Some Plants Turning Yellowish

[ehlim]

My nanas and E Bleheri are turning yellowish. But other plants like H. Difformis, H. Polysperma. H. Corymbosa, Combobas, Amazon Swords, Vallisneria are doing well. W/c is 30% every week and 216 watts of lights for 9 hour daily. 20ml of Ferka is added into the 4x2x2 tank weekly. The water parameter checks conducted are as follows:

Ammonia = 0, Ph= 6.6, Kh= 4, CO2= 30ppm, Nitrite= <0.3

What is happening? Must I add additional supplements?
Another Q, I read in previous threads that the plants started "pearling" with 30ppm CO2. My do not. Pls advise. Tks.

[diki]

IMHO, nanas generally do not require too much light. Might be shining too much light on them? Maybe plant/put them below some stem plants to provide some shade for them.

BTW, you did not mention the temp of your tank. With 216w lights, doesn't that increase the water temp to quite high? Are u using a fan? Might be also due to high temp. Plants grow better at lower temp for most of them (try 26-28 if I'm not wrong).

[ehlim]

I doubt too much light is the cause of problem. Some of my stem plants tend to grow to the water surface and thus reduce the amount of light reaching some of the lower plants, such as, the nanas. On the contrary, I thought this could be a cause of the "yellowing". I do not use a fan, at least not till the hotter months. The tank temp hovers between 27 and 28. Cheers.

[diki]

Hmm...

It might be a case of nutrient deficiency that cause this problem from what I have read in some website. Maybe u can post a picture of your tank so other bros can better advice u. Also are the new leaves turning yellow or yellow at the edges? Is 20ml of Ferka the recommended dosage for a 4 ft tank? If too heavily planted and u got fast growing plants, might need to add more frequent. Just my thought. Maybe other bros can advice.

[PeterGwee]

Ferka has an entire line which is required to work well. Which exact ferka product are you actually using since most trace-mix like the Aquatilizer does not contain NO3 nor PO4.

Regards
Peter Gwee

[ehlim]

The whole leaf is "yellowing" and not just the edges. I am using just the Aquatilizer and nothing else, save for 10 caps of Nutrafin Cycle for every change of water. What will be the recommended nutrients I need to add to aid plant growth? Btw my tank is only 1.5 months old and the substrate is made up of JBL fertiliser and base sand. Tks.

[|squee|]

I believe you need to couple Aquatilizer with Balance-K. The Ferka substrate fertilisers (Rosetta) will do good for your Echinodorus. Keep CO2 good as well, it's the fundamental root of all problems.