Ballast Tank Set Up

Hi guys,

Im looking to add more ballast to my boat and Im brainstorming the smartest way to go about it. I have an MC 08 X1, which has two hard tanks built in into the back.. I would like to add another two bags around 300-400 pounds. Ive been looking at the V-Drive Fly High Pro X sacs (400 lbs a piece)

Im looking for some input to incorporate these new bags with the existing system. This is the best design I can think of so far but let me know if you see any potential problems.

Its basically hooking the two tanks (old hard tank and new bag) up in parallel. See the attached flow diagram should make it a bit clearer

Then I would fill them individually, isolate one tank by closing either valve 1 and 3 or 2 and 4, wait until it overflows, then switch the position of all valves and fill the other one. I don’t see how this would add any extra stain on the pump which is my biggest concern. I want to try to not have to add another pump to save money but don’t want to burn out the existing pump.
From what I can find about these bags, theres a fill hole and vent on the top and a drain on the bottom, if any could confirm the layout of the holes on the bag that would be very useful so I can figure out how to attach them exactly. Are you able to buy the various connectors at home depot or someplace like that? Ill also need 8 shut off valves and about 10 feet of hose and some c clamps.

Ill attach the other design I had which was setting them up in series but I think it would add an extra strain on the pump since it would then have to pump and hold the weight of two tanks. Plus there would be complications with emptying the sac which is why there's those extra valves. Overall it seemed much more complicated then the other design, the only benefit is you wouldnt have to change over all the valves during filling, only between emptying and filling.

Let me know what you guys think, and insight would be very useful

Also has anyone used wakecord.com to buy these bags, I couldnt find any local or used bags (Im in Canada not as much stuff up here). The ones I was looking at are 200 bucks a piece so 800lbs in total, seemed fair to me.