Help My Yeild

I'm very disapointed in my hydroponic system,
First of all let me tell you about my system.
my system Is a 55 ga aquarium with 5 10in planters that sit in the top of it.
I use clay pellets as my medium and I have a 66gph water pump that splits off to the 5 planters and is gravity feed back down, I also use airstone as well.
I started them under a 250 watt mh for the veg. and I upgraded to 1000watt hps during the flowering.
Their about 3 feet tall now and have been budding for 8 weeks.
I was feeding them for 1hr every 3hrs for the first 7 weeks useing Dutch Master Gold Flower A/B, Max Flower, Silica, Zone and also Superthrive at an E.C. of about 2.2 - 2.5 or 1500-1750 ppm and a ph of 6.0 .
The Problem is over the last 8 weeks I have only been able to havest about a half oz of dried bud off each plant.
I was told to use a bud boster called Gravity and I've been useing it for the last week and feeding them constantly.
Since then the buds have alot more resin on them but they haven't gotten any bigger.
What can I do?

how long did you veg for

That sucks dude...whenever I have gotten lower yield it has had to do with node sites and light. I've never experienced nutes impacting yield directly. Good nutes make a bigger plant. A bigger plant gives you higher yield. Do you have pics of the girls before you chopped them? Another thing that has helped create more nodes is re-budding girls. Leave a dozen or so little buds near the bottom of the plant, re-veg for four/five weeks, then re-flower again. Four or five big shoots will grow from each old bud site. Makes a real nice bushy girl.

What strain is it?
Are you sure about those ec levels?
Some strains dont yield very much unless you veg them for a long time and top/fimm them

well I veg'ed for 4 months before I started budding and origanally I was going to banzi the plants but 3 months in I was able to move them to a bigger grow room so I let them grow taller
til they were about 3 feet.
so far I have only havested the tops of 2 out of the 6 I have and I left those 2 alive and then one of them has turned purple.
so if I have the lower half of the plant still alive will it bud more on its own or do I have to reveg and if so can I reveg under HPS?

Yeah you can reveg.
What strain is it?
4 months of veg and only 3 feet tall?
Reduce your ec levels during flowering imo