Phosphate/Nitrate dosing

Henrik

Member
Joined
16 Nov 2008
Messages
67
Location
Chester, Cheshire
As a newbie to this forum, I am experiencing severe information overload at the moment...After I first read about EI yesterday, I have scanned through many threads on dosing and read the relevant articles - but I cannot seem to find a simple rule on how much Nitrate/Phosphate you should dose on different sizes of tank with different light levels. At the moment I have EasyLife Fosfo and Nitro at my disposal but have not used it yet.

I am at less than half a watt per litre, which I guess is a low or medium light level, and the effective illuminated tank size is about 280l including the substrate (45l or so behind decorative Back-to-Nature background used as a filter, no light). I am sure the information is somewhere, can somebody just point me to it, please?

Another small question - do 'normal' fertilisers (like ProFito) play the role of the often quoted 'trace mix' if you are not yet into DIY fertilisers?

THANKS!

Henrik
 

George Farmer

Founder
Staff member
Joined
30 Jun 2007
Messages
7,068
Location
Cambridgeshire
Welcome along, Henrik!

Personally I'd simply follow the instructions on the Easy Life bottles, but consider dividing up the weekly dosing into daily doses. If you experience nutrient deficiencies then add more.

Profito is trace, yes. It also has Potassium and Magnesium.

All the best.
 

Themuleous

Member
Joined
6 Jul 2007
Messages
4,124
Location
Aston, Oxfordshire
Henrik said:
but I cannot seem to find a simple rule on how much Nitrate/Phosphate you should dose on different sizes of tank with different light levels.
That is the tricky thing, there is no one rule to fit all tanks, unfortunately! The EI method works well as it just provides the plants with more than they need of everything and in doing so eliminates the guessing part fert dosing, which is why it works so well on any tank.

Sam
 

plantbrain

Expert
Joined
2 Aug 2007
Messages
1,946
Here's a graph:
Macro_Growth_Curve_Adjusted.jpg


EI targets the 90% yield region on this graph.
If you reduce the light, this yield will decrease obviously.
If you remove the CO2, the yield will drop by about a factor 10-20X.
So while you have less demand, you still have ample wiggle room in concentration, even if you have less light/less yield.

The outer limits are quite large, I've never found them for plants, but know they are beyond 150ppm for shrimps. Plants like can go to 300ppm or perhaps more for NO3.

Still, hitting a range of say 20ppm is pretty easy to do and keeping it there.
Note, EI is not a formulation of a particular ppm, just a basic concept to dose a target range.
The range itself is not suppose to precise, that 90% range is pretty big.

For ppm's and ranges, this was done long before EI got as popular, around 1995-1996 here in the USA.
We did an article some time ago for that and it really has not changed much since except folks are less scared of PO4, see "list of levels and parameters for planted tanks" on my site.

There's no claim that EI is rigid anywhere, you can reduce it, modify it, dose daily, dose 2-3x a week, etc, you can remove the KNO3 and add K2SO4 if the tap water you use has high NO3 etc and so forth. Common sense, not a cook book approach applies and should with any aspect in the hobby.

I prefer hobbyists get a good foundation how to figure things out for themselves and use their noggins, some want you have faith in them, or their products/buy their products, I'd rather see you think for yourself. I think a better educated hobbyists that can look at things critically is better able to help others in the hobby as well.
Otherwise this turns into a religious thing, not one based on Science/logic.

If you suspect something, test, but also confirm that the test was good/valid.
Do not assume that a 10$ cheapo test kit is accurate, do not assume a theory is correct if you see falsifying examples that it cannot be.

Confirm that it is.
Maybe all that is not your game, you just want plants etc, still, you can look and see what is really the deal based on the evidence and approach. Fear the ones blowing the hot air and asking for $;) Just getting folks to take care of the aquarium regularly is about the hardest thing.So whatever does that is good, there's the human social factor in there also.

Regards,
Tom Barr
 

Henrik

Member
Joined
16 Nov 2008
Messages
67
Location
Chester, Cheshire
Thanks for the replies - what I know now is that it is up to me to find out how much my plants need...

Can somebody recommend exactly what dry ferts to buy, and from where, for a 325l tank (~280l illuminated, 2x54W T5 with reflectors)- I think I can figure out a dosing regime from there, which I will post anyway to get a few opinions from the 'pro's.

I still have quite a supply of Dennerle V30 Universal fertiliser and E15 iron tablets, can I use this in place of something until it runs out? I will also use up my bottle of ProFito until I start with self-mixed traces...

I have read different views on whether EasyCarbo is helpful/required (I have a pressurised CO2 system). What is the latest view on this?

Thanks a lot for the great help,

Henrik
 

JamesC

Member
Joined
3 Jul 2007
Messages
1,276
Location
Bexley, Kent
I still think that with nitrate dosing here in the UK we have to be slightly careful. Many people have 40+ppm nitrate in their tap water. Add to this dosing double or higher Estimative Index and also nitrate produced as a direct result of fish, etc in the tank can lead to way excessive levels. Adding 20ppm NO3 3x a week and 50% water changes results in a level of 120ppm. Add to this the 40ppm from the tap and some more from the fish and you have 150+ppm levels. Yes plants will use some but not make that much of a dent unless you have a fast growing jungle with a masive lighting rig.

Tom Barr wrote a while ago that he found shrimp died at levels of 120ppm nitrate. Now in my book having nitrate at those levels is very bad if it can kill shrimp. Levels of 15 to 30ppm are what we should be aiming for.

Just my thoughts.
James
 

Henrik

Member
Joined
16 Nov 2008
Messages
67
Location
Chester, Cheshire
Add to this the 40ppm from the tap and some more from the fish and you have 150+ppm levels.
Now I am confused. Tom wrote in a different thread that the impact of fish and bacteria on the NO3/PO4 levels was quite irrelevant, unless you had a very heavily populated tank. Did I misunderstand something?

I checked the nitrate levels in my tap water with my water company, here in Chester they are supposed to be around the 10ppm mark, with PO4 at 1.5ppm. I will verify with a standard test kit, despite their inaccuracy...

If somebody could point me to the dry salts I should be getting, I would be grateful. Do they go off at all?

Thanks, Henrik
 

aaronnorth

Member
Joined
19 Feb 2008
Messages
3,953
Location
worksop, nottinghamshire
Potassium Nitrate - 40g to 500ml of water and adding 10ml per 100L of water would give you a value of 5ppm.
Potassium Phosphate - 15g to 500ml of water and adding 5ml per 100L of water would give you a value of 1ppm.
Trace mix - 15g to 250ml of water will give you about the same concentration as off the shelf products
 

plantbrain

Expert
Joined
2 Aug 2007
Messages
1,946
In general, if you have 40ppm of NO3 in the tap water (make sure this isNO3, not N-NO3-you need to convert that to ppms of NO3, not N, so 4.4X that ppm amount), there is no need need to dose KNO3, switch to K2SO4 instead.

Dose about the sme amount of K2SO4 as the suggestion for KNO3.
Do 50-70% weekly water changes.

This will add all the NO3 required for most tanks.
Realize also that the NO3 from tap does/can change as well.

While 150ppm will not harm most things, you still wnat no more than about 30ppm or so, 10 is a on the lower end, so anything between 5-10ppm on thre lower end with lower light to 30ppm on the upper ranges isfine.

Use EI and water changes, tap ppm of NO3 to target that for your light/CO2 set up.

Regards,
Tom Barr
 

Henrik

Member
Joined
16 Nov 2008
Messages
67
Location
Chester, Cheshire
Can I use Calcium Nitrate for Nitrate/Calcium dosing? I have just been looking up what the feed I use for growing hydroponic tomatoes in the summer is made of, I thought that if I started mixing my own aquarium ferts, I could stop ordering 5l canisters of hydroponic feed and mix it myself as well...Anyway, one of the feeds is 100g/litre Calcium Nitrate, providing 15.5% Nitrogen and 19.5% Calcium.
 

plantbrain

Expert
Joined
2 Aug 2007
Messages
1,946
As James mentions but the GH build up is not that much, you might end up with say 20ppm added Ca and it would level off due to EI.

I'd add some Mg to go with it via Epsom salt.
I use a basic GH booster with good Ca/Mg/K+ all in one.

Then I can avoid any issues and use KNO3 as the NO3 source, or avoid it if the tap was high in N03.

You can play around with various salts to get whatever you want based on tap, fish load etc and apply EI with some common sense to your general goals.

Regards,
Tom Barr
 

Similar threads

Top