RinaLane said:
I looked up Seachem Flourish seems very reasonable 5ml for 60G & I have only 75G. Healthy plants worth this price. But reviews says it works micacles only on small tanks with low light otherwise i need to double doze is it true? Do I need also to add Seachem Excel? What about root tabs?
GH is 6.5-8 i coudnt find in report online anything about calcium or magnesium.
Responding to the last item first, the GH is fine. GH (general hardness) is primarily the calcium and magnesium. Most authorities suggest a GH of 4 dGH [= 70 ppm) minimum for sufficient of these minerals for plants, and I have found that to be accurate. I have near-zero GH (7 ppm or less than half a degree) and I raise it to 5 dGH or 6 dGH in the tanks with the larger swords. So you're OK here.
Root tabs will help larger swords (single plants), and some others. Obviously substrate tabs will have no benefit for plants not rooted in the substrate (like your Anubias, and any floating plants). The benefit of substrate tabs is that the nutrients are released over time and closest to the root systems, and they do not get into the water column the way liquid additives do directly. So for heavy-feeding plants rooted in the substrate, they will benefit. I use them next to my larger swords, aponogeton and red tiger lotus. For rapid runner plants, like the chain swords and Vallisneria I have not found them necessary.
Excel is a carbon supplement, so-called "liquid carbon." As I have written elsewhere, I do not recommend this product because it is a toxic chemical. But to your situation, it is known to kill Vallisneria outright, and you have Vallisneria. There will be sufficient CO2 occurring naturally to balance the light and other nutrients. I have never added any form of carbon in more than 25 years of planted tanks. CO2 does become necessary when you move into high-tech systems with intense lighting and daily nutrient dosing, and then a diffuser is best.
As for doubling the Flourish Comprehensive, sometimes this is helpful, sometimes not. I have had outbreaks of brush algae (what you have) solely from adding a second weekly dose, so one has to be careful. Down to that balance again. "Low light" is a subjective term, and it is always risky to generalize too much. I do use the terms low, moderate and bright for plant light requirements, recognizing these are subjective terms and only I really know what I mean by them without detailed explanations. Many will write that anything less than 2 watts of light per gallon is low light, but to me this is high (bright) light; none of my tanks have anywhere close to this. Not to mention using watts now days is deceptive as there is lighting that produces much more intense brightness with less energy, and watts is simply the amount of energy a bulb or tube uses to produce its light.
I would start off with once a week, and after a few weeks observe the plants' response, and algae. If the plants respond positively and algae does not, you will have found the balance. For a 75g, I would use one teaspoon (5 ml) of Flourish Comprehensive. Before doubling this down the road, I would consider Flourish Trace as well; I found that using both as opposed to doubling the Comprehensive provided more benefit to the plants but kept algae reduced. The addition of Trace with Comprehensive was very noticeable with my floating plants and my chain swords.
Byron.