Dosing Question

Chrisjb330

Member
Joined
18 May 2020
Messages
38
Location
Nottinghamshire
Hi

Can anyone help me with this please;

Im using the Aquarium Plant Food UK kit, however due to there being PO4 and NO3 in the tap water along with the high fish load i havnt been dosing these.

Ive been dosing;

500ml Bottle, 50ml Dose alternate days with a rest day then 50% WC.

Macro

6 Tsp of Magnesium Sulphate
2 Tsp of K2S04 (from

Micro

1 Tsp of Cheleated Trace Elements


2 Weeks ago i took a lot of fish back to the LFS to reduce the bioload, ive since been testing my water on the water change day. Nitrates 40-80 and Phosphate 2ppm.

I have asked the lab at work to test my water (full results next week) but they have said that my Nitrates are 17ppm. (Test kit obviously wrong)

So should i be adding some NO3, im thinking no if there is 17ppm still left on wc day?



Im also confused by the calculator as the results will say a target of eg 7.5ppm of K, but isnt the target 30ppm a week?

1604155353143.png


Ive also tried the cheleated trace but it doesn't add with the instructions from Here which says 1 tsp

1604155478059.png
 

dw1305

Expert
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7 Apr 2008
Messages
10,966
Location
nr Bath
Hi all,
I have asked the lab at work to test my water (full results next week) but they have said that my Nitrates are 17ppm. (Test kit obviously wrong)

So should i be adding some NO3, im thinking no if there is 17ppm still left on wc day?
Can you find out how they've reported the NO3 level? Sometimes it is quoted as the ppm of nitrogen (N) contained in the nitrate (NO3-), in which case the the 17ppm N would be pretty close to the 60 - 80 ppm NO3. There is a more detailed answer in <"Which NO3......">.

Having said that unfortunately home nitrate (NO3-) testing <"isn't straightforward">, mainly because all nitrate salts are soluble, which means you have to <"reduce"> the NO3- (to nitrite (NO2-)) before you can form a coloured, insoluble salt that you can measure by colour change (colorimetry).
Im also confused by the calculator as the results will say a target of eg 7.5ppm of K, but isnt the target 30ppm a week?
Because of the difficulties in accurately testing (for a <"lot of the factors we are interested in">) techniques have been developed that do away with the need for extensive water testing. <"Estimative Index (EI)"> (this target) was designed so that plant growth is never limited by a shortage of mineral nutrients, and offers the potential for optimal plant growth, in CO2 enhanced high tech. situations.

The <"Duckweed Index"> use the growth, <"and leaf colour">, of a floating plant as an indication of when to add nutrients. It is mainly aimed at people who keep low tech tanks and <"use their plants as a mechanism for maintaining water quality">, plant growth will rarely be optimal and the aim is just to have some plant growth.
Ive also tried the cheleated trace but it doesn't add with the instructions from Here which says 1 tsp
They are the same amount really, a teaspoon is ~6g, so your 5.85g is <"much the same">.

cheers Darrel
 

Zeus.

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1 Oct 2016
Messages
3,378
Location
Yorkshire,UK
Nitrates 40-80 and Phosphate 2ppm

Cant see the NO3 being above 50ppm at thats the legal limit for water suppliers, as for the PO4 there is no limit.
I have asked the lab at work to test my water (full results next week) but they have said that my Nitrates are 17ppm.

So if the result is to be trusted, then with a 50% WC you will be adding 8.5ppm NO3- but the [NO3] in your tap water will vary over the year, I just use half the minimum value as we are not concerned about high NO3 levels.
7.5ppm of K, but isnt the target 30ppm a week?

it is if you read the small print
1604320138595.png


There isn't a 'magic' ppm for any element as long as you are dosing above the plants needs you will be good, watching your plants is the most important, spot a deficiency, diagnosis it, increase to relative elements dose, if the deficiency goes you nailed it, or what most do is just dose a bit more so everything is in excess
 

Chrisjb330

Member
Joined
18 May 2020
Messages
38
Location
Nottinghamshire
Thanks Darrel, ill ask about the Nitrate.

Cant see the NO3 being above 50ppm at thats the legal limit for water suppliers, as for the PO4 there is no limit.
Perhaps i wasn't clear. Those results were at the end of the week from the tank.

Tap water Nitrate is avg 17ppm (6-35)
Phosphate is approx 2 so little change after a week so i guess the plants are using as much as is created.
it is if you read the small print
4 x 7.5 = 30ppm o_O

The main reason i ask is that i have some contradicting results from growth. Mainly things look a bit yellow, Polysperma / Crypt has yellow edges with green middle on a few leaves.

Ive turned the light up this week as it was quite low.
 

Chrisjb330

Member
Joined
18 May 2020
Messages
38
Location
Nottinghamshire
Can you find out how they've reported the NO3 level? Sometimes it is quoted as the ppm of nitrogen (N) contained in the nitrate (NO3-), in which case the the 17ppm N would be pretty close to the 60 - 80 ppm NO3.
Asked today and its NO3, so the test kit is a bit off.
 

Chrisjb330

Member
Joined
18 May 2020
Messages
38
Location
Nottinghamshire
Im thinking i should half my K and Mg dosing.


Here is the water report from my area.

For most analysis, results are from samples taken at random in the water quality zone of your area. In some cases, results are from samples taken from water treatment supply points feeding the zone.
Hardness Values
AnalysisTypical ValueUK/EU LimitUnits
Hardness LevelHardNo standard applies
Hardness Clark17.43No standard appliesDegrees Clark
Hardness French24.91No standard appliesFrench Degrees
Hardness German13.95No standard appliesGerman Degrees
Data is for period 01-July-2019 to 30-June-2020
For most analysis, results are from samples taken at random in the water quality zone of your area. In some cases, results are from samples taken from water treatment supply points feeding the zone.
Water Quality Summary Report
AnalysisAnalysis UnitsNo of ResultsMinimum ResultAverage ResultMaximum ResultNo of results above PCV limitUK/EU Limit
1,2-Dichloroethaneµg/l32<0.09<0.20<0.3003.0
Aldrinµg/l8<0.001<0.002<0.00300.03
Aluminiumµg/l75<5<10300200.0
Ammoniummg/l75<0.015<0.039<0.06400.5
Antimonyµg/l8<0.08<0.170.3005.0
Arsenicµg/l80.170.701.55010.0
Benzeneµg/l32<0.04<0.08<0.1201.0
Benzo-3,4-Pyreneµg/l7<0.001<0.001<0.00100.01
Boronmg/l32<0.016<0.0280.03701.0
Bromateµg/l7<0.20<0.811.23010.0
Cadmiumµg/l8<0.03<0.060.1505.0
Chloridemg/l3217.3057.89119.800250.0
Chromiumµg/l8<0.2<0.62.1050.0
Clostridium perfringensNo. / 100ml7500000.0
Coliform BacteriaNo. / 100ml19700000.0
Colony Count After 72 Hours at 22ºCNo. / 100ml750166000No abnormal change
Colourmg/l Pt/Co75<0.40<1.584.17020.0
ConductivityµS/cm at 20ºC7529243761602500.0
Coppermg/l60.00220.02690.093902
Cyanideµg/l32<2<3<4050.0
Dieldrinµg/l8<0.003<0.006<0.00800.03
E. coliNo. / 100ml19700000.0
EnterococciNo. / 100ml800000.0
Fluoridemg/l80.430.510.6801.5
Free Chlorinemg/l197<0.02<0.140.470No abnormal change
Heptachlorµg/l8<0.001<0.002<0.00300.03
Heptachlor epoxideµg/l80.0000.0000.00000.03
Ironµg/l75<3<19770200.0
Leadµg/l6<0.2<0.30.4010
Manganeseµg/l75<0.2<0.83.5050.0
Mercuryµg/l33<0.005<0.010<0.01501.0
Nickelµg/l61.01.82.4020
Nitratemg/l85.9716.2435.30050.0
Nitritemg/l8<0.003<0.005<0.00600.5
Nitrite - Nitrate Calculated-80.120.330.710<1
OdourDilution Number750000Acceptable to Customer and no abnormal change
PAHµg/l70.000.000.0000.1
Pesticides Otherµg/l620<0.001<0.0070.02700.1
pHpH value747.317.638.080Min 6.5, Max 9.5
Seleniumµg/l8<0.21<0.410.65010.0
Sodiummg/l824.626.528.80200.0
Sulphatemg/l325367870250.0
TasteDilution Number750000Acceptable to Customer and no abnormal change
Tetrachloroethene and Trichloroetheneµg/l80.000.000.00010.0
Tetrachloromethaneµg/l8<0.06<0.13<0.1903.0
Total Organic Carbonmg/l32<0.4<1.12.70No abnormal change
Total Pesticidesµg/l310.0000.0110.07100.5
Total Trihalomethanesµg/l812.8934.1243.580100.0
TurbidityNTU75<0.06<0.150.4504.0
Key for units
mg/l
is equivalent to one part per million
μg/l
is equivalent to one part per billion
Dilution number
is a standard method for detecting taste and odour
mg/l Pt/Co
is a reference scale for assessing the clarity of the water
μS/cm
measures the natural mineral composition
Hardness Level
the three measures shown are the most common used by washing machine manufactures
Less than
means that this is the lowest value that the high quality equipment can measure
 

Zeus.

Member
Joined
1 Oct 2016
Messages
3,378
Location
Yorkshire,UK
Sorry seen this the other day and meant to reply, got caught up with other things.

I have Hard water as well I am sure it contains loads of potassium (K), yet I still add K which on one hand is silly, however as long as the K is in excess for the plants (up to certain levels) we have met the criteria for EI dosing. Trying to micro manage you waters parameters is hard as the tap/well water changes with the seasons, so I use the lower [elements] over the year in the water reports with my water company produce. In doing the fert calculator we are close to release, I did some research into water reports and what some water companies produce is very limited in detail. So some parts of the calculator had to be scrapped which gave kH and gH values of you tap water, as one shoe didn't fit all.
Which is why using RO water has a major advantage as it has nothing in it, you just add what you need/require and you know what you have. RO water can be expensive to buy/produce if you have a large tank. I am in the process of getting house with a bore hole for water so RO water for my tanks is on the cards.
The best advice is watch your plants, if they are growing well then all is good.

I personally would account for the values you have and keep an eye on the plants, they will tell you if they are not happy.
 

dw1305

Expert
Joined
7 Apr 2008
Messages
10,966
Location
nr Bath
Hi all,
Advice on how to proceed anyone?
Apologies as well.

The analysis on your water, done by the lab., will give you accurate values for that day. This is because it has used <"ICP/MS"> and spectrophotometry as analytical methods. However, "on the day" is relevant, because as @Zeus. noted, your water is quite variable, probably because it is a mixed water supply with varying amounts of surface (from a river/reservoir) and ground (from a borehole) water.
The best advice is watch your plants, if they are growing well then all is good.
The <"Duckweed Index"> use the growth, <"and leaf colour">, of a floating plant as an indication of when to add nutrients. It is mainly aimed at people who keep low tech tanks and <"use their plants as a mechanism for maintaining water quality">, plant growth will rarely be optimal and the aim is just to have some plant growth.
That one. If you want to stick with EI, I'd probably try 1/2 dosing (including the N and P) and monitor the <"TDS (conductivity value)"> to see if it is rising.

cheers Darrel
 

Chrisjb330

Member
Joined
18 May 2020
Messages
38
Location
Nottinghamshire
The best advice is watch your plants, if they are growing well then all is good.
This is whats prompted me to look into it a bit more as i have a few plant issues but dont know what im not sure what im lacking or have in excess.

That one. If you want to stick with EI, I'd probably try 1/2 dosing (including the N and P) and monitor the <"TDS (conductivity value)"> to see if it is rising.

I have too much surface movement for the duckweed :(

Including the Phosphate (2ppm from tap and end of the week) and Nitrate (17ppm at end of week)?

Which is why using RO water has a major advantage
I've thought about doing this for a while. The frustrating thing is that i can get pharmaceutical grade RO water from work, but taking 125 litres of it a week is a challenge and taking advantage a bit.

The other thing thats putting me off is that id need something to fill up which is relatively permanent, maybe a blue barrel. However it does have its advantages of being able to pump it out pre heated into the tank on WC day.
 

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