Confused About Nitrate Levels & Fertilizers

hello -

okay so i've done a lot of searching and i'm confused. there is just so many varying opinions on what amount is a safe ppm of nitrate...and of course they completely change with planted tanks to betta tanks to community tanks. I never had to worry about nitrates before I started fertilizing...I just performed my weekly water change. they never got about 20, and that was high. my stock is just one betta and one mystery snail....in a 5 gallon. and 80% of that is obviously the mystery snail.

so I bought NiloCG ThriveC which I love....but now my nitrates are all over the place. I fertilize, they go up....the plants eat some, they do down...I fertilize again....I know plants need nitrates - just what is a good level?? i'm under the impression that 40ppm is safe for a planted tank with a snail and a betta. but I am really wanting the opinion of the Fish Lore community....as I have come to trust this place far more than google.

the directions for ThriveC say 1-2x a week...and I have been fertilizing twice a week. I think this may be a bit much though. what are your opinions? all I have is an anubias barterI and an amazon sword...the amazon sword has a seachem root tab. both are doing great. however, I have had a lot of brownish-orange diatom algae....so i'm considering going down to using the ThriveC 1x a week. thoughts?




my WC schedule has kind of shifted....today is normally my WC day....I just tested my nitrates and they're super high. the color of the test tube is the darkest i've ever seen it....going from dark orange to red....I don't expect it to go to 40ppm...the plants will consume some before my next WC....but I am so scared about them i'm going to go ahead and do a WC today, when my next weekly water change isn't until Tuesday....

so....should I only fertilize 1x a week with the ThriveC? And what is the highest I should let my nitrates get to?

thank you.

PS OH! I also have two marimos...but I don't think they matter. due to very low consumption.

 

How often are you testing your water?

 

I test my water twice a day, everyday AM and PM. I actually really enjoy the testing process....and recording my log.

NH3/4 and NO3 everyday. with 2x per week of GH & KH. maybe 2x pH tests a week...maybe more. I just love my testing water lol. also, I test my NH3/4 twice a day because I am new to the hobby....my tank is roughly 8 weeks old....and I am just confirming all is well....I will probably cut back on my NH3/4 testing in a month or so.

 

You maybe testing too often now that the tank is cycled. It's kinda like someone trying to loose weight and jumping on the scale everyday and not seeing the change they want to see. Their weight may go up, once a week is recommended for that. Now for your tank since it's small, and your concerned about the parameters I would test the days you add ferts. So if that's twice a week test the parameters prior to adding in the ferts. Me I'm lucky to test my tanks twice a month right now. I usually end up doing the Bi-monthly water changes before I even think about testing the water. That's unless I do notice something going on different in the tanks. My small tank has 10x the capacity of you tank does.

 

nothing is in the danger zone. i'm not trying to achieve the equivalent of 'jumping on the scale everyday' in aquarium land. I just want to know what a good max ppm of nitrates are for a fertilized, planted tank. lol. I enjoy testing my water everyday....my parameters are always right where I think they'll be prior to testing...I just want to know if 40ppm nitrate is a safe max level.

 

Yes 40 ppm of Nitrate is what most people consider a safe level.

 

The recommended dosing instructions on the bottle are for high light, CO2 enriched and densely planted tanks.

Your tank seems to be opposite, in which case you can dose half the recommended amount (1 pump per 20 gallons) once a week.

 

If those are the only 2 plants you have you could reduce the dose by more than even half. Anubias is a slow growing plant and with just 1 of those ferts are not really needed and you put in a root tab for the sword so you should be good. The Anubias would be fine with the nutrients from a water change.

 

The recommended dosing instructions on the bottle are for high light, CO2 enriched and densely planted tanks.

Your tank seems to be opposite, in which case you can dose half the recommended amount (1 pump per 20 gallons) once a week.

ThriveC is for high bioload, low tech tanks.

 

ThriveC is for high bioload, low tech tanks.

Ah! You're very correct, my apologies. I glossed over the "C" part and read it as just "Thrive": I always forget that there's a few variations on the standard "Thrive".

It is, so far I interpret from the guaranteed analysis, not a true "high bioload" fert as most of the nutrients are simply diluted 50% from their standard Thrive concentration. Phosphate is slightly lower at ~33%, but nitrate is not reduced in proportion to the other ferts.

Dosing twice a week would be equivalent to dosing standard Thrive once a week. My suggestion above was for half a standard Thrive dose (1 pump per 20 gallons rather than 1 pump for 10) once a week, and that would be equivalent to dosing ThriveC once a week at 1 pump per 5 gallons.

In terms of acceptable nitrate, it's very variable. Quoting myself from another post:

There's a lot of misconceptions around nitrate and copper toxicity in ferts from newer planted tank aquarists. Tom Barr, the developer of Estimative Index and a noted American planted tank expert, routinely breeds shrimp in planted tanks where he doses excess nitrate. This is one post of Tom's at planted tank where he challenges the idea that excess nitrate within the EI method (to which Thrive structures its dosing recommendations) has an effect on shrimp.

Quoting Mr. Barr's specific post:

I would seriously like to know who has done any test that shows that KNO3 dosing is bad, detrimental to RCS in any meaningful way. In fact, I openly challenge anyone to show that there is any impact up to say 50-80ppm of NO3. This means you have ruled out other possible causes, and that it is not mere correlation. There are 1001 ways to kill critters that have NOTHING to do with KNO3 dosing.

The general community consensus is that a reading of, say, 20 ppm nitrate accumulated from ferts and waste is less toxic than 20 ppm from waste alone: a comparable reading of nitrate solely from nitrification is of relatively more toxicity as its an indication of overall high bioload, accumulation of other waste products, etc. I would use 50 ppm as an approximate upper threshold for nitrate (from both ferts and waste).