On cycling and nitrates shows 100ppm?

[mooputingtong]

i started cycling my tank this sunday and dosed first ammonia on tuesday.
After showing low ammonia and nitrates I dosed again on thursday.
Today I tested again and ammonia shows about .25 ppm and nitrates is really dark purple which means could be over 100ppm or less.
Is it normal to have such a low ammonia but high nitrates?
I will test again tomorrow and if nitrates are still high i will do my first 20% water change and keep monitoring.
My goal is to hit 10ppm nitrates then i will add livestock.

 

[Spare time]

Keep in mind that if you have nitrite, some nitrate tests will read very very high. However, it is normal to have a higher ppm of nitrate than you had for ppm of ammonia. It is always a good idea to do a very big water change after the cycle.

 

[mooputingtong]

Keep in mind that if you have nitrite, some nitrate tests will read very very high. However, it is normal to have a higher ppm of nitrate than you had for ppm of ammonia. It is always a good idea to do a very big water change after the cycle.

will 20% be enough or should i do like 50%?

 

[Funston07]

+1 on the nitrites. If you have nitrite present it will totally throw off your nitrate reading

 

[Spare time]

will 20% be enough or should i do like 50%?

I would do as big of one as you can get. It is a bad idea to start off with dirty water as you are setting yourself up for the dreaded algae phase.


Alternitevly, you could use something like dr tims waste away (or similar products) do lower the nitrates and phosphates. This would add some microbial diversity into the tank which is always good.

 

[ScubaFish802]

As Spare time said above you will have to do a water change at the end to lower your nitrates back down before you can add fish

 

[saltyhog]

There are separate tests available for nitrite and nitrate.

Once your ammonia gets to zero again, do the water change and I'm sure your nitrates will come down slowly over the next few weeks. Be patient about increasing bioload, if you do it slowly and not over do it you shouldn't have a big problem with nitrates going forward.

 

[flampton]

Remember, each PPM of ammonia added gives close to 3x the nitrite and more than 3x the nitrate. Specifically - 1 ppm of ammonia when converted by the nitrifying bacteria in the filter, results in 2.7 ppm of nitrite, which in turn produces 3.6 ppm of nitrate.
So it makes sense you would be putting in ammonia and then seeing much more nitrates at the other end of the cycle
As Spare time said above you will have to do a water change at the end to lower your nitrates back down before you can add fish

How can you get differing ppm of compounds that are in 1:1:1 ratio together. Where is the extra nitrogen coming from?
NH3-NO2-NO3

 

[ScubaFish802]

How can you get differing ppm of compounds that are in 1:1:1 ratio together. Where is the extra nitrogen coming from?
NH3-NO2-NO3

http://www.reefcentral.com/forums/showthread.php?t=864197, maybe I am incorrect or misled . . but that has been my understanding

 

[flampton]

Checked that thread... Yeah unfortunately you were misled. Not sure why but they were comparing molar masses. Mass has nothing to do with concentration. So if you have 1ppm ammonia you have 1ppm nitrogen. Thus as it goes through the cycle the nitrogen has to remain balanced thus you get the ratio 1:1:1

 

[KennethN]

How can you get differing ppm of compounds that are in 1:1:1 ratio together. Where is the extra nitrogen coming from?
NH3-NO2-NO3

It is because you are actually not measuring it in ppm as in number of molecules per million, you are measuring it in mg/l (milligrams per liter).

 

[flampton]

It is because you are actually not measuring it in ppm as in number of molecules per million, you are measuring it in mg/l (milligrams per liter).

If it's in mg/l then it's not ppm. It can't be both. All the test kits I have used measure in ppm.

 

[ScubaFish802]

I’m more confused now lol. Isn’t 1 PPM = 1 mg/l?

 

[flampton]

I’m more confused now lol. Isn’t 1 PPM = 1 mg/l?

Okay I think I see the confusion now. 1ppm is equal to 1mg/l but ONLY for ammonia. It just happens to be a coincidence as both ammonia and water have the molar mass of 18. Nitrite and nitrate have different molar masses and thus ppm does not equal mg/l.

 

[KennethN]

If it's in mg/l then it's not ppm. It can't be both. All the test kits I have used measure in ppm.

I’m more confused now lol. Isn’t 1 PPM = 1 mg/l?

It is confusing, I agree.
1 liter of water = 1 kg = 1 000 000 mg. So 1 mg in 1 liter = 1 ppm.
But, the unit ppm might make you think that you are counting the number of NH3/NO2/NO3-molecules per 1 million molecules, but you are not. It is the weight of the specific molecule in 1 liter of water that is measured, and then since the molecueles have different weights you will get different ppm:s

 

[flampton]

It is confusing, I agree.
1 liter of water = 1 kg = 1 000 000 mg. So 1 mg in 1 liter = 1 ppm.
But, the unit ppm might make you think that you are counting the number of NH3/NO2/NO3-molecules per 1 million molecules, but you are not. It is the weight of the specific molecule in 1 liter of water that is measured, and then since the molecueles have different weights you will get different ppm:s

I see...hmm well if this is true it's a extremely unscientific way to do things. Coming from the science world we would refer this as cringeworthy. Haha

Okay maybe one day the aquarium world will use real units like molarity.

Everyone I apologise if I confused you. Apparently science hasnt touched this hobby yet.