Aquarium Tip #6

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I recently emailed Dr Tim Hovanec to find out why we should not use ammonia removers or ammonia binders during a cycle. [EDIT] Included is an added follow up where I had additional questions that he answered for me.

My email to Dr Tim:

I’ve a question about ammonia binders and ammonia removers. In one of your articles you say not to add ammonia binders because it lengthens the cycling time. In another article you say not to add ammonia removers because it lengthens the cycling time. Is there a difference between binders and removers? (IE: do removers really remove the ammonia, or is the word just used as a selling technique)?

Seachem insists that Prime will not interfere with the cycling process because it doesn’t bind the ammonia used to feed the nitrifying bacteria. When you recommend not to use ammonia/binders during the cycling period, do you feel this should also include Seachem Prime? If so, can you help me understand why?

May I please have permission to share the contents of our emails with one of the forums I belong to, and on my personal site (I will not share your email address, only the contents if you give me permission).

Thanks for your patience and for getting back to me!

Dr Tim’s reply:


You can share this.

Some products claim to bind the ammonia, other products claim to remove the ammonia while still others claim to make the ammonia non-toxic.
Our (DrTim’s Aquatics) recommendation for all this is that all of these products will lengthen the time it takes to cycle so they should be used sparely. Do not use them to ‘establish’ the cycle or help the bacteria – they won’t. Use them when first setting up the tank, with large water changes and do not overdose except in emergencies.

As for Prime – SeaChem has never fully explained from a scientific standpoint how this works. Furthermore, research has shown that it is ammonia (NH3) that the bacteria use not ammonium (NH4+). The reason is that NH4+ is a cation and cannot move across the bacterial cell membrane (this is also why ammonia is the toxic part of the total ammonia – only ammonia [not ammonium] can move across the gill membrane). Therefore if you bind the ammonia to something the ammonia is no longer available to the bacteria because the ammonia is no longer a free ion. Furthermore, we talk to hobbyists every day who are having trouble cycling their tanks and find that a majority of these people are overdosing Prime which results in their tanks take longer to cycle.

As for removers – these products completely remove the ammonia from the water. They work but large scale use of these will lower the pH which the nitrifying bacteria do not like because it causes the total ammonia to shift to almost all ammonium which the bacteria can’t use and so it takes longer to establish the cycle.

Products that claim to make the ammonia non-toxic are trying to reduce the pH so the total ammonia goes to ammonium. But for almost all tanks the pH will bounce back up so some to the total ammonia goes back to ammonia (the toxic form) but the water chemistry is now messed-up.

DrTim’s Aquatics, LLC

My Reply

Thank you so very much for helping to clarify things for me! I only have one more question. You mentioned that the nitrifying bacteria cannot use the ammonium. I use your Ammonium Chloride Drops with your One & Only all the time… Is the Ammonium Chloride Drops not the same ammonium that the good bacteria can’t use?

Dr Tim’s Reply


Some basics – ammonia is NH3 while ammonium is NH4+ (note can’t write the chemical formula correctly in an email).

TOGETHER they make up the total ammonia in the water.

What percent of the total ammonia is ammonium and what percent is ammonia is determined by the pH (mostly) but together they will always equal 100%.

At a low pH (below 5.5 or so) 100% of the total ammonia is in the ammonium form.
At a high pH (say above 12) 100% of the total ammonia is in the ammonia form.

In between pH 5.5 and 12 the percentage of each varies.

So we sell you ammonium chloride but when you put the drops into your aquarium water (which most likely has a pH between 6.5 and 8.5) part of the ammonium will stay ammonium but part becomes ammonia.

This is what when the pH of the aquarium drops below 6 the bacteria do not work very fast because nearly 100% of total ammonia in the ammonium form.

The graph below shows you the percentage ammonium-ammonia at 3 different temperatures.

Make sense now?

Unionized ammonia chart

Unionized ammonia chart

My Reply

I think so. In your cycle troubleshooting tips you mention not to allow the pH to drop below 7. Is this just a safe number, or should we really be shooting for 7 as the lowest number before a water change is needed?

Dr Tim’s Reply

7 is safe number is can go down to 6.5 but after that a water change is needed