Question (1 Viewer)

[Darrel]

I am cycling my tank, and everything was on track till this mornings readings, which are bewildering to me.

I have watched the Ammonia spike and drop to zero, The nitrite Spike and is now down to .25ppm, and falling. But my nitrates were at about 40ppm and this morning was only 5. I did this test twice to ensure I had it right. Also the PH has been holding at about 8.0 and I am adding Kent buffer to raise it to 8.2, but this morning the PH was 7.8.
Temp is a consistant 77, and my lights are on from 5-10pm right now.
I have now livestock in the tank so I am using the light time to help control algae.

I am confused....

Please advise if you can.

 

[Darrel]

Could the Nitarte drop be because there is little to no production from Nitites, the algae is now consumming all the Nitrates?

 

[rxonco]

I'm guessing that you meant to say you "have no livestock" in the tank.
pH is going to fluctuate during the day/night cycle. The swing you're seeing isn't enough to warrant dosing anything yet. Especially seeing as how you don't have any livestock.
That being said...How long ago did you start your cycle? How much live rock do you have? Was it all "live" or was some of it dry? If so how much? Do you have a sandbed? How much? What did you start your cycle with? Fish, food, raw shrimp, etc...?
What kind of testing kit are you using. Your NO3 should not drop like that unless you did a water change or had a significant amount of macroalgae in a fuge. Even then, it shouldn't drop substatially over a short period of time like that. My guess is one of the tests were off. If the NO2 is still registering, I'd hang tight. Would still need to know answers to the above questions to see where you are in your cycle.

 

[Darrel]

I peed in the tank like you suggested....LOL.

No seriously, 125 gal tank, 80lbs live sand, 40 lbs dry sand, 50 lbs dry rock, 70 lbs live rock.

Started the cycle with just the live rock and sand, then added a small amount of shrimp.

Been cycling for almost 3 weeks, been monitoring for the last two.

I am just having a hard time figuring out why the Nitrates dropped off so drastically in 24 hours.

Using an API test kit, also had the water tested at the LFS a few days ago to have a "kit" check and verify accuracy, came up with exactly the same readings.

I did not do a water change, I was preparing to next week. I just added about 1.5 gallons for top off.

I shouldnt say there is no livestock, the liverock now has many very small feather dusters on it, I would like for them to survive, that is part of the reason I am concerned with the Ph.

 

[rxonco]

pH is still ok either way. My best guess would be that your first test of 40ppm NO3 was incorrect. If your NO2 is at 0.25, NH3 is at 0, it's highly likely that an accurate reading of your NO3 is closer to 5. I'd give it another week and you should be good to go. For the record, I actually did use urine for my startup. Just because my wife said I wouldn't. I used a shrimp too.

 

[DustinB]

No ammonia anymore is fine. NO2(Nitrite) should spike a small amount and fall. NO3(Nitrate) should fall without a heavy fish load. Your sand and rock will both convert NO3 to Nitrogen.

NO3(Nitrate) should only build up if you are not using a very porous rock or you have a heavy fish load. Macroalgae, as mentioned previously, can help to remedy that situation.

For example, my 40B has 4 small fish and about 90 corals. I run no macroalgae and I have 0 NO3. My 90g I just setup 2 months ago completed the cycle in one months with dry rock. It has no NO3 either.

The way the nitrogen cycle works is by starting with ammonia, the main pollutant from fish waste and decaying matter. Bacteria form to convert the ammonia to NO2(Nitrite). Once that happens, bacteria will form to convert NO2(Nitrite) to NO3(Nitrate). These are both aerobic bacteria, meaning they thrive in an area with access to oxygen, such as the surfaces of your rock and sand bed etc... The next type of bacteria are anaerobic bacteria. This is what forms deep in your live rock or in the lower parts of your sand bed where there is little to no oxygen, it will perform the final conversion from NO3(Nitrate) to Nitrogen where the Nitrogen will be released from the tank.

Basically what you are looking for is that you have seen both ammonia and nitrite, with both of them falling to 0 for say a week. Then you can start by adding a fish or a cleanup crew, etc... Just add very slowly as the bacterial populations will have to build up to meet the increased bioload.

 

[rxonco]

Unless you have an established DSB, you're not going to see a drop in NO3 like that within a short period of time. That's why I say your initial test was probably off. Your ammonia is 0, your nitrite is probably falling, and now your nitrate should start to climb. Essentially, your cycle is complete. Like I said, give it a few more days and you're good to start adding livestock. You could go ahead and begin to add CUC now if you want. I'd check your NH3 in a couple of days. If it's 0, head out and get that first fish you want.

 

[Darrel]

Thanks for the info. I understand the cycle, and don't plan to rush anything, adding 1 or 2 fish every other week is the plan, then once the tank has aged a bit and I am cretain everything is stable I will start with the corals.

I was just thrown for a loop with this mornings readings and wanted to stay on top of it.

Again, I thank all of you for your support. Looking forward to possible meeting a few of you this Saturday if my work schedlue alows.

 

[DustinB]

You didn't mention how long ago the test read 40ppm.