cycling vs. 100% water changes

[fishyfishfish425]

i keep typing this, and when i am finished, my computer spazzes and goes "back" and it gets deleted so i'm going to try to "abbreviate" this as much as possible...

long story short, i have a 10 gallon, filtered tank heated at 80 degrees. my betta has lived here alone and i have done 100% water changes every 14 days (on average, depending on conditions) and he has always been very active and healthy.

i posted here earlier this week because i bought a small school of bloodfin tetra as a "christmas present" for my betta...and mistakenly followed the store clerk's instructions...since my post i followed everyone's advice and decided to quarantine the betta and the tetra into smaller, heated, filtered tanks, since the tetra were mysteriously dying and my betta got really sick really fast. i figured while everyone was in the quarantine tanks i could try to cycle my aquarium for the first time..that way the time it would take for everyone to get "better" the tank would be cycled.

however the tetra continue to mysteriously die one by one, i'm not sure if they're dying from stress since the school is getting smaller and smaller, or if they're just diseased--though they show NO signs of disease from what i can tell. its draining because i'm not sure why. they seem totally normal and active, then a few hours later i'll come home and one more will be dead. i read reviews for the place i got them from and SO many posts were saying how the fish were diseased.

basically, looks like it will be the betta will be alone in the 10 gallon tank again. i sort of want to just do a 100% water change in the large tank and put him back in, and continue with the 100% water changes every 2 weeks or so.

should i let it cycle? or just continue with the 100% water changes? i don't think i want to try to get any more tank mates soon...this whole tetra mass death is depressing and draining.

[Oldfishlady]

Sorry you are having so many problems...it can be frustrating....sometimes its just sick fish to start and long with the added stress from moving can do them in.....

Since your tank is filtered-it will cycle as long as the beneficial bacteria have a food source, oxygen and surface area...it will happen in time.....

You don't need to make 100% water changes, while removing all the water won't hurt since very little of the BB are in the water column itself-they are sticky and adhere to all the surface areas in the tank, in the top layer of the substrate and in the filter media and if you don't over clean and remove too much of the BB you can take all the water out every day and be fine...you just don't need to......with one Betta in a 10gal filtered once the nitrogen cycle is established 50% weekly with vacuum should maintain water quality....

During the cycling process if you have a water test kit make a second 50% water only based on test results of ammonia, nitrite 0.25ppm or greater-until you have nitrate of 5-10ppm without any ammonia, nitrite spikes...remembering that some additives can cause skewed results so you need to adjust for that and live active growing plants can change time-lines of the process among other things.

Without a water test kit you can still safely establish the nitrogen cycle with the Betta-Along with your regular 50% weekly with vacuum-make a second 50% water only...it can take 4-8 weeks to establish the nitrogen cycle