05-02-2013, 11:35 AM
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Originally Posted by OSagent23
I did have to start dosing some phosphorous and potassium in the aquarium. I am dosing very little at the moment. I'm noticing browning and yellowing of new growth. I read on it, a good friend also told me lack of those two nutrients as suggested on here as well. We will see in the next week or two what happenes.
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Be careful here. Phosphate should not have to be added to any aquarium with fish, as even with minimal feedings there will be more than enough for plants. The "average" aquarium can have phosphates in the range of 1 to 3 mg/liter (= ppm), while natural waters contain something in the region of 0.005 to 0.02 mg/l, which is certainly sufficient for plants. I've never used a phosphate test kit, so I've no idea how accurately they measure. But I do know that in more than 20 years I have never added phosphates and I certainly have no issues. My tap water is so nutrient-poor it is almost RO.
As for potassium, the amount in prepared fertilizers shoud be sufficient in natural (low-tech) systems. Now, I realize you are using diffused CO2 [I assume this is still running], but as i said previously (I think) changes have to be given time to work. It has only been less than one week since drastic changes were made (half the light, etc) and I would give the system 2-3 weeks minimum before jumping to conclusions. And everytime you start adding something else, you are throwing the balance off yet again. This is where alge has an advantage.
I wuld like to see a photo of the new leaf growth, as it may be something entirely different.