It can take up to a year or better for the rams to fully mature, meaning that they will not be successful raising their own young and eggs until that point, if ever. Your gH is a tad bit on the high side, which may be part of the reason why they are eating the eggs, you probably have a low fertilization rate. I will agree with Dave on the water temp thing, discus and rams are very similar with their needs as far as water temp and water quality goes. Even more so when they have eggs. I would not reccomend using peat or leaves to lower the pH, as pH has very little to do with fertilization, its water hardness. Both of those will do nothing to soften the water. RO water is the only sure bet to soften your water, purified drinking water that you can buy at a store will work as well. That total dissolved solids in RO water is extremely low, doing a 50-50 mix of RO and tap water will lower your water hardness to a level that will allow for better fertilization rates with the eggs. Hard water causes the "shells" of the eggs to harden and not allow the sperm to penetrate them, thus not allowing fertilization. As a general rule of thumb pH and water hardness go hand in hand, but its not always the case, as I mentioned adding peat and such only impacts the pH of the water, not the hardness. Lowering the pH can be used to trigger fish to spawn, but since your rams are already spawning there is no need for that. So I would reccomend doing 50% tap water and 50% RO water with your water changes from now on, which I would also step up to doing 2-3 50-60% changes per week to keep the water quality up, this will help quell fungal infections on the eggs. You can't get water too clean for raising eggs. Avoid doing much around the area where they have laid eggs as well, since this will stress the parents out and may cause them to eat the eggs as a survival technique. The eggs then become a threat to them, since they may be drawing predators, so eliminating the eggs will also allow them freedom and stop drawing the predators. Just give them time and warm clean water, I'd suggest around 85-88 for water temp.
