Not an expert but, I think 40ml of Flourish (trace or comprehensive ?) per week it's not enough for an 180g tank. I dose 45ml/week in a 55g tank + extra Iron. This are my micros and macros solutions:
500 ml bottle:
I added 7 ml undiluted Metricide 14 (or 10-11ml Excel) to the DI water and let it settle for 10 min or so then I warmed up the water a bit.
I mixed 3 tsp CSM with 5 tsp Miller + 1.5 tsp 10 or 11% DTPA + 1.5 tsp Fe Gluconate + 1 tsp MnSo4
Dosing 15ml 3 times/week for a total of 45ml/week for a 55g tank.
KNO3 solution: 100g in 500ml bottle dose 15ml 3 times/week (30 to 40ppm/week)
KH2PO4 solution: 30g in 500ml bottle dose 10ml 3 times/week (5 to 7 ppm/week)
K2SO4 I dose dry 1/2 tsp 3 times/week (20 to 30 ppm/week)
CaCl2 solution: 100gr in 500ml bottle dose 30ml 3times/week (30ppm/week)
MGSO4: 100gr in 500 ml bottle dose 25ml 3 times/week (7 ppm/week)
Metricide 14 5ml daily
Ultimate Gh booster 2tsp with WC only
1 tsp Baking Soda to raise Kh from 3 to 4, WC only
All this dosing is for a 55g tank.
Please keep in mind that I dose Ca and Mg b/c I have very soft tap water.
"Ich Hatte Einen Kameraden"
"In the Shadow of Hermes"