fishless cycle using ammonium hydroxide

[jaybarks]

need some help please! i have 350l tank and plan on doing a planted tropical tank. i am using eco complete substrate from carib sea, ro water with my own minerals added (up to 150 TDS) to keep phosphates in check. i have the temp at a steady 82F to speed up the bacteria growth and plenty of oxygen into the tank by two airlines and good turbulence at the surface by pointing my external filter towards the top of the water. i decided to use pure ammonia (25% strength) to cycle the tank as i thought it would be better than using fish food (again back to keeping the phosphates as low as possible to keep algae blooms to a minimum). i started the cycle about three weeks ago and till now everything seemed to be going well, i kept the ammonia at 4-5 ppm to start and kept checking the level every day until it started to lower which it did in about a week so i then checked for nitrite which was present first reading was 2-3 ppm. as the ammonia was now lowering i then added more pure ammonia to get it back up to 4-5 ppm. kept checking levels over the following week and all was going well! nitrites off the charts and ammonia lowering over 2 days so now only adding pure ammonia just to keep feeding the nitrites but not letting the ammonia go over 4 ppm. So i now check for nitrates and my first sample had a reading over 80 ppm so i am now thinking yes this is doing well only 2 weeks in and already got plenty of nitrates present. this is where im getting worried.... the ammonia is lowering every time i add the amonium hydroxide but the nitrites are still off the charts and my nitrates are now well above 160ppm they have been like this for a week, when will the nitrites come down? how long do i need to keep adding the ammonia for? im worried that the more ammonia im adding is creating too much work for nitrates to handle but at the same time if i just stop the ammonia dosing then the cycle will just stop and starve the bacteria. any suggestions please would be much appreciated.

 

[gemach7]

Nitrates are only removed from the system by WC and plants. To get your nitrates at a manageable level before you add any live animals I would do a 50% Partial water change 3 days in row should get you down to 10ppm.


Sent from my iPhone using Aquarium Advice

 

[Fel]

NOBs (Nitrite oxidizing bacteria) take longer to establish and replicate than AOBs (ammonia oxidizing bacteria), they also tend to do much better at a higher pH (7.5+). Because AOBs produce nitric acid you may have a low pH, if it's in the 6.5 range it could be greatly reducing the rate at which your NOBs can populate the tank.

If your pH is good just be patient, dose ammonia every other day or so, you can do some small water changes mainly to add some micronutrients to the water but personally I don't believe in doing a massive quantity of work just to see what your numbers are. If nitrates are present the tank is cycling and you simply need to be patient. You will need to do one massive water changes at the end to remove nitrates.

Sent from my HTC6515LVW using Tapatalk

 

[gemach7]

I read wrong, saw the160ppm and thought nitrates lol.


Sent from my iPhone using Aquarium Advice

 

[jaybarks]

thanks for the info FEL. have noticed a sudden drop in ph recently, was initially very high at 8ph but ammonium hydroxide naturally raises the ph quite high doesn't it. but yesterday it was at 7.2 then today was 6.0 (too low for cycling) i presume that was from all the nitric acid produced by the AOB'S. i have corrected this today by using a mineral additive which also buffers the ph. now getting a reading of 7.4. suppose i shall have to keep a close eye on the ph from now on. i have 250L ready for a big water change. so i should carry on cycling as i am with no small water changes yet?

 

[ScotJudd]

Hi Jay. You are doing fine. Keep temp above 80f and Ph at or above 7.
You do need to keep feeding the tank with ammonia to about 4ppm but this will result in extremely high nitrite and nitrate levels. I am of the opinion that you should do a water change to bring the nitrites and nitrates to a readable level on your test chart and then top up the ammonia to 4ppm. Once the readings go off the chart you don't really know what they are doing. Eventually you will see your nitrites fall with a subsequent nitrate rise. When 4ppm ammonia is converted to zero in 24 hours and the nitrites are zero as well, nitrates will be very high, then you are cycled. If you are awaiting fish then you can drop the ammonia to about 2ppm daily to keep the filter bacteria 'fed', and then of course do a massive water change before adding stock to bring nitrates under control, definitely under 20 but 10 is better.


Sent from my iPad using Aquarium Advice

 

[gemach7]

thanks for the info FEL. have noticed a sudden drop in ph recently, was initially very high at 8ph but ammonium hydroxide naturally raises the ph quite high doesn't it. but yesterday it was at 7.2 then today was 6.0 (too low for cycling) i presume that was from all the nitric acid produced by the AOB'S. i have corrected this today by using a mineral additive which also buffers the ph. now getting a reading of 7.4. suppose i shall have to keep a close eye on the ph from now on. i have 250L ready for a big water change. so i should carry on cycling as i am with no small water changes yet?

If you have an air pump and stone might help to test a bucket of water before and after has been sitting for 24 hours. If the ph is radically different could indicate you have soft water. If it stabilizes at around 6 you won't have an issue for most fish tbh.

If does drop though would recommend when you get fish and are doing water changes to let your water change water sit for a day before adding so you don't experience a up in ph then a drop.

And yes a ph below 6 is going to effect cycling but isn't bad tbh.

A little below a ph of 6 almost all ammonia is converted to ammonium.
Ammonium is not as toxic as ammonia to fish and plants eat faster.

Using any form of ph up imo without reverse osmosis water is going to be hard to impossible replicate each WC.

I would personally would do a water change so your not doing a nearly 100% wc after the cycle completes imo.


Sent from my iPhone using Aquarium Advice