Re: DIY C02 recipie doesn't last

> From: gtong at sirius_com (G.Tong)
> Subject: Re: Ammonium
> Help. Where does ammonium come from? I thought ammonia was what the fish
> secrete. If so, something must first turn ammonia into ammonium ... Where
> does that something come from? TIA.

ammonium is the ionized form of ammonia and it exists in a chemical
equilibrium with ammonia that is pH dependent. At pH we are interested
in it's mostly ammonium. Some interesting articles on the toxicity
of ammonia/ammonium by Neil Frank in the early issues of the APD if
I recall. Pls correct me but I think fish excrete urea which breaks
down to ammonia. Perhaps it is the same thing.

> A related question: when one has a biofilter in a heavily planted tank,
> would the bacteria and the plants be in competition? If so, who gets what
> first?

Yes, they would compete for ammonium. It doesn't matter how much is
converted by biological filtration; any is too much. (IMHO)
OTOH the recipe for PMDDs calls for KNO3 (potassium nitrate)!
It would not be wise to add ammonia to a (plant) tank unless perhaps 
there were no fish in there at all.

> From: duncand at sprynet_com
> Subject: DIY C02 recipie doesn't last
> I'm running one bottle on a 75g and one on a 50g. 
> The recipie I got from a FAQ 
> file off of the AquaLink web site calls for 3 cups sugar and two tablespoons 
> yeast (roughly 1 packet) to the two litre bottle. file states that this is 
> supposed to last about two weeks. I'm barely getting one week on mine.

Try 1 to 2 cups of sugar for a two litre bottle. Use 1 teaspoon of yeast
only. 2 tablespoons would react too quickly. If your room temp is too
high, it will also ferment faster than you want. I also recommend that you
have two bottles operating in parallel. Alternate the changes so that
each bottle is recharged about every 4-6 weeks. They continue to put out
CO2 but a much reduced rate for a long time. What a nuisance. I hope to
have my needle valves very soon and no more yeast mixing! Next, I'll be
wishing for a pH controller.

Steve     Vancouver BC