I was wondering if its normal to have 0 Nitrates and if this is a problem?
I have 3 seperate 6.6 gallon "bookshelf" tanks from petco, each has one betta, one zebra snail a ton of MTS, sand substrate, live plants, HOB filter with sponge, no carbon in filter and some driftwood, all are cycled and heated, no co2. Most of the time my nitrates are low... between 5.0ppm and 10.0ppm. I use the API master test kit. Tank one has been cycled for about 2 yrs, tank 2 for about a year and a half, tank 3 about 4 months. I usually do about a 1 gallon water chg once a week with a small vacuming, sometimes I wait up to 2 weeks.
I recently went out of town for a while. I did a partial wc the day before I left, June 17th. My son did a partial wc for me on June 24th while I was away. I returned on July 6th and all looks well in all the tanks. Today I tested the water parameters just to see what was what before I do a wc. Tank one and three have the same parameters, ammonia 0, nitrite 0, nitrate 5.0, tank one ph 7.4, tank 3 ph 7.8. However, tank 2 has ammonia 0, nitrite 0, ph 7.4 and nitrates 0.
I use the same test kit for all three tanks (I have 12 test vials and use 4 for each tank making sure I dont cross contaminate them to ensure I am getting correct readings) however I use the same bottle of test liquid for all 3 tanks. And yes I shake the bejeezes out of the nitrate test bottle solution before putting it in the vial and then do the same with the vial. The kit is fairly new as I had recently run out of test liquid, approximately 7 months old, the expiration date is 11/2016. I use Prime for water chgs. I used API root tabs (3 per tank) about a month before I left town, around the middle of April.
The tank in question, tank two is planted but not as heavely as tank one yet tank one has nitrates of 5.0.
I guess my question is why 0 nitrates in this one tank and should I be concerned? Should I do less frequent water changes? Add more ferts? All the plants look healthy although my hairgrass is taking forever to fill in...
What do you guys think?