I had a tank that was using flourish. After working through a long list of macro deficiencies it started to do well and then started a slow crash . I couldn't get any plants to grow algae took over the tank. All macros were present in sufficient quantities. The problem was that I was using RO water. Flourish is definitely designed for use with tap water only. But even then it may not work. I have concluded that flourish doesn't have enough micro nutrients to do anything in very soft water.
Using Rotalbutterfly.com the results of my flourish dose was (in ppm):
NO3 0.06753
P2O5 0.00219
P 0.00096
PO4 0.00285
K2O 0.08113
K 0.06731
Ca 0.0307
Mg 0.02412
S 0.0608
B 0.00197
Cl 0.25215
Co 0.00009
Cu 0.00002
Fe 0.07016
Mn 0.00259
Mo 0.0002
Na 0.0285
Zn 0.00015
I also tried switching to CSM+B micro fertilizer. This is a popular choice for high tech aquariums. it didn't work. I eventually learned on of its key ingredients EDTA (a chelating agent) breaks down at a PH 6.5 or higher. My low tech aquarium is at a PH of 7. For an aquarium with a PH of 8 use Fe EDDHA it is the most stable at high PH.
This month I decided to do what some other people are doing and make my own micro fertilizer
http://www.plantedtank.net/forums/1...rameters/1221018-custom-micro-mix-thread.html
For my micros i am currently dosing:
Fe DTPA at at 0.02ppm (Sodium borate) (will switch to boric acid soon
Mn at 0.05ppm (manganese sulfate)
Zn at 0.02ppm (Zinc sulfate)
Cu at 0.006ppm (Cooper sulfate)
Mo at 0.001ppm (sodium Molybdate)
Ni at 0.001ppm (Nickel sulfate)
These levels are based on the information at this site:
http://soils.wisc.edu/facstaff/barak/soilscience326/macronut.htm
You can see that the levels I am using now are massively higher than what Flourish provided.
For macros i am dosing KNO3 to 10ppm NO3 and KN2PO4 at 1ppm PO4. For Ca, Mg, S and Cl I am using a GH booster I made that has CaSO4, MGSO4, CaCL2. I tend to keep my GH at about 2degrees.
How is it working? Very good I have growth on multiple plants (one pearling.) I still have a lot of algae but it appears to be falling back a little. A long way to go but it is an improvement.
Hopefully dosing flourish 2 times a week works but I have my doubts it will.
I am not saying you have to make your own fertilizer but whatever path you follow will be full of challenges. If you use my recipe with your hard water you could wind up with toxic levels copper or other nutrients. You could try other premade fertilizers but most are missing Calcium, sulfur, and chlorine which are all critical for plants. Furthermore using Rotalbatterfly.com I haven't found a fertilizer that comes close to what I am using now. The levels in most micro fertilizers are all over the place (the nutrient is either missing, at a very low dose, or a little higher than flourish).
As to lighting i have a dimmer on my light and I did a sweep from very low lighting (1%) to very high (100%) I didn't find any setting that would work. Note the light is built with the capability to to run at EI high lighting levels if I should ever decide to use CO2. It is currently running at 50%
When you have hard water you often have very high levels of calcium with a small amount of magnesium (about 90% Ca and the remainder Mg and other elements). For some people with high tech tanks this results in magnesium deficiency even though magnesium is present in most fertilizers. I am not saying you have magnesium deficiency but it is possible for it to happen with hard water.
