Purigen in week 6 of cycle

[Davar]

I have a ocean free nano 5 (96l) tank. Been cycling for 6 weeks and 3 days now. Ammonia, nitrite and nitrate all sat at 0 for first 2 weeks until I added 1dead shrimp (from deli) to water, then ammonia spiked hight for 5 days then dropped to zero as nitrites and nitrate maxed out. 3.5 weeks later ammonia still zero, nitrite still 5.0+ and nitrate still 160+. Last few days done 1 x 10% water change and 1 x 33% water change 1 day apart. Nitrites and nitrates still maxed out. Just placed bag of purigen into filter canister... Am I doing the right thing? What else could I do?.. Further info pH is and always has been a healthy 8.2, sg is 1.024 and temp 26.5 (nicely in the green zone). Really wanting to get my first fish soon, what else can I do to lower my maxed out nitrites and nitrates?

 

[glb]

Is your ammonia 0? If so, I think you’re far enough along to do a water change. I used pure ammonia to cycle, and the idea was that after adding it, if the ammonia is back to zero in 24 hrs, the cycle is almost done. The ammonia being zero is the key. What test kit are you using for the nitrites and nitrates?

 

[lavoisier]

Your tank is making progress. You just need to be patient as your nitrifying bacteria population grows to the point of 0 nitrites.

 

[glb]

Your tank is making progress. You just need to be patient as your nitrifying bacteria population grows to the point of 0 nitrites.

Agreed.

 

[xiholdtruex]

I have a ocean free nano 5 (96l) tank. Been cycling for 6 weeks and 3 days now. Ammonia, nitrite and nitrate all sat at 0 for first 2 weeks until I added 1dead shrimp (from deli) to water, then ammonia spiked hight for 5 days then dropped to zero as nitrites and nitrate maxed out. 3.5 weeks later ammonia still zero, nitrite still 5.0+ and nitrate still 160+. Last few days done 1 x 10% water change and 1 x 33% water change 1 day apart. Nitrites and nitrates still maxed out. Just placed bag of purigen into filter canister... Am I doing the right thing? What else could I do?.. Further info pH is and always has been a healthy 8.2, sg is 1.024 and temp 26.5 (nicely in the green zone). Really wanting to get my first fish soon, what else can I do to lower my maxed out nitrites and nitrates?

Had this same issue cycling my tank, I cycled with pure ammonia. did you use live or dry rock? did you use live or dry sand?
this can all effect this. I would change 75% of the water and give it 24 hours and retest if not 100% of the water. you want to see if you sand and rock are also leaching nutrients.

 

[Dkeller_nc]

Actually, with the nitrate so high, there's a potential that it's interfering with an accurate reading on your nitrite kit. Since your tank is only 96 liters (25 gallons for us Yanks), I would suggest that you do a 15 gallon water change and retest the water. If it's less than 50 ppm, then you're good, and you can add your first (hardy) fish. If it's not, then wait a day or two and do another 15 gallon change. That will almost certainly drop your nitrate under 50 ppm, and your nitrite will likely read zero, in which case it's safe to add a fish or two.

BTW - add your livestock slowly. It can be a mistake to add a full load of fish all at once to a newly cycled tank.

 

[Randy Holmes-Farley]

FWIW, the nitrate is likely not that high. Nitrite causes huge interference in many nitrate kits, and 1 ppm nitrite will read as 100 ppm nitrate with some kits. Ignore nitrate until nitrite is gone.

 

[Dkeller_nc]

FWIW, the nitrate is likely not that high. Nitrite causes huge interference in many nitrate kits, and 1 ppm nitrite will read as 100 ppm nitrate with some kits. Ignore nitrate until nitrite is gone.

Yep, that's definitely a potential issue. One observation I've made over the years is that while the initial ammonia to nitrite conversion can be slow to get started when one starts with a bare tank and dry rock, once it does, the final step of nitrite to nitrate conversion goes very quickly.

And back in the day, a lot of folks didn't typically test for the whole nitrification cycle - they simply monitored the ammonia level until it went to zero, did a water change, and added a few hardy fish. While I'm not sure that I would always recommend that procedure, I've actually never lost any fish once the ammonia level went to zero and a 50% water change was performed.

 

[Davar]

Is your ammonia 0? If so, I think you’re far enough along to do a water change. I used pure ammonia to cycle, and the idea was that after adding it, if the ammonia is back to zero in 24 hrs, the cycle is almost done. The ammonia being zero is the key. What test kit are you using for the nitrites and nitrates?

Yes my ammonia is zero, I did have ammonia spike to 8ppm at week 3 (after adding dead shrimp because at this stage nothing had budged from zero) and then it dropped to zero after about a week and nitrites and nitrates maxed out (where they haven't budged for 3 weeks now). I added another dead shrimp a week ago for 12 hours which caused ammonia to rise to 2.0ppm for about a day before returning to zero, so ammonia seems good, it is quickly forced back to zero. However nitrites and nitrates continue to stay at 5.ppm(NO2) and 160ppm(NO3) even after a 33% water change. I setup tank with AF rock (aquaforest) and dry sand. at around week 4 i added bottle of dr tims bacteria, now i am adding a capful of seachem stability every day for 5 days in a row now. I am using API saltwater master kit (pH, ammonia, nitrite and nitrate) pH is 8.2, ammonia is 0. Thank you for your replies

 

[Dkeller_nc]

You really don't need to continue to add bottled bacteria to your tank - your biofilter is already established.

If it were my tank, I'd change 50% of the water (12.5 gallons), and add a hardy fish. For a tank of that size, an ocellaris clown, a 6-line wrasse or other smallish fish would be appropriate.