This is a discussion on stress free cycling within the Beginner Freshwater Aquarium forums, part of the Freshwater Fish and Aquariums category; -->
ive been fish in cycling a 20gal for about 4 weeks. for the first 10 days i tested and stressed over the next spikes. ...
ive been fish in cycling a 20gal for about 4 weeks. for the first 10 days i tested and stressed over the next spikes. i figured the answer for any spike or problem the test found would be a water change. so i put the test down and started doing 50% water changes daily. its a bunch of work but i stopped worrying. if i see odd behavior i wc 2x a day. now for the disclaimer. im new to this and i have possibly missed a big picture thing that someone will correct. but it seems to be working. these platys are the happiest and healthiest ive seen in my 4 months.
Doing 50% water changes once or twice a day is counter productive. The bacteria colonies you need (Nitrosomonas and Nitrobacter) to support the bio-load can't develop and expand if there is not sufficient ammonia and subsequent nitrite. Your water changes remove the necessary elements for balance. Yes, you need a partial water change if/when there is a spike, but not normally and not daily or twice daily. If/when you change to much water too often, it's like beginning anew every day - not what you're after. Relax and let the cycle happen.
A 50% water change will only reduce the levels of ammonia and nitrite by half, you can never get both to zero with water changes alone.
With fish in the tank, daily changes are necessary or the fish will suffer needlessly and their lifespan will be reduced. The damage caused by ammonia and nitrite are permanent, it does not heal over time.
The bacteria will multiply at the same rate regardless on if there is 0.25 ppm or 0.50 ppm Ammonia. They replicate at full speed until their food source (ammonia) is exhausted. I believe I have also read that the bacteria will suffer and grow slower if ammonia/nitrite levels get too high.
Twice a day would be a bit excessive though. If you're only getting a trace reading on the test kit, 0.25 ppm, I wouldn't worry about that and let things sit. But at 0.5 ppm or higher with fish in the tank ... water change. You can try adding Prime every 48 hours to detoxify it, but I would still keep the ammonia below 0.50 ppm when fish are in the tank.
I believe that it depends on the bio-load Geo - I have had fry tanks that never developed BB or cycled because of low bio-load and routine water changes. With a high degree of fresh water, beneficial bacteria is unnecessary because there is little/no ammonia and no nitrites.
If there are fish in the tank, please err on the side of caution, always. The damage (permanent) that any even minimal amount of ammonia or nitrite can cause a fish is not worth anything less.
Live plants, especially floating, will solve this immediately. If for some reason plants can't be added, a bacterial supplement will get the cycle going faster. Tetra's SafeStart and Seachem's Stability work. There is another marketed by Dr. Tim Hovanec but I can't remember the name.
Using a conditioner that detoxifies ammonia and nitrite during the cycling is wise. Seachem's Prime and APs Ultimate both do this. A 50% water change on alternate days using either of these will work.
With fish in the tank, I believe water changes are dependent on number of fishes, and volume of water, along with foods offered.
Few are those who stock sensibly when placing fish in uncycled aquariums unfortunately for the fish.
Even fewer people ,grasp how much food to feed without overfeeding in cycled or uncycled tanks.
I believe OP is right on with their approach.IMHO