Limno Transparent Leaves, Nutrient Deficiency

Limno leaves becoming transparent. Anyone here have corrected this issue before? I have a 55g tank. My kH is at 4dkh, I dose 1/4 tsp KNO3, 1/8 KH2PO4, 1/8 K2SO4, 1/8 CSM-B. EI method. CO2 around 35ppm range. I drop my pH from 7.2 to 6.5-6.6. Photoperiod around 6hrs

 

I don't have a reliable GH test kit, its a liquid test kit and I cant interpret the reading. And no I don't know what the Ca and Mg levels are, I don't have a test kit for those. I probably don't have any Ca in there, just the 4 ferts I posted is what im dosing in the tank.

Should I buy some Calcium Nitrate Ca(NO3)2 to replace the KNO3 since im already getting the Potassium from the other 2 macros?

 

My apologies, I rechecked my information. My true degassed pH is 7.69, which is dropped to 6.5-6.6. Also the KNO3 is 1/2 not 1/4. Substrate is 50% ecocomplete and 50% ada Amazonia 2. Lighting is 7x 60w CFL pigtail bulbs 6500k. Not much fish. 12-15 rummynose tetras. Tank is about 4-5months old.

PS, I do remember growing limno before and I never ran into this problem. The only thing I can think of is because my tank consists of 50% RO and 50% tap, vs before where it is 100% tap. I think it could be a Ca+Mg issue. Only reason why I have 50% RO is to make my rummynoses a bit happier as they like more acidic water, and to lower my Kh a tad for my plants. My tap is at a 8dKh I drop it to 4dKH.