Insane Nitrate dry dose

[Aquafreak]

I've been adding KNO3 dry to my 33 gal tank. It's 80% planted with glosso, has steady 35ppm co2. At first I was dosing 1/4 tsp KNO3 and 3 drops of fleet enema and I wasn't getting much reading from the test kits, so I upped the amount of fleet and KNO3 slowly daily. On the 3rd day I'm up to 16 drops of fleet and 7 tsps of KNO3 to get 1ppm P and around 5ppm N. Does this sound insanely too much to dose? Or is the tank really eating up all that P and N?

[Tempest]

Sounds a whole lot off. What is your source of KNO3? Try dissolving a 1/4 tsp of that in a gallon of water and testing with your test kit.

[Aquafreak]

It's pure KNO3 from the pharmacy. It's pure white and very fine, dissolves instantly. It's 100% KNO3 as far as I'm concerned.

[djlen]

Aqua, what are you testing with? These results do not sound credible. Somethings not right. Are you using Salt Petre?
Len

[Aquafreak]

No I haven't been able to find salt petre, what I did find is something I suspect to be similar, it's pure white and readily dissolves when dosed. It just says Potassium Nitrate on the bottle. The chemist told me this is pure KNO3. And thats what I've been dosing with. Gonna try testing it again with a gallon juice bottle of tap water. I use Aquasonic Nitrate test kit btw.

[Aquafreak]

Just finished testing with the juice bottle with 1/4 tsp and nitrate came up about 1 or 2 ppm. hmmm

[inxs]

Try letting it sit overnight - a lot of tests(especially iron and lowrange nitrate) are slow to develope.

You might also try concentrating the test by using half the amount of testwater .

[Aquafreak]

ok the test kit I have isn't giving correct readings, I did a 90% water change, added 1/4 tsp KNO3 and tested with a different test kit and all is well. I hate cheap test kits.

[plantbrain]

Somethings wrong with your test kit. NO3 test kits have problems at 0-20ppm range with good accuracy.

I would not trust your kit.
I would trust knowing what the source water has to begin with, call the water company and ask, and dosing roughly 1/4 teaspoon per 33 gallons will give you about 5.5ppm of NO3 and about 3.5ppm or so of K.

If the kit is off by 1 ppm or so, then that's fine. But 2-4+ppm is not. Yours sounds much more than this.

It's relative unlikely for your plants to use 5.5ppm in one day. Even a healthy tank with everything and loads of light etc, will only consume this perhaps in 2 days.

Dosing 1/4 teaspoon 3x a week, maybe 4X if the last dose is right before the water change should more than supply the tank's N needs. Note: this doesn't include any fish/critter waste sources either.
You can dose higher, maybe 1/3 or 1/2 teaspoon 2-3x a week.

But 7 tsp means 150ppm of NO3, maybe a 30 day supply of NO3, no way the tank would use this before your next water change.

Speaking of which, you might want to do a 50% weekly and try the above routine of 3x a week with 1/3 to 1/2 teaspoon if your fish load is light.

Even with fast growers and high light, it's going to be very difficult to run out of NO3. It won't matter what the test kits say iof the tap doesn't have much NO3 and the KNO3 you have is pure.
If you add X amount(in grams) to the water, you will have a certain amount of mg/l. That is how chemical known reference solutions are made(pH, NO3, Ca etc).
This method bypasses the test kit and goes directly to the reference solution and guesses a little midweek etc...but this is pretty close and accurate for the plants and uptake rates. The 50% weekly water change make sure nothing builds up.

Regards,
Tom Barr

[Aquafreak]

Tom;
Should I check up on the nitrate and phosphates daily? Or should I play by the ear and dose it 2-3X week? I've started to get green dust algae lately, is there a way to prevent that type of algae? I just did a water change today, turned off the filter, elbow greased the algae good, waited 10 mins for it to settle then did a 90% water change and added ferts back, 3 tsps of flourish equilibrium, 1/4 tsp epsom salt, 1/4 tsp KNO3, 4 drops fleet, 7mls flourish and a tsp of EDTA Fe powder. I have a feeling this algae is gonna come back by the end of this week, I've had this type of algae a few years back and it kept coming back till I reduced the lighting.

[inxs]

Well Aquafreak and Plantbrain I had a 125 running last year with 3+ wpg cf lighting and compressed CO2 that was going through 6-10ppm of NO3 per day - tested on a new Saliferts kit that I callibrated w sourcewater and straigt KNO3 dissolved in water to make sure I got accurate readings I also did the testing at night and read results in the morning - I did a lot of testing in order to determine the NO3 consumption so I feel it was accurate.

My point is that 5-10ppm consumption per day isn't impossible in a high tech/light tank.

However 150ppm/day may be a little off:D

[Aquafreak]

I have over 5 wpg on that tank, but I think maybe just mayber my tank couldn't use 7tsps of KNO3 per day.

[plantbrain]

3-4ppm a day of NO3 uptake is reasonable, much more than this is becoming questionable. You should suspect your kit when you it's above 5-6ppm generally. Lamott's are good and I've measured some high daily uptake rates when I first add some KNO3 to a tank that's semi starved(plants not stunted but awful hungry).
But the mass of N to plant mass means that the plants/the tank had to assimilate close ~300 grams of dry weight plant in one day:-)
That would mean a couple of kilo's a week of dry weight or 12-15kilo's or wet weight plants. 7 tsp would fed a 300+ gallon tank for a week.

Something doesn't add up well there with a 33 gallon tank.

Regards,
Tom Barr