Originally Posted by kjg1029
and when we get to the water conditioner and I was telling her that Seachem prime is the best for cycling her smaller 2 gallon, and its good for uncycled tanks too. well he store guy over hears us talking about it and butts in with "oh no, we dont use prime any more,we refuse to carry it, its nasty stuff. it deprives the water of oxygen, its formaldehyde" ect ect....
he loves the seachem brand stuff, just not prime I guess lol. he said he uses the other (pointed at a powdered conditioner) seachem stuff.
so ive done some looking around and it seems that unless it got really Hot, then its not going to actually form FOMaldehyde....so is there truth to this?
the stuff he was saying sounded seriously bad! but I doubt yall would suggest a bad brand of conditioner over and over again!
I'm going to guess this was an older guy? Been in the hobby for a few decades? He's got some good info and some old info and some incorrect info. Sooooo, let's break it all down.
1. Seachem Prime deprives the water of oxygen.
This is technically true but partially wrong.
First, the true part. Any dechlorinator can reduce the amount of dissolved oxygen in the water.
If you read the fine print, Seachem Prime has the following usage instructions: "For exceptionally high chloramine concentrations, a double dose may be used safely. To detoxify nitrite in an emergency, up to 5 times normal dose may be used. If temperature is > 30 °C (86 °F) and chlorine or ammonia levels are low, use a half dose.
" Warm water holds less dissolved oxygen, and if there is little chlorine present, the leftover dechlorinator starts breaking up other things in the water, like ammonia and nitrite. And oxygen.
Now for the wrong part.
Back in ye olde days of aquarium keeping, some dechlorinators were made with concentrated sodium bisulfite, which if you overdosed, you wrecked your pH and suffocated your fish. Today, any conditioner that claims to neutralize chlorine, chloramine, and ammonia all in one go is usually made from sodium formaldehyde bisulfite and diluted to the point where you'd have to really FUBAR the dosage. In the case of Seachem Prime, safely usable up to 5 times the regular dosage as long as you follow their instructions.
2. Seachem Prime contains formaldehyde.
Nope, that's a myth.
But there's formaldehyde in the name!
If you've ever smelled the chemical formaldehyde, you'll never, never, never mistake it for anything else. Here "formaldehyde" refers to the reactive group that's just one part of the entire chemical. Prime calls it their proprietary "complexed hydrosulfite salts", which is probably some variation of sodium formaldehyde bisulfite AKA hydroxymethane sulfonate, the same stuff in Kordon Amquel.
That's pretty stable stuff. You'd have to deliberately heat it to an absolutely ridiculous temperature to maybe(?) get it to breakdown into formaldehyde (something like 200-300deg Celcius?) Not likely to happen by accident, not even if you lived in Death Valley or the Sahara!
This myth probably sprang up from the fact that - chemically speaking - formaldehyde was used to neutralize ammonia. From Seachem's Ammonia Management pdf
: "The classical reaction of ammonia with formaldehyde to form methenamine is the principal of most ammonia removing conditioners. It may be used either directly or as a bisulfite complex. ...Seachem has three conditioners formulated to remove ammonia: Safe, Prime, and AmGuard. All three remove ammonia by chemically converting it to a nontoxic cyclic amine ...While Safe and Prime are designed to handle the moderate ammonia concentrations found in municipal water systems, AmGuard is designed to handle much higher ammonia concentrations. ...Overdosing [with AmGuard] should be avoided, since excess will react with oxgyen if free ammonia is not available."