Planted Tank Guru
Join Date: Jun 2004
Location: Baton Rouge, LA
There are usually two issues when using a terrestrial fertilizer in an aquatic environment.
First is the source of nitrogen. Terrestrial fertilizers typically use "ammoniacal" nitrogen sources - meaning ammonia producing. These are safe and effective on land, and being cheap to produce, we can assume this is what it contains. But ammonia, being fish waste, is of course harmful to fish. Aquatic fertilizers primarily use more expensive nitrate based nitrogen sources, which being the same as the end product of the ammonia -> nitrite -> nitrate biological filtration process, are much better tolerated.
Second is the copper content. Copper in excessive quantities is also toxic in an aquatic environment. Compare the ratios of your fertilizer:
To CSM+B, a commonly used concentrated micronutrient source, that contains no N/P/K and so is used in much smaller quantity:
Adjusting the dosages to provide the same amount of iron (a good reference point for comparison), the CSM+B provides about 35 times less copper! Even if you had not provided a chemical breakdown, the turquoise color - characteristic of copper sulfate - is still a giveaway to high copper content.
Such a fertilizer can only be safely used in reduced quantity. Further reduced if fish are present, and further still with sensitive fauna like shrimp. Given that you have fish, and a high nutrient demand due to your light and CO2, I don't think this will be of much use to you.
You're already getting too much nitrogen (as nitrates) from fish food, which will need to be reduced with water changes. I'd try to reduce them by half to 50ppm. Once this is achieved, given the typical composition of fish food, that will probably put your phosphates at about 10ppm, which is also acceptable.
What fish food lacks is potassium (K), plus iron and the other trace micronutrients. If you can find a source of pure potassium sulfate, plus a micronutrient mix with high iron and low copper (like CSM+B), you'd be set.