Observations: Rotala Macandro (1) - Nitrates (2)

[tackful]

Hello All,
My new rotala is growing well and has finally reached the surface. My intention is to allow it to continue growing and to spread horizontally across the surface, but the plant seems to have its own ideas. Rather than doing so the stem simply bends and buckles back and forth underneath as though it wishes to avoid contact with the air at all costs. Is this typical behavior for this plant?
Now for nitrates. I have been following EI dosing for my 29 gal tank, along with the weekly 50% wc. However, my nitrates climbed up as high as 80+ppm, so for the past two weeks I discontinued dosing nitrates completely. Current level is somewhere between 40-60ppm, even with another 50% wc. Is it possible that the fish are simply producing enough for the tank on their own? I have tetras and some pencilfish, about 20 total, which I don't think is a lot, and the water is perfectly clear. Thanks.

 

[SnakeIce]

have you calibrated your test for nitrates? Even the "professional" tests have to be calibrated to be accurate.

The other thing you might need to adjust for is that the EI suggested dosing amounts are for max light, pressureized CO2 at levels potentially above what your fish might stand. So if you don't have all that going on you might cut the dose size down some. Oh and the dosing is for true water volume not whatever the nominal tank volume is.

So if you don't have max light and CO2, and your actual water volume is less than it is assumed to be that might partially be the cause of the high readings. EI with 50% water changes would reach double your dosing amounts if nothing gets taken up by the plants. So if during the week you are dosing enough for 20 ppm in the water column, a water only tank with 50% changes weekly will sit at 40 ppm levels after some weeks time.

 

[tanker]

Your incoming water maybe high in Nitrates, did you test your "new" water??

 

[tackful]

I do have pressurized co2, although with only 55w over a 29 gal tall I guess I have a low light tank. As for tap water, N= 0. Tank now tests 40ppm N after yet another 50% WC.
Haven't calibrated the test kit yet. Will read up on it and do so.
Sorry for late response and thanks for replies.

 

[SnakeIce]

I had a low light 20 gallon tank(30 watts normal flourescent), and I used the EI "recipe", but cut it down to the point I was only adding 20 ppm of nitrate a week and just dosed once for macros and spread the micros out during the week.

I did eventually notice that the tank got to where that wasn't quite enough to last the week but that was easy to bump up a little. More growing tips on the plants you have mean more uptake. You would have to create an account at Aquatic plant Central to use this fert calculator, but it would be worth it just for this resource. I compared the recommended EI dosing with my projected reductions to see if I had the measurements thought out correctly.

http://www.aquaticplantcentral.com/forumapc/fertilator.php