Ph is 7.6 when co2 starts to 6.4 when it closes.Hi @nanomania
I took your picture, enlarged it, and this is what I saw
If we look closely we can see the newest leaves (at the arrow) are showing darker veins and lighter interveinal areas.....this is known as interveinal chlorosis. When it happens in older leaves the most common cause is insufficient available magnesium (Mg) however when it happens in newly emerged leaves the likely cause is insufficient available iron. Insufficient iron can be caused by a) not enough iron in the substrate or being dosed as a supplement or b) the wrong type of iron being dosed for the pH of the tank. pH prevents some types of iron from becoming available to plants for uptake. I see you are dosing Tropica Premium at 2X the suggested dose but what is the pH of your tank? -Roy
Thank you for replying in somuch detail. However DTPA10% POWDER is available, can i use that?Hi @nanomania
The most common type of iron used in fertilizers (because it is the least expensive) is EDTA chelated iron. EDTA chelated iron works fine if the pH of a tank is less than 6.2. However, when the pH of a tank is above 6.2 the availability to the plants drops off quickly (see graph)
At a pH of 7.6 very, very little of the ETDA chelated iron is available and even at a pH 6.4 probably only 75% of the iron in the mix is available. What I would suggest is picking up a bottle of Seachem Flourish Iron which is made from ferrous gluconate and is much easier for plants to absorb even at higher levels of pH. Dose per the instructions once a week to start. For the next four (4) watch the new leaves as they emerge, do they look greener, healthier, has the interveinal chlorosis diminished or subsided altogether? (Do not watch any existing leaves, typically they will not improve.) If after four weeks the problem is resolved great! If there still seems to be some interveinal chlorosis increase the dosage and watch for another four weeks.
Let us know how things progress, I hope this helps! -Roy
Thank you for replying in somuch detail. However DTPA10% POWDER is available, can i use that?
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