sparse rotala green leaves

[anzai]

i have encountered some minor problems in my tank ...

firstly my rotala green is quite sparse.
it has grown very fast, however the intervals between each node of 2 leaves is quite far apart, so i have failed to achieve the bushy look ...the stems of the plants are also quite thin. i dont test for parameters but

basically i keep a 2 ft tank (15 gal) with 55W light, about 1 bps co2 and occasional dosing of tmg...

more symptoms that my tank faces are black hair algae that grows everywhere ... and the leaves of the rotala often have black or brown spots, which i suspect is from nutrient deficiencies ... but which nutrient i know not?

basically thats about it ... i will try to post pictures to show what im trying to say ...

any remedies guys?

[chua]

Seem to me that you have sufficient light and CO2.

But TMG does not contain the two important macro nutrients which is NO3 and PO4.
With these limiting factors, algae may thrieve.

[Plantbrain]

This plant needs good NO3 to do well over the long term.
Regards,
Tom Barr

[anzai]

ok ... thanks for the help ...
that means more fishies .. .muahahaha

[bclee]

[quote:daf55ebd3b="anzai"]ok ... thanks for the help ...
that means more fishies .. .muahahaha [/quote:daf55ebd3b]

WRONG! Adding fishes gives you NH3. A potential problem for algae.

Add KNO3 instead.

BC

[anzai]

hmm ... in the long run ... the nitrogen cycle will reduce ammonia to nitrites to nitrates right?

anyway i will pmdd kno3 ...thanks for the advice

[Plantbrain]

As long as you have a moderate fish load, this holds true, but if you add lots, then you will run into algae issues. I add about 1.5-2x the normal amount of KNO3 and dose it separately from an all in one mix like PMDD.

So a 20 gal tank will get 1/4 teaspoon of KNO3 every other day and then a 60% water change each week. You might be able to get away with less if you have a good sized fish load.

You can get a fair amount of NO3 from fish, but most will be removed as NH4 first by plants and if there's enough NH4, algae also. Otherwise we could just keep adding fish to supply the plants, but it does not work that way.

NH4 from fish waste is harder to measure and quantify, while KNO3 is not.

The problem is that NH4 is removed as fast as it's produced. If not, say there's too many fish, then this NH4 will back up and become available to algae and cause a bloom.
You do not want this to happen ever so we error on the KNO3 side of things mainly. Fish are happier with less bioload also.

For this tank, I'd add about 1/4 teaspoon of KNO3 about 3x a week with a decent fish load. TMG abou8t 3-4x aweek at 3-4mls each dose. A little KH2PO4 and that's about it along with CO2 in the 2-0-30ppm range for the entire light period.

10 gal water change each week.
Repeat

Regards,
Tom Barr