# Still blocked by K



## kekon (Aug 1, 2005)

As I wrote in previous threads I have many issues concerning potassium. I haven't solved the problem yet. I know and believe it's possible to keep high K levels with no issues but it doesnt work in my tank.
Each time K level is only 10 ppm or low, my plants are severely burned, deformed and tips are stunted. The total growth of most plants is very slow. If K is only about a few ppm, things go better but Cardamine Lyrata and Polysperma show K deficiency. I thought it was Ca deficiency and reconstituted RO water using baking soda and CaCl2 but it didn't help at all. Later I thought that high Cl and Na levels might have harmed my plants. Recently I've lowered Cl and Na levels to 5 and 2ppm respectively but one has to wait at least a week to see the effects. (about 3 weeks ago I had 35 ppm Cl and over 12 ppm Na). I know that there is certain element that is missing in my ferts that is blocked by K or, it exists in very small amounts too low for the plants. A man I know mixes RO water with tap one in 1:1 ratio (he uses TMG as opposed to me) and has the same Ca and Mg levels and he doesn't notice any issues having K of 15..18 ppm. 

my water parameters:

NO3: 10
PO4: 1
Ca: 24..30
Mg: 5..8
KH: 3..4
pH: 6.6


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## Avalon (Mar 7, 2005)

Why are you using RO water? What's wrong with your plain 'ol tap water?

Aside from that, I'd be willing to bet your CO2 levels are low. TMG is not your problem. K is not your problem.


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## Salt (Apr 5, 2005)

What's with all the RO hate? I seem to see it a lot...


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## kekon (Aug 1, 2005)

I'm in a favour of using only RO water because it gives me the great opportunity to control all the elements. Besides, tap water parameters are not stable and change in time. The only parameters I know are Ca and Mg levels and nothing else. I had very good results with only RO water but I messed something up with fertilizers.
A few months ago I used also RO water together with commercial NPK fertilizer which consisted N in urea form and (as producer declares) - biostimulators. Thing went very good with the fertilizer but I couldn't stop algae growth. I stopped using the NPK fertilizer due to algae outbreaks caused probably by urea existing in the fertilizer. So I switched to KNO3 and KH2PO4. At the same time I decreased the daily trace dosage to 25% of the recommended dose. Now I see that my problems are probably caused by too little traces so I've started today to increase the daily trace dose. The sign on that may be Didiplis Diandra which tops are rather green (at not high NO3 which is 10 ppm; the NO3 test kit was calibrated)


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## BryceM (Nov 6, 2005)

It seems that many people find that reconstituting RO water can be a bit tricky. I suspect that most of the problem is figuring out the right recipe that doesn't leave a nutrient in short supply. Trying to reconstitute RO introduces a large number of variables. If you are adding and testing for 5 or 10 different chemicals there are many opportunities for error. This can happen in the math, measurement, actual composition of the dry chems, test kit error, and how well your particular RO unit is running.

There are plenty of people using RO with great results, so it can clearly be done. It probably just takes a bit of trial & error to get it right.

I suspect Kekon that you're problem isn't K, but something else. I'd be inclined to start by looking at the Ca/Mg ratio. How confident are you in your numbers? Do you mix tap with RO? If not, why? Your Na & Cl levels don't seem high enough to warrant concern, even at 35/12.

One last comment. When adding new species to my tank it often seems that they don't do much for a couple of weeks. Then suddenly they seem to take off with rapid growth. My personal theory is that it takes them a few days to acclimate to the water chemistry. If you are making major changes to the water every week or so it might be hard for the aquarium to get settled in. Why not determine a recipe that you think is optimum and let it go for a month or so to see how things do? I think that would help you narrow down any actual deficiencies since you'd have a longer period to make observations. Stability counts for a lot.


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## kekon (Aug 1, 2005)

To reconstitute RO I calculate all the amounts of salts using Fertilator and precise scale. I know I changed some parameters too often and it was my mistake. You're right that it takes some time for many plants to acclimate. 
Now plants seem do grow better because I try to keep RO water parameters to be the same all the time. As far as Ca/Mg ratio I was told to keep Ca at 20..30 ppm and Mg at 5 ppm. In my country, one can buy a special fertilizers set especially designed to use only RO water. There are 4 bottles. First bottle contains mixture used to reconstiture RO water. Unfortunately there is too little Ca as it is only 13ppm (if recommended doses are used) and Mg 4 ppm.


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## Avalon (Mar 7, 2005)

I'm not trying to knock the RO thing. I have a tank that I use RO with to grow a specific few plants. I have found most anything can be grown in hard water. In my RO tank, I cut it with tap water to raise the KH to about 3-5 degrees. My original tap is over 22 dGH (the GH consists of lots of Ca & Mg, not one or the other), so I know I'm getting enough calcium--plants don't use that much Ca. I have found however, I have to add Mg via Epsom salts. Aside from lean dosings of KNO3, KH2PO4, K2SO4, Traces, and Iron, I haven't had any problems. I've noticed a lot of talk about nutrient ratios and stuff, but I'm unsure why. Just give the plants what they need and they'll grow. I'm going to try out Barr's GH booster and see how that works. My RO tank is an experimental tank of sorts, but so far so good. But why don't I use RO on all my tanks? Too much trouble and it's not necessary.


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## kekon (Aug 1, 2005)

The problem with my tap water is that it's difficult to know concentrations of other elements besides Ca & Mg. The only thing I can test myself is NO3 which equals to 10 ppm (using calibrated JBL test). In the summer (especially after it was raining) NO3 raises to 20 ppm or higher. Anyway, I'm going to buy TMG fertilizer.


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