Pepe, eat 2-5 stalks of celery a day and keep drinking that water. I usually just eat two stalks and that's enough for me. You can juice it if you hate chewing it, it really takes a long time. I have heard people say L-Arginine helped with loads but personally I haven't noticed any improvements with it other than EQ and vascularity, but I've only taken it for a few weeks.
If you want supplements, try 3-6g of Peruvian Maca every day; 10mg of Bioperine, but no more than 20mg; you could also try Lecithin, especially if it becomes too watery.
There are a lot of others things you can do for load size, but I think anything more would be pretty expensive. One thing to keep in mind is that even though there are some nice semen enhancing mixtures out there, they don't always work for everyone since our bodies work differently. We all have different lifestyles and diets right? Try experimenting with these. If that doesn't work out, maybe you can try some other supplements.