NO3 Dosage - Hell, is it normal?!?

[geoffrey]

Guys,

Aaaa.......anyone dose more than 40~50ppm of NO3 per week with KNO3? Just want to know that I'm not alone.

[PeterGwee]

Mmmmm...weird. I do doubt the test kit I use as always..imagine I dump in 10ppm worth of KNO3 and it shows zero? Then after a day or so..wah..30ppm!!! Come on..cannot be...my bioload is low or close to moderate. Geoffrey, I think you should doubt the test kit..I personally cannot believe the readings at times....Imagine Tom Barr's max uptake is 4ppm per day at very high light condition which would give about 28ppm-30ppm uptake in a week..40-50ppm..unless you starve them pretty good for quite sometime.

[Allen_1971]

errr that seems a bit excessive... unless you have a fish free tank... wats your bioload vs plantload like?

[naturetan]

geoffrey, fyi, I'm currently running my tank of NO3 value >50ppm.

[PeterGwee]

Naturetan...>50ppm? Ermmm...you mean to need to dose more than 50ppm of KNO3 to keep up with the uptake or is your tank NO3 now more than 50ppm? If your tank NO3 is more than 50ppm now, then I think either your test kit has gone bad or is simply inaccurate or something is seriously limiting the uptake of NO3.

[vinz]

Ugh... I keep forgetting to post this...

I bought a new NO3 testkit (Sera) to replace my old one (easily a year old) which was running out. Out of curiosity, I tested the water with both kits... old kit -> 40ppm, new kit -> 20ppm.

[PeterGwee]

Haha..Vinz..pretty much said about the kits..I bought the first Sera phosphate test kit and the measured PO4 is 1-2ppm. 3 weeks later, bought another same brand kit and the test results is 0.5ppm!..Crap..I think the best "cheap" kits can do is to detect for presence rather than accuracy. My teaspoon set is better at it. Imagine ppl complaining about distorted leaves and algae when they measure presence of NO3 and PO4 as well as dose other stuff..(points all to the problematic test kit..actually I was thinking the root of the problem is usually the powder reagent..slightly less or more affects the result? Plus the caking problem with PO4 powder reagent doesn't help. Maybe Sera should consider changing their powder reagent into tablet form..much easier to test..just dump the tablet in and shake the hell out of it. [] )

[Allen_1971]

well PO4 kits are notoriously bad... mainly due to poor shelf life. NO3 kits should be more stable I think... generally shouldn't get that much of a deviation.

[geoffrey]

Weird is exactly what I am thinking too. I use to do about 20~30ppm per week. What's weird is this happened only this week right after I fiddled with more T/E.

I don't discount faulty test kit, and I share Gwee's experience too. That I certainly is going to confirm tomorrow and Sat with a new kit I bought today.

I dose regularly on Tue and Fri night. My tank usually measures about 10ppm NO3 the night before and would top up to 20ppm on the actual night.

2/5 (Fri) - top up to 20ppm and doubled T/E.
3/5 (Sat) - abit more T/E
5/5 (Mon) - Detected some BBA and NO3 measured <5ppm (the colour is between 0 and 5). I dosed 15ppm then instead of Tue. Suspecting something amidst.
8/5 (Thu) - this morning, certain that BBA is on the increase. Measured NO3 at ZERO!! So I dosed immediately. This time 20ppm from KNO3 and about 9.5ppm from Aqua.

If this goes on, I will be doing about 40~50ppm!!

BTW, I also maintained my high T/E, just to confirmed, in case test kit turns out ok, that I should lower it.

[PeterGwee]

Geoffrey...from what I can see from your tank, it is indeed densely planted..cannot see much empty space. ..BBA linked with NO3? I thought BBA is an actual indication of low CO2 or inconsistent levels of it. From this encounter, it seems like your T/E is pretty much limited..but I don't think the uptake can be so dramatic though..it ain't possible..or is it? []

Its good to see your NO3 dropping as I had yet to see mine except for tremendous drop in PO4 level...weird..But that is possible. I am now playing with my CO2 level..raising the KH up to 5 to reduce pH fluctuation throughout the night due to stopping of injection of CO2. Hope to hit about 20ppm in the morning while 30-35ppm when lights off. Seems to be working as I am looking at the pH monitor and the movement of pH is indeed little..0.02 shift per hr. []

[geoffrey]

Yup, plant and fish load is important here.

Plants - cryst easily 9 stands; ozelet; oriental; E schlueteri x 2; A. henkelianus; H. corymbosa; a lawn of tenellus, there's more but these are the one I think are significant uptakers.

Fishes - boy, it's heavy! And strange I never seem to be able to get NO3 from fish food!!

BTW, light is 2.6WPG, CO2 last is 20~30ppm (coral).

[PeterGwee]

Do feedback on findings geoffrey...I'm thinking of not using testkits to judge but am afraid it might kill my fishes with OD of KNO3..LOL [] ..I think Tom would say no as long as large water changes are done weekly and CO2 is kept in optimal range.

[geoffrey]

Gwee, I always have BBA when my NO3 runs too low.

I thought so too, it should not be so drastic a change in uptake with a change in T/E. But I'm not sure now.

[vinz]

T/E = trace elements?

[PeterGwee]

Yup..aka short form.

[naturetan]

PeterGwee, I would very much hope that my test kit is faulty. Read this for my problem. It's more like a substrate fertiliser leakage problem. You think the test against tap water will show its accuracy? Tap water measured around 0-12ppm, but tank water 50-100ppm! It should be accurate right?

Previously invaded with BBA. After dosing most of the macro & micro nutrients (except NO3), BBA now has practically reduced significantly. However, NO3 still maintain high. Dare not take the risk of dosing NO3, for fear of poisoning my fishes. Got to have patience and wait till substrate fertiliser get exhausted. Maybe 1 year or so?

If only some kind soul could loan NO3 kits just for a test to verify, I've practically given up buying such kit due to no budget. Currently using Tom Barr's cheaper method of dosing without kits. If I know NO3 is low, I will love to dose that too - just to wipe out the remaining BBA!

[Plantbrain]

Toss the test kit.
You'll spend more time fretting than getting anything done.

I'd just see what the local tap water has, and then make your own dosings based off that and a water change. Guess 2x more during the week, and be done with it.

4ppm a day is a lot of NO3. There's likely no way much above this unless you are pulling out many kilos of plants every week.

I've driven the NO3 up to 75ppm for 3 weeks once but had low PO4 to see what might happen, not much really. But the longer term effects would likely cause issues. This tank had no fish but lots of snails.

Keep the NO3 down, you'll have less issues if you do.

Also, it takes less time to do the water change/re dose than most spend on testing their NO3 and PO4.

Regards,
Tom Barr

[PeterGwee]

Mmmmm...Tom, personally I would have want to toss the kit out but due to the data given for our tap, which has a rather big range of 0.5-15ppm of N, I would keep it for a purpose. (My tap as measured by the kit tells me that it is zero which is not possible...might be 0.5ppm perharps.

NatureTan, Check your CO2 levels and if they are good and dandy, dump your NO3 kit...it is worthless.

[FC]

I am about to give up that first 6 liquid drops, then 2nd the little spoon powder, again third 6 liquid drops craps, real craps. Then wait for 5 minutes, not longer, r-e-a-l-l-y wait because I often past the time and had to re-do again. That's NO3. And then PO4. Wah...

After all, I do not have alage at all for years (other than the glass wall)! They are only good for the beginning when I need to understand the plants' consumption rate. I will forget them till algae strikes (finger crossed).

[naturetan]

My tank KH is 3 with about PH 6.4, more than enough CO2. Think have to consider dumping my NO3 kit and carefully start dosing NO3.

Luckily didn't spend on PO4 kit, thanks to FC previous helpful & kind advice, else it's expensive & heart-wrenching to throw kits just like that! []