Proper levels of nitrate/phosphate

[Blinky]

The NPK fertilizer I bought mentions that frequent testing is important to know when to redose, and I'm not sure if there's an ideal level between the maximum (I believe it says not to go above 1ppm PO4 and 20ppm NO3) and zero - can someone give me an idea of what levels of nitrate and phosphate I should be aiming for?
I'm having problems with green water, and I want to make sure the plants have enough nutrients to grow well and out compete the algae, while not providing the algae with any extra nutrients.
I put a dose of the NPK in yesterday and it raised the nitrate to around 7ppm and the phosphate to 0.25ppm. This afternoon I tested both levels and they were down again (not 0, but almost not registering), so I added another dose to bring them back up to 5-7ppm and 0.25. Should I add another dose?
One more question, all the plants are putting out roots like crazy - every node has long roots, reaching out into the water and down towards the gravel. I was wondering if this is what usually happens, or is this a sign that my plants are seeking nutrition?
Thanks for the help

 

[djlen]

N=10 - 20 and P=1.0 - 1.5. K should be dosed according to your fish level.
In other words, many folks use 20ppm/K as a rule of thumb. For many applications this is not necessary. KNO3 contains plenty of K and with a light fish load, it and Fleet's Enema are all that is necessary when one keeps a low quantity of fish.
I suggest that when you run low on the all purpose food you are presently using, that you opt for individual nutrients. This will improve your flexibility in dosing.
Your plants are happy from the sounds of the feedback you report. They are also using your nutrients. This is good. The problem may be not enough of them(plants) in the tank.
Also, this is a fairly new set up, correct? If so, keep dosing and changing water and allow the tank to mature and the plants to take over.

Len

 

[Blinky]

Thanks so much for the reply
I will follow your advice. I've been reading like crazy, mostly from the Krib website, and discovered that sometimes plants produce red leaves due to a nutrient imbalance, not in response to light levels - lo and behold, I started adding NPK and guess what? Green leaves! If nothing else, these plants are giving me a crash course in chemistry