Switching from Flourish Nitrogen to Dry Ferts

[LightingBamboozled]

So I've been using up a bottle of Flourish Nitrogen bought before I knew better as my main source of Nitrogen. The tank is a 250L moderately planted, fish heavy tank with inert substrate. I dose approx 1-2ml of Flourish Nitrogen daily. The other ferts I dose are 1/32 tsp of a Monopotassium Phosphate and 4-6ml of CSM+B trace made up per directions daily as well.

Flourish Nitrogen is Potassium Nitrate and Urea. Am I likely to see any change in growth and health of the plants if I switch to dry dosing just dry KNO3 rather than a mix with Urea as a nitrogen source? Also any advice on working out what weight/vlume of dry powder is equivalent or am I alright to just start low and dial it up until it looks good?

 

[Zeus.]

You could always get some urea prills and do a mix yourself, urea prills are cheap and go a long way. Not 100% sure what the dosing NO3ppm level of Flourish Nitrogen is when dosed at recommended levels.
It would be pretty easy to do a Potassium Nitrate and Urea mix in solution and just add a few ml as before

 

[dw1305]

Hi all,

Flourish Nitrogen is Potassium Nitrate and Urea. Am I likely to see any change in growth and health of the plants if I switch to dry dosing just dry KNO3 rather than a mix with Urea as a nitrogen source?

You will add a lot more potassium (K) with potassium nitrate (KNO3) on its own. This is because urea (CO(NH2)2) <"just supplies nitrogen">.

It would be pretty easy to do a Potassium Nitrate and Urea mix in solution and just add a few ml as before

That would work, or you could use a horticultural fertiliser.

I'm using <"Solufeed 2 : 1 : 4">. Have a look at <"Solufeed 2:1:4 and Solufeed Sodium Free TEC Combination">.

cheers Darrel

 

[John q]

I dose approx 1-2ml of Flourish Nitrogen daily

Also any advice on working out what weight/vlume of dry powder is equivalent

1ml of Flourish Nitrogen in 250L of water = 0.06 N & 0.07 K.
If you went down the KNO3 & Urea route and added to 500ml of water ~ 23.48g KNO3 & 8g Urea each 1ml dose in your 250L tank would yield.
N 0.06
K 0.07

Or in layman's terms the same as Flourish Nitrogen.

 

[Zeus.]

1ml of Flourish Nitrogen in 250L of water = 0.06 N & 0.07 K.
If you went down the KNO3 & Urea route and added to 500ml of water ~ 23.48g KNO3 & 8g Urea each 1ml dose in your 250L tank would yield.
N 0.06
K 0.07

Just a quick double check and less than £1.00 per litre

 

[John q]

Just a quick double check and less than £1.00 per litre

Thanks zeus, I'd hurriedly done the calcs at work whilst pretending to sort the work schedule out. Always good to double check.

£1 a litre... Seachem retail 500ml for £17, must be the fancy bottles that bump the price up 😆

 

[LightingBamboozled]

You could always get some urea prills and do a mix yourself, urea prills are cheap and go a long way.

Yeah, I was hoping to move away from Urea, my pH being as high as it is and Urea breaking down to ammonia it's a risk waiting to happen for the fish.

You will add a lot more potassium (K) with potassium nitrate (KNO3) on its own. This is because urea (CO(NH2)2) <"just supplies nitrogen">.

Yeah, with this light dosing I was a little concerned about excess potassium obstructing calcium uptake but wasn't sure if I was excercising an abundance of caution. I could always use a mix of Potassium, magnesium and calcium nitrates to avoid excess potassium.

If you went down the KNO3 & Urea route and added to 500ml of water ~ 23.48g KNO3 & 8g Urea each 1ml

Doing it dry then, That's 0.047g KNO3 per daily dose (given 1-2ml that could be doubled to 0.094g) or 0.329-0.657g per week. KNO3 is about 10.4g/tsp meaning 1 or 2 1/32 tsp per week for the KNO3 half (0.325-0.650g). And by similar calculation I could replace the Urea with the same volume of Calcium Nitrate (0.385g - 0.770g) and half of Magnesium Nitrate (0.354g)

Although having done those numbers I think I might be slightly overdosing the potassium phosphate, It's getting the equivalent of 2.52g per week. (2.9ppm Potassium and 7.04ppm PO4 [2.3ppm P])

 

[Zeus.]

Yeah, I was hoping to move away from Urea, my pH being as high as it is and Urea breaking down to ammonia it's a risk waiting to happen for the fish.

For the level of Urea your dosing I see it being a problem, its not even 1 ppm NO3. I was dosing urea at much higher weekly levels but was doing little and often, worked out about 100times a week on a custom auto doser.

I was a little concerned about excess potassium obstructing calcium uptake but wasn't sure if I was excercising an abundance of caution. I could always use a mix of Potassium, magnesium and calcium nitrates to avoid excess potassium.

Well I have never heard of anyone posting a issue which was Calcium deficiency related. Plus your tap water probably has plenty of K already, don't think the water company's need to report on the K levels in there water reports- so they don't.

Doing it dry then, That's 0.047g KNO3 per daily dose

Dry dosing works best with nice easy masses of salts, IMO starting at 5 to 10 grams ( one to two teaspoons) When your dosing levels require such small masses 0.047grams they is a higher change of making errors. Much better to make a solution when your adding a at least 5 to 10 grams of a salt minimum, then just dose a least 5 to 10ml per time.

I think I might be slightly overdosing the potassium phosphate, It's getting the equivalent of 2.52g per week. (2.9ppm Potassium and 7.04ppm PO4 [2.3ppm P])

For the level of N your dosing the P level does seem a bit excessive as its at EI levels. As for your concern about the K levels I was never worried about K levels being to high.

Another general tip is to not make fert solutions that last too long. 4 to 6 weeks is ideal in a perfect world, as unless the ferts are made in laboratory conditions the solutions will have spores in it etc which has a higher tendency of being a nice broth for them to multiply in. The longer the fert solution is standing once opened the greater the chances and greater still with DIY fert solutions, yes we can acidify them which helps, but having several litres of fert solution with mold in is a PITA and a waste of ferts.

Dry doing works best in big tanks with EI dosing levels, pre loading ferts after a WC and remineralising RO water

 

[LightingBamboozled]

your tap water probably has plenty of K already, don't think the water company's need to report on the K levels in there water reports- so they don't.

Yeah, I was never worried about low K, but it comes along with the phosphate which I did need to increase. This 2013 thread on the forum has a good discussion of the potential issues with excess K. There are others.

Dry dosing works best with nice easy masses of salts, IMO starting at 5 to 10 grams ( one to two teaspoons) When your dosing levels require such small masses 0.047grams they is a higher change of making errors.

I have tools for reasonably accurately dosing volumes of dry salts down to 64th of a teaspoon (Sadly an American unit so it doesn't operate in mm3). I'm happy dry dosing. I would rather not have bottles of liquid fertiliser made up where possible.

For the level of N your dosing the P level does seem a bit excessive as its at EI levels.

Yeah, I might roll back the phosphate slowly to see if I can get away with dosing less.

 

[dw1305]

Hi all,

For the level of Urea your dosing I see it being a problem, its not even 1 ppm NO3. I was dosing urea at much higher weekly levels but was doing little and often, worked out about 100times a week on a custom auto doser.

I'm pretty sure it isn't an issue.

Well I have never heard of anyone posting a issue which was Calcium deficiency related.

You would need very soft water before calcium (Ca) deficiency became a problem.

Dry dosing works best with nice easy masses of salts, IMO starting at 5 to 10 grams ( one to two teaspoons) When your dosing levels require such small masses 0.047grams they is a higher change of making errors. Much better to make a solution when your adding a at least 5 to 10 grams of a salt minimum, then just dose a least 5 to 10ml per time.

<"Serial dilution"> fan as well, although I'll be honest <"I usually don't weigh the salts">.

Plus your tap water probably has plenty of K already, don't think the water company's need to report on the K levels in there water reports- so they don't.

They don't, which is ridiculous really, as it is about the easiest metal to test for using Atomic absorption spectroscopy etc. (potassium burns with a purple flame)

cheers Darrel