False ammonia readings caused by something leaching from my sand substrate.

[Zaphod414]

If the sand is indeed "pure silica sand" (as stated), and it is clean, there is absolutely no way the sand is leaching anything. Silica is SiO4. It is chemically inert, and even if it could react, there is not ammonia in it to leach. Silica is as inert as the glass in the aquarium, which is made (mostly) of silica.

If the ammonia readings are real (see good advice above for other possibilities), it is coming from somewhere else.

Their claim that the sand is pure means that they haven't added anything else to it. Some natural impurities can still get through, especially if they are common to the area where the sand is mined. Silica is not what is causing this problem, though. As I have said, I am already keeping my levels of leached silicates at zero using Phosbond. It is some other substance that is leaching from the sand that is affecting my ammonia test result.

I believe I have adequately proven that the mystery substance is definitely coming from my sand, and I'm already all but certain it's not ammonia. I am able to replicate my high ammonia test reading by soaking just some of the sand (never been exposed to the tank or anything organic) in pure water (again, never been in the tank or exposed to anything organic, confirmed to read zero ammonia to start with). After the sand has been soaking in it for just a couple days the water, previously reading zero, tests as if ammonia is present. I really cannot isolate the variables any further without some really expensive equipment, but I think I have done enough already to back up my conclusion that there is something leaching from that sand that is causing my ammonia test kit to read high. Only the sand, some plain water, and a salicylate based ammonia test kit are required to replicate my findings. I have removed all possible sources except the sand.

 

[FreshyFresh]

Just trying to figure out why we're having this conversation if you're without a doubt certain it's your sand..

 

[Zaphod414]

Just trying to figure out why we're having this conversation if you're without a doubt certain it's your sand..

I am pretty certain I have identified the source of the substance as being my sand. What I'm trying to do now is to identify what the substance is so I can determine if it is something that could be detrimental to the fish or if it is nothing to worry about or some shade of grey in between.

 

[Zaphod414]

I think I have finally amassed enough evidence to make some conclusions about my issue. The substance being introduced to my tank from the sand I am using is definitely a dissolved metal. After running some Cuprisorb in the filter for the past 48 hours I am no longer getting a positive reading on my ammonia test kit. It took a bit longer than I expected it to, but over the 48 hours I watched the ammonia test kit read less and less "ammonia" until now it is reading zero. Cuprisorb is a chelating resin that effectively removes copper as well as other metals including iron, cadmium, lead, manganese, zinc, cobalt, and nickel according to the data I can find on it. It probably removes some others as well, but that is the known list. So my contaminant is most likely one of the metals listed above. My chief suspect is iron, as that is known to interfere with a salicylate based ammonia test reaction. To find out specifically would require some more expensive testing. Unfortunately, none of the local LFSs had a store use iron or manganese test kit, so I'd have to send a sample away to a specialized lab. My curiosity may eventually get the better of me, but for now I think I'm going to leave it at mystery metal. So long as the Cuprisorb is removing it I am not too worried about it. I know how to tell if it returns, as well. If I spring for the lab testing and get a definitive result back, I will definitely add it to this thread.

 

[TwoTankAmin]

Iron test kits are easy to find
Seachem, Sera, Fluval, Red Sea, Salifert and API all offer one.

" The JBL ProAqua Test Magnesium Freshwater is designed for measuring and doing routine checks of magnesium content in freshwater aquariums within a range of 0-10 mg/l (ppm). "
https://green-chapter-shop.myshopify.com/products/jbl-magnesium-freshwater-test
$27 plus shipping.