mag 12 return on a 75g too much?

[Aj Flip]

after head loss its around 800gph with 3 exits into the tank

should i turn it down a bit and get more powerheads?

[Purple Haze]

Depends on how big your drain(s) are.

[Aj Flip]

drain is 1.5"
i use 2 1" u-tubes on the overflow box

[shag26272]

sounds like a flood waiting to happen, I would go with a smaller pump. ive never used an overflow box before but I would think you wouldnt want to try to push it to its limits.

[Aj Flip]

so ill just reduce flow with the ball valve?

[Purple Haze]

No. Either redirect the excess flow back into the sump via a tee or move to a smaller pump. Reducing the flow with a ball valve will shorten pump life.

[shag26272]

I doubt it will shorten the pump life, it will actually use less electricity.

[Aj Flip]

just curious, why is it bad to have too much flow through the sump

[Ness]

Loop in a chiller or maybe even a barrel for water changes. You could even T in your carbon/phosphate reactors, or an external skimmer to use up some of the excess gph.

[flyyyguy]

<a href=showthread.php?s=&postid=13221611#post13221611 target=_blank>Originally posted</a> by Purple Haze
No. Either redirect the excess flow back into the sump via a tee or move to a smaller pump. Reducing the flow with a ball valve will shorten pump life.

false

it is no different than running more pipe or a higher lift creating more head.

depending on the pump, it will use less electricity and be less wear and tear on the pump to scale it back with a ball valve


use a ball valve on the output side. as long as you arent dead heading it, it will be fine and what you should do

besides...there is no point in moving any mroe water through your sump than you skimmer can process. water is surface skimmed out of the tank to be skimmed....this surface skimmed water is the dirties water in the tank.....dont intentionally set up yoru system to just recirculate it it without being skimmed....

skimming 100% of this waer is unrealistic without a immense amount of effort, but roughly match flows and you are at least making the effort

as said, T'ing off the return to power a small chiller or cansiter filter for gfo or carbon is a good idea as well if you use either. it can eliminate a pump or two

[crvz]

agreed with Fly Guy, and have experienced the same thing by measuring electrical load on pumps. if you think about it, magnet driven pumps have free spinning impellers... the more you slow it down the less wear you'll have on the moving parts. the housing has no moving parts, so increasing the "load" due to head doesnt matter at all.