That's completely false. I put 10+ppm each time I dose in my 125g and my fish are doing absolutely great. You'll have several people come on here and tell you it's sare. No worries. The only time you'll have to worry is if you get the Nitrates very high for an extended period of time (over 40ppm I would imagine).

 

Thanks Bryeman. So do you think I could just put in 5mls of Flourish Nitrogen in one dose and get the nitrates up to 8.7 ppm? This won't affect the fish at all?

Has anyone else had similar experiences of increasing nitrates by 10+ppm in one dose? I just want to be absolutely sure before I increase the dosage.

 

It shouldn't be a problem since most people who dose using the EI method are generally putting a lot more than that into their tank at one time. If you are worried about it you could always put in half right away (mix with some water in a bucket first, then dump in if you would prefer) and then the other half an hour later. No matter how you do it, you shouldn't have any issues. Hopefully some other experienced people can come along and back up my statement.

 

unless the fish are very sensitive to it, you should not have a problem.
I add upwards of 15-20ppm NO3 per day to tanks that contain fish and they are fine.

if you supply enough Nitrate, you may soon notice you are lacking in other things
so consider balanced dosing of all macros, with traces as well.
Just throwing that in as a disclaimer

 

SeaChem's recommended dosing is very very conservative. You might want to go with their dosing recommendations to start, to see if that will improve your plants. If you have duckweed, I understand they are nitrate hogs, you might still have to dose more than SeaChems recommendations. Anyway, you can ease into it gradually. Are you using co2? what kind of lighting are you using? Your fish can tolerate 40 ppm, some say over 80 ppm so I wouldn't worry until you get above 25 ppm.

 

Alright great, thanks everyone, really answered my questions. I'll be off to dose my tank by 5ppm and then another 5ppm a little later, as suggested. Maybe I'll go up to 20ppm if the fish can handle it.

I already use Flourish, which I believe contains some trace chemicals and some iron. If the plants do other deficiencies, I'll probably get some Flourish Potassium/Phosphorus. Not ready for EI yet.

I haven't used CO2, since the plants were growing fine before I took out some fish and the nitrates went down to 0ppm. I think adding the duckweed also contributed to the flat nitrate level. They covered the aquarium twice before stopping growth. If they start growing again, I think I'll just take them out regularly to keep a low population.

Lighting is 30 watts CFL 6000K, which is my only option at the moment. It's probably far from ideal, but I don't have the most demanding plants either, bunch of anubias, a tiger lotus and some duckweed.