I think I went overkill on my main tank and wasted a bunch of money
I actually have 2 1-1/2" ball valves off there (one right off the overflow, and one going into the sunp -really should have used a union on there) thats ~$60 worth of valves :O
I am now plumbing in my frag tank and I will for sure use a ball valve on the return to throttle flow if required.
I am just hoping I am not making a mistake if I don't throw one on.. but then again I can always splice into the flex pvc line and throw one on down the road if I think it is required.. maybe just a union on there eh?