Intros

I believe we can better say that EI method works for some plants and not for others, since from informations above and other past similar threads we found that the effect of high nitrate has different results in some species, from high nitrate lovers (Blyxa japonica for example) to "low nitrate" plants.

Glouglou

I edit my last post. It was somewhat scrambled, the term PH was taking out by my spell checker and other modifications.

It will now, make more sens...

Sorry!

kekon

I think that the following routine may help to overcome problems with stunting, slow growth, pale leaves etc. (it works very well in my tank)

1. If NO3 is above 10 ppm try to lower it to max. 5..10 ppm (for very soft water GH = 2..5 try to
keep no more than 5 ppm; for harder water 10 ppm should be more than enough)
2. If you use KNO3 as the only source of NO3 and K add an extra dose of 10 ppm of K from K2SO4
or KHCO3. If K is deficient you should see improvement in plants growth in about 3..4 days.
3. If you notice that adding K doesn't help - add some more Mg (about 3..5 ppm). If Mg was
deficient you should see improvement in plants growth in about 3..4 days.
4. High NO3 or NH4 is the main cause of stunting especially in stem plants so don't dose too much ! (but don't keep NO3 and PO4 at 0 ppm - it will cause green dust algae).

Glouglou

I up my Mg from 9mg/l to around 15 mgl. Ca is 40 mgl (I personally think that Ca is rarely the culprit in bad Ca uptake, in my survey on 33 weeks it never went down 40 mg/l)

My ludwigia that was almost dead and crinckle have new growht almost perfect, she’s coming back to life, Elodea growing fast and nice. everything seem better. Some pearling even on the dead old ludwigia leaves. Even some java fern that was dormant for more then a year came back to life.
Not sure but Rotala indica is beautiful but seem to slow down a litle bit on growht. (less side roots)

I’m adding Potassium at 16.5mgl (as my survey show). This the only part that I cannot test, I just go with the flow.

I wonder the rate of potassium uptake in a well lit, co2 tank???

I want to lower my Fe (traces) to .2 to get a small amount of GSA, GDA at bay...

Another thing My phosphate seem to went up by itself, I need to look at number on this one...

Glouglou

Somebody know about a cheap good potassium test (I really like to know what’s in my tank)

The only one affordable is this one at 30 buck.

seem to be kind of home made kits....?

Or do we have any idea of the rate of potassium uptake in such and such condition, we need to know more about potassium...

detlef

Glouglou,

I've tested for K+ uptake several times and found rates of roughly about 0,5 - 0,9ppm/day for heavily planted tanks and 2-3 watts/g.

Try this e-mail drussup@mn-net.com to get a turbidity kit (tests for K+ up to 15ppm max.) from a German company called Macherey Ing. with a branch in the U.S. No idea about $$ though. I'm sure there are different other brands available for you as well.

Best regards,
Detlef

kekon

Once i wanted to purchase professional K+ test kit of VISOCOLOR series but the price was high: it was nearly the same as a price of Eheim 2217 canister filter. Finally i dropped the idea.

detlef

yes kekon, that's the one I was talking about before. It's now called Visocolor eco potassium sold over here in Germany at an amazingly high prize. There it resembles professional products but other than that I doubt...

Well, if you want to know what's going on in your tank and don't know some one working at a lab what else can you do?

Regards,
Detlef

kekon

Once i brought a water sample to chemists who work at a university where i was studying. They have a laboratory and some good equipment to carry out K+ measuremets as well as other elements (Na, Ca etc.). Also, i got to know it is possible to get to a laboratory at a sewage treatment plant in my town (however i've never chosen this option).
The other choice is an agricultural laboratory (where i made most measurements). They measure macro and micro nutrients in the water and in soils. Some of measurements may take a few days of time (especially in spring and summer because they have a plenty of work to do during this period)
There is one in my town where i made all the measurements concerning my tank (K, Ca, Mg, NO3) They do K+ measurements for a low price ($5 for one measurement). The problem is they work from 7 to 15 and but get back home at 15:30... To bring them samples of water from my tank i have to take a day off which is rarely possible...

Glouglou

Tanks detlef, for your answer

This answer give me a better appreciation of what I need to dose

— I was dosing 16.5 mg/ week
— .8 x 7 days = 5.6 mgl uptake
— Left in the tank 10.4 mgl / 28 gallons of water (.37 mg per gallon)
— with 4 liters RO water change without potassium
.37 x 4 = 1.2 mgl —> 10.4 - 1.2 = 9.2 mgl left

At 16.5 mgl/week I probably end up with to much potassium with the buildup.

I need to add 5.6 mgl + 1.2 mgl = 6.8 mgl / should be allright when start with the initial amount of K you need in concentration ( 15 to 30 ppm)