Beginning My Fishless Cycle - Please Advise

[KittyKat]

You can't *really* say that the tetras are "completely fine" because the effects will only be visible in weeks to years sort of time frame, not days.

 

[blagger]

I'd keep testing every day until you have seven days consecutive with no water change and the ammonia and nitrite both stay a solid zero. I'd also say that I am a bit concerned that seemingly your nitrates haven't noticably increased in a while. Maybe they did, or maybe they didn't. 40-80ppm is a pretty wide variance, although the colors do look very similar on the API kit. I'd do a water change to lower the nitrates to 10-20ppm, so that you will be able to notice what the value is. Another option to get a more accurate reading would be to add 1 mL tank water, and 4mL tap water (assuming your tap has 0 nitrates) and add the reagents as usual. Read as always and then multiply your result by 5. So, if you had 100ppm, adding the 1ml tank water with 4ml tap water would only show up as 20ppm. And 50ppm would show up at 10ppm on the test with this method.

Have now done these Nitrate tests.

All tap water shows 10ppm

4ml tap and 1ml tap shows 20 to 40ppm

All from tank shows 40 to 80ppm

The ammonia and nitrites are both 0ppm.

 

[eaglesaquarium]

So, your tank is probably on the end towards 80ppm, rather than the 40ppm.

 

[blagger]

So, your tank is probably on the end towards 80ppm, rather than the 40ppm.

Thanks. the colours for those two are so close its hard to tell which it is.