Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
Many pet store people do not know the right answers.
1) If you need to add nitrifying bacteria use a product that contains Nitrospira. Does not sound like you have a problem that way, though. Zero NH3, NO2 = nitrifying bacteria are doing fine.
2) 10% water change once a week is way too little. I was regularly doing 50% water changes weekly, and it is just fine to do as large and as frequent water changes as you want. The trick is to use water that matches the tank water: Same GH, KH and TDS. With the fish you have somewhat softer water is fine. Neons and Platies have been raised in captivity for so long they accept a very wide range of conditions.
3) The 0 ppm for NO3 tells me the plants (and algae) are using up all the nutrients you are adding from fish food and whatever Flourish product you are using. (Which one is it, by the way?)
Here is what I would do:
Turn the CO2 back on, but start slowly, allow the fish to get used to it.
Do much larger water changes, perhaps 50% per day for a week or so.
Lift the light higher, or put a screen between the light and the tank.
Put the light on a timer and set it for a Siesta period: On for 6 hours, off for 2 then on for 6.
Add a complete fertilizer program like the Estimative Index.
If you need to leave the tank for a while do not feed. The fish will be fine.
If you cannot do this, then use the Tetra Gel type of food.
Get more Neon Tetras. They are a schooling fish and will be much happier with a dozen or so.