Nitrogen levels cycling with dry rock

[paperdesk]

Background. I'm starting up a new 90gal tank, and 40gal sump. I have been curing the dry base rock at normal reef temp/salinity etc. for about a month. I never saw any phosphates at all, so I figured the rock was safe and put it into the aquarium, added ammonia, and let it cycle. After ammonia and nitrites got to zero I dosed ammonia again. Ammonia and Nitrites were back at zero in less than two days. However, a week later my nitrates are still pegged at 100 (Salifert). I've been doing a lot of reading, but can't seem to find out what I should do now. Should I:

1. Do a 100% water change?
2. Let it go, and the nitrates will eventually come down?
3. Something else?

I'm not in a hurry, just trying to figure out what the next step should be. Is it ok to leave the nitrates so high, and if so, for how long? I don't want to encourage unnecessary algae blooms etc.

All that's in the tank is the base rock and one tiny piece of liverock pulled from another tank. I haven't even seen any algae in the tank other than what came on that little piece of liverock.

Ted

[scott3569]

Hey Ted,

I never cured my dry rock,however that doesn't really matter..after you add amoinia the amonia and Nitrites should come back down with in 24 hrs..48 might be acceptable, but I have always read and seen 24..as far as you nitrates go, you could do a 25% water change and see what that does..your nitrates will take a long time to come down on there own if they ever do at all..thats why most people do whater changes, not to just get rid of nitrates, but to also replinish nutrients that are in the salt mix for a good reef.

[thegrun]

If you don't have any livestock in the tank I would make a 100% water change. It seems likely the rock is leaching nitrates, but you may want to double check the nitrate readings with another test kit to be sure the test kit you have isn't bad, a reading of 100 is very high.

[paperdesk]

So when I read about nitrate turning to nitrogen gas, is that something that only happens in small scale? How long does it take? I'm not rushing and am happy to wait it out if that is best, but have no livestock yet, and can easily do a full water change. I will double check my test kit today but I think it's OK.

[GMay]

NO3 to nitrogen gas is a very slow anaerobic process and is not efficient enough in a new tank to reduce NO3. The only way to reduce NO3 in a tank is through water changes.

[inetmug]

I put some rock into a tank after an acid wash, I am glad I did. Unfortunately, I did not do a bleaching first, and my guess is I got some kaka deep in the rock that the acid did not get. I an getting high phosphates, zero ammonia, but about .25 nitrite.

I have zero smell, so I am not exactly sure why the phosphates are testing out high.

What is your phosphate reading with the high nitrates?

[paperdesk]

OK water change it is then! I never had any phosphate reading. Clean rock or bad test kit I guess!

[inetmug]

OK water change it is then! I never had any phosphate reading. Clean rock or bad test kit I guess!

So screaming nitrates, and no phosphates. I thought they went hand in hand? Maybe Randy can chime in on this.

[Randy Holmes-Farley]

If you are cycling with ammonia (ammonia --> nitrite --> nitrate), you won't get any phosphate unless there is some other addition.

If the rock isn't releasing any, time to be happy about that, paperdesk (assuming, as you suggest, the kit is OK. :D). :)

[paperdesk]

I was able to double check that my Ammonia, Nitrite, and Nitrate tests are ok. The store didn't do Phosphate testing, so I haven't double checked that. I suppose I should just break down and get a Hanna Checker.

I did a retest on my Nitrite and found that it's not zero as I thought (read before in poor lighting) but it's at 0.2. I think I should hold off on doing a water change till that hits zero. Agree?

[Randy Holmes-Farley]

I personally wouldn't bother tracking nitrite. It is not toxic in marine systems, especially at that level. Ammonia being gone is the primary concern.

If nitrate is really 100 ppm, I'd definitely change the water, but that would assume that you somehow added a whopping amount of ammonia (several hundred ppm) unless you have begun using fish food or the rock had dead organic matter on it (which should also boost phosphate). So I am suspicious that it isn't correct.

[paperdesk]

Yes, Nitrate is really that high, double checked that with another test. I just looked at my log, and it appears that my nitrates were at 100 even before I dosed Ammonia.

I used RO not RODI water to cook the rock, and had also put in some really old vacation fish food blocks I scrounged from my supply box that I hoped would help start a cycle. They didn't seem to break down very much, so I didn't think they affected anything much, but maybe they did. I would really like to double check my Phosphate levels! Seems I could check the test kit by testing something known to be high in Phosphate. I'll look into that today. Any ideas what I could use as a known Phosphate source? I have rock phosphate . . .

[inetmug]

RO/DI in SW, or just the FW?

[paperdesk]

Inetmug, I used RO water for the SW mix when I cured or "cooked" the rock, and used RO/DI water for my DT. I didn't use FW only for anything.

[Randy Holmes-Farley]

Nitrate was above 100 ppm before adding ammonia? If that is real, there must be lots of organic matter decaying on the rock, and phosphate likely will be elevated, even if your kit detects none.

I would do a water change if you are really convinced of the nitrate (a second test doesn't "confirm" it since such tests vary wildly, but it might possibly be that high if the rock was dirty with organics.

[toku58]

Do you run a skimmer?
I had high nitrate in my small 10 gal. The ammonia and nitrite was at 0 but the nitrate was high.
Water changes barely made a difference. I put a protien skimmer and that helped to lower the nitrates in my tank.

Not sure why? But might be worth trying?

[paperdesk]

Do you run a skimmer?
I had high nitrate in my small 10 gal. The ammonia and nitrite was at 0 but the nitrate was high.
Water changes barely made a difference. I put a protien skimmer and that helped to lower the nitrates in my tank.

Not sure why? But might be worth trying?

I do have a good skimmer, but right now I have no livestock so there's really nothing to skim.

Nitrate was above 100 ppm before adding ammonia? If that is real, there must be lots of organic matter decaying on the rock, and phosphate likely will be elevated, even if your kit detects none.

I would do a water change if you are really convinced of the nitrate (a second test doesn't "confirm" it since such tests vary wildly, but it might possibly be that high if the rock was dirty with organics.

I'm not 100% sure the nitrates were that high before adding the ammonia, but that is what my log says. I don't specifically remember testing for Nitrates and it seems I would remember it if it were that high, but maybe I was more concerned about the Phosphates at that point.

I did, however, check my Salifert nitrate test kit with a test strip at a pet store in town and it came back as 75. Unfortunately, they don't test for Phosphates.

I'm going to research how to check if a phosphate test kit is working.

[BoyNextDoor]

phosphates are from silicates. Nitrates are from decaying matter in your tank (uneaten food, decaying live rocks, dead fish/snails/corals. some say they do come hand in hand but i beg to disagree because if they do, you should have a diatom bloom by now.

it is normal to have a high nitrate in this stage because you are just starting the end of your cycle. this stage will really test your patience because almost all parameters will be crazy for the next few days.

as long as your ammonia and nitrite read 0 (make sure it is 0), then you can do water change. if you have any livestock, do a 50% water change and run it for a couple of days and check the Nitrate parameters. if they do went up again, do another 50% water change but honestly, Nitrates will eventually come down on its own. you only do this is you have livestock. I suggest getting macroalgae first like chaeto to consume your nitrates.

also check your phosphate because nitrates won't come down easily if you have a very high phosphate.

[paperdesk]

I personally wouldn't bother tracking nitrite. It is not toxic in marine systems, especially at that level. Ammonia being gone is the primary concern.

I got to thinking about this more. I'm not actually concerned about the Nitrite level being toxic, but that it would appear to indicate that my tank is not fully cycled. It's not normal for an established and cycled tank to show nitrite is it?

[Randy Holmes-Farley]

phosphates are from silicates.

Is that a typo?

[Randy Holmes-Farley]

also check your phosphate because nitrates won't come down easily if you have a very high phosphate.

Why do you think that?

[Randy Holmes-Farley]

Having some nitrite does indicate cycling isn't complete, but the level you have may be testing error. Regardless, a water change now is an OK plan to get rid of that huge load of nitrate, and I do not think that amount of nitrite is worth waiting before you add your first hardy organisms and stress the cycle a bit. :)

[paperdesk]

phosphates are from silicates. Nitrates are from decaying matter in your tank (uneaten food, decaying live rocks, dead fish/snails/corals. some say they do come hand in hand but i beg to disagree because if they do, you should have a diatom bloom by now.

it is normal to have a high nitrate in this stage because you are just starting the end of your cycle. this stage will really test your patience because almost all parameters will be crazy for the next few days.

as long as your ammonia and nitrite read 0 (make sure it is 0), then you can do water change. if you have any livestock, do a 50% water change and run it for a couple of days and check the Nitrate parameters. if they do went up again, do another 50% water change but honestly, Nitrates will eventually come down on its own. you only do this is you have livestock. I suggest getting macroalgae first like chaeto to consume your nitrates.

also check your phosphate because nitrates won't come down easily if you have a very high phosphate.

Thank you for your comment! By the way, the Philippines is one of my favorite places! Do you SCUBA dive? I really love the diversity of life there.


Having some nitrite does indicate cycling isn't complete, but the level you have may be testing error. Regardless, a water change now is an OK plan to get rid of that huge load of nitrate, and I do not think that amount of nitrite is worth waiting before you add your first hardy organisms and stress the cycle a bit. :)

I see the wisdom of what you are saying here. I'm going to do a big water change today or tomorrow. Odd that after all this time I still have no algae, even with such high Nitrate levels, but I'm sure it WILL come!

[BoyNextDoor]

phosphates are from silicates. - its not a typo. there are several sources of phosphates and in most cases it is from the sand or the rocks in our tank.

also check your phosphate because nitrates won't come down easily if you have a very high phosphate. - based on experience this is true. even regular water change will not lower down these 2 animals.

have a good read on this http://reefkeeping.com/issues/2006-09/rhf/

[BoyNextDoor]

paperdesk - yes i was into scuba diving before but due to my hectic schedule, I settled down on a reef tank :) This country, I can proudly say, is one of the world's best spots for marine life. message me if you plan to go here. :)

[paperdesk]

I've only dived in Palawan and Negros but I know there are many amazing dive sites. I plan to be near coron this coming spring.

[Randy Holmes-Farley]

phosphates are from silicates. - its not a typo...

have a good read on this http://reefkeeping.com/issues/2006-09/rhf/

Good idea. :lol:

By the way, I wrote that article. Silicate is not in any way a source of phosphate.

The primary source of phosphate to the water column in steady state reef tank is foods. There may also be phosphate coming off of calcium carbonate sand and rock if it was exposed to very high phosphate in the past, and breaking down organic detritus in any type of sand, including silica sand, can release phosphate as well. :)