hi, firstly great site, myself and my dad have kept koi for a few years now,ive just bought a house of my own and am planning to build my own pond,size 12ft by 8ft by 5ft depth,after visitng coldwater collection i noticed ken ,instead of having a domed bottom drain,he had a flat grid fitted flush to floor,i was planning to run a 110mm pipe to middle of pond with a 90deg swept bend and fitting a flush floor grid over the top instead of a adjustable dome like standard drains,will this cause any problems such as pressure to my vortex, pond will be 3000gallons and fitting a 2600gph pump with adjustable regulating valve,just wondering if this will work because i wont have dome (mushroom) over my drain. be gratfull for your advice many thanks