I would like to try using the EI method now my tank is planted up. The problem is this. I use rainwater in my tanks, and have done for several years, having almost no problems with fish compared with those when I used tapwater. The Discus especially benefit as we have very hard water in our area. My problem is this. With a 250l tank, a 50% water change is not surprisingly 125l and especially in winter, there's no way I can change this much water in one go, as it needs to be stored in the house to warm up. (I don't fancy putting water close to freezing in a planted discus tank!) Can the EI method be used if following a method such as 50 litres being changed twice a week? (or even better, 25 litres every two days, though I suspect this is not enough) If I carry out water smaller water changes every couple of days, how could the dosing regime work? Is it at all possible? Any info gratefully recieved!!