Tank cycle question

becks · Aug 14, 2016

It's been a very long time since I last cycled a tank and that was with my dad. I've been cycling my tank now for four weeks, I used live sand and pukani dry rock.

I started the cycle by adding a small bottle of atm colony then dosed ammonia & np pro to feed the bacteria.

My current levels are;

Ammonia 0 - dosing to 3ppm will drop down to 0 within 12 hours.

Nitrite is 1ppm and so far has not dropped to 0

Nitrates are between 75 - 100ppm
Phosphates - 0.03

All tested using salifert kits.

I need to change out the floss and remove the media bag that contains rowaphos as its connected to my sump inlet so will contain some detritus and clean the sump too.

I have a small diatom bloom. Will my nitrates drop on their own? Or will I need to add cheato/ nitrate reactor? My concern about doing a water change is if the anerobic bacteria has not built up enough they will just keep raising to high levels requiring constant large water changes.

There's no life stock in the tank.

Thanks

reeferfoxx · Aug 14, 2016

Since you didn't cure the pukani, you will have mass amounts of phosphates. I can't explain why you have such high nitrates really. Maybe because you are dosing ammonia?

Randy Holmes-Farley · Aug 14, 2016

With some kits, if you have nitrite, it shows as a lot of nitrate.

I'd just keep watching and waiting, but nitrite is not toxic (unlike in freshwater systems) so don't agonize over it.

becks · Aug 14, 2016

reeferfoxx said:
Since you didn't cure the pukani, you will have mass amounts of phosphates. I can't explain why you have such high nitrates really. Maybe because you are dosing ammonia?

I did cure my pukani rock, and I only have 0.03ppm of phosphates. Maybe it's from the ammonia?? But the ammonia is 9.5% ammonia and the rest is water,

Randy Holmes-Farley said:
With some kits, if you have nitrite, it shows as a lot of nitrate.

I'd just keep watching and waiting, but nitrite is not toxic (unlike in freshwater systems) so don't agonize over it.

Are salifert kits known to show high nitrates when nitrite is present?

Randy Holmes-Farley · Aug 14, 2016

becks said:
Are salifert kits known to show high nitrates when nitrite is present?

The last time I heard from the owner, that was the case, yes.

becks · Aug 14, 2016

Randy Holmes-Farley said:
The last time I heard from the owner, that was the case, yes.

This could be the case, because even though I have high nitrates I thought my ats would still grow algae despite very low phosphates, but nothing was able to grow. My lighting and flow is correct for the ats.

Randy Holmes-Farley · Aug 14, 2016

FWIW, many things can impact algae growth, such as shortages of elements such as iron.

Also, higher nitrate does not necessarily mean faster growth unless it is the limiting nutrient. If something else is limiting (such as phosphate, iron, etc.), then there's little to no difference, say, between 5 ppm nitrate and 200 ppm nitrate from an algae growth rate perspective.

becks · Aug 14, 2016

Ok thanks randy, I'll test nitrates again once my nitrites drop to 0 and see what I get then

Randy Holmes-Farley · Aug 14, 2016

Sounds good.

Happy Reefing

becks · Aug 16, 2016

I think i found the problem to the high nitrates, I blasted the rocks with my turkey blaster and all kinds of junk came out, so i blasted all the rocks I could then siphoned the detritus, I have some big chunks of pukani rock and there must have been alot of organic matter inside the rock that the pressure washer could not reach after bleaching the rocks...In some ways I wish I had used the carribsea life rock now.

Randy Holmes-Farley · Aug 17, 2016

That could be a cause, yes.

becks · Aug 18, 2016

The water change and syphon detritus did not seem to make a difference, hopefully it's a false reading from nitrites like you said, I'll wait for my nitrites to drop completely and test again.

TherealplexiG · Aug 19, 2016

Randy Holmes-Farley said:
With some kits, if you have nitrite, it shows as a lot of nitrate.

I'd just keep watching and waiting, but nitrite is not toxic (unlike in freshwater systems) so don't agonize over it.

In my experiences, i have had cycle stalled with very high nitrites when i used to dose ammonia at par and there was no conversion to nitrates. I found a solution later on that dosing ammonia without measurement was the culprit. But could you enlighten on the chemistry part of it, why and how does this happen?

reeferfoxx · Aug 19, 2016

TherealplexiG said:
In my experiences, i have had cycle stalled with very high nitrites when i used to dose ammonia at par and there was no conversion to nitrates. I found a solution later on that dosing ammonia without measurement was the culprit. But could you enlighten on the chemistry part of it, why and how does this happen?

When you've added enough ammonia to start the nitrogen cycle and nitrites are present. At this point the acid that is produced, will drop pH. If more ammonia is added after this point, pH(usually below 7) will drop more resulting in a stalled cycle.

If you had stopped dosing ammonia and performed a small 20-30% water change(to raise the pH), the cycle most likely would have continued.

TherealplexiG · Aug 19, 2016

reeferfoxx said:
If you had stopped dosing ammonia and performed a small 20-30% water change, the cycle most likely would have continued.

Water change was not possible at that moment (10000 ltr system), that was few years ago with commercial stocking. We used to put encapsulated bacteria (Those were used for waste water recycling, now we have various products of these sort in the market but IMO it has various drawbacks). Was just curious to know the chemistry part of it as you mentioned "ACID" and pH drop.

reeferfoxx · Aug 19, 2016

TherealplexiG said:
Water change was not possible at that moment (10000 ltr system), that was few years ago with commercial stocking. We used to put encapsulated bacteria (Those were used for waste water recycling, now we have various products of these sort in the market but IMO it has various drawbacks). Was just curious to know the chemistry part of it as you mentioned "ACID" and pH drop.

Oh wow! Thats a big tank!

Ammonium Nitrite i believe is what the "acid" is called?

TherealplexiG · Aug 19, 2016

reeferfoxx said:
Oh wow! Thats a big tank!

It was and i meant stocking tanks, small cubes but connected into a singular system.

becks · Aug 19, 2016

I just tested my alk and it came in at 6.8 dkh, should I raise my alk up by baking some baking soda?

Randy Holmes-Farley · Aug 19, 2016

TherealplexiG said:
In my experiences, i have had cycle stalled with very high nitrites when i used to dose ammonia at par and there was no conversion to nitrates. I found a solution later on that dosing ammonia without measurement was the culprit. But could you enlighten on the chemistry part of it, why and how does this happen?

You mean the testing issue?

Nitrate itself is fairly resistant to chemistry so detection choices are more limited than, say, ammonia. According to Habib (owner of Salifert), his kit (at the time anyway), converts a portion of the nitrate into nitrite as part of the chemistry of detection. Then the nitrite is detected and a multiplication factor is applied to account for the fact that only some of the nitrate is converted to nitrite and detected.

Thus, 1 nitrate counts as 1 nitrate, but 1 nitrite already in the way is multiplied up and counts as more than 1 nitrate.

This is not normally a concern since nitrite in reef aquarium is normally very low.