefer]

Mine were at 40ppm and now about 25ppm. My 1/4 inch sand bed was just filthy; I siphon up the sand now during water changes. My cleanup crew is not doing a good job or just don't have enough.

 

[Sunny]

When you siphon the sand would it not deplete? I mean would you not suck the sand with water?

 

[MadReefer]

Yes, you will get some of the sand. I think it's a small price to pay as you can replece it slowly with new clean sand. I may just siphon out all the sand and go bare bottom.

 

[reeferwanabe]

I'm starting to think I might remove my sand also madman. only thing is I'd have to take the rockwork out too to remove eggcrate thats under the sand. then mabe cut pieces of it to place under the rocks only

 

[ken6217]

Take out the sand or thoroughly gravel syphon it and your nitrates will drop like a rock.
Ken