Originally Posted by goatkeepers
We use black sand, the kind you can buy at petsmart/petco. A live sand....
We use aquarium salt, stress zyme and stress coat.
Well, we lost all but one of the black tetras but all three cory cats are alive.
All the levels are back to normal after being high for a day; could it be that the cycling is done already?? Everything other than nitrates are normal, they are slightly elevated, but not much.
By "live sand" I'll assume you don't mean the live coral sand for marine tanks but rather the planted tank enriched substrate that comes wet in a bag; correct me if I'm wrong, but assuming this is what you mean, it's fine. it will raise pH a bit for a few weeks (according to some manufacturers, depending upon the one you have) but will then settle and be inert (no effect on pH or hardness). I agree with Mikaila and redchigh, do not use the CO2 until the tank is stable. This may take several weeks.
Once it is stable, the pH will be close to the tap water pH. Depending upon the KH of your tap water, the pH will remain close to this or drop slightly due to biological processes; the more hard your tap water (higher KH) the more it buffers pH to stay where it is. Adding CO2 then will lower the pH and you will have to monitor it as depending upon the KH this will be variable and you want to avoid sudden fluctuations or drops.
I have some warnings on the salt and stress zyme.
Salt: a debatable issue, you will find aquarists here and elsewhere that are pro and con on salt. My advice is never put salt in a freshwater tank; perhaps as a specific medication for a disease issue, but never as a general principle. Different fish have different tolerance levels for salt. Corydoras are highly sensitive to salt and it can kill them in time depending upon the level. Several knowledgeable ichthyologists have noted that in their habit, those corys that occur in coastal rivers will never venture into any brackish water but remain well back in totally fresh. Dr. Stanley Weitzman, who is Emeritus Research Scientist at the Department of Ichthyology of the Smithsonian Institute in Washington and an acknowledged authority on characoid fishes, has noted that soft water fish have a very low tolerance of salt. Dr. Weitzman writes that 100 ppm of salt is the maximum for characins, and there are several species that show considerable stress leading to death at 60 ppm. 100 ppm is equal to .38 of one gram of salt per gallon of water. One level teaspoon holds six grams of salt. I can assure you that corys are just as adversely affected as characins.
Stress Zyme: From API's website, this info.
Improves the development of the biological filter and helps clean a dirty aquarium. Contains over 300 million live bacteria per teaspoonful. Breaks down organic compounds that cause dangerous conditions such as ammonia and nitrite poisoning and low oxygen levels. Continuous use assures an active biological filter, cleaner aquarium, healthier fish and good water quality. No refrigeration necessary. Use when setting up and maintaining an aquarium.
While I have in other cases recommended biological supplements, I do not recommend this one. "Cleaning a dirty aquarium" is open to interpretation. Breaking down organic compounds is the job of normal bacteria in a balanced aquarium, and I do not recommend adding products that affect this is some way, as this one clearly does if their information is to be believed. It also raises ammonia initially. I would not recommend using this product further. The fewer chemicals and "substances" that go into an aquarium, the better will be the health of the fish long-term.
On the nitrates, what is the actual number? Nitrates are normal (some planted tanks have zero, some low nitrates) but the number is needed in order to determine if there is or isn't an issue looming with nitrates.