Good but cheap nutes?

[FalseFlash]

My tomatoes are feeding too much for me to keep up, they are sucking up close to 40 gallons per day. The 55 gallon tank would be full in the morning, then the next morning it would be almost empty!

The tomatoes I'm growing are giant belgium, they are pretty big but yet still green. They are taking forever to ripen, biggest tomato's I've seen yet. This is most likely the cause. I only have 14 of them growing in the system, nothing else. They are pretty tall, maybe about 5-6ft.

To be honest I kinda want them to just be done with already, it's becoming a lot of work and starting to be costly. Buying nutes in the gallons is just not enough anymore. So, do you have any suggestions and cheaper alts to flora series?