To Drill or just Over-flow?

Well, I try to keep my DT/Sump turnover rate around 7x give or take. Some say 4-5x. Some say 10x. I just split the difference. If you were to have 1500GPH capacity of outgoing water, it is going to be regulated by the return pump anyway. The internal overflow and external overflow have the same basic design so if you have a return pump that only does 500GPH at 5', that is what your turnover is going to be based on. The 1500GPH capacity will easily keep up with it. However, if you were to design an overflow with 700GPH capacity and ran a return of 800GPH, then the DT is going to fill up and the sump is going to drain, because your outgoing is going to be over taxed. This was a difficult concept for me at first, but if you look at the how the entire process works, it begins to make sense. The way the water gets to the holes to drain is key. The water is really pushed past the 'overflow guard' (I cannot remember the name of it---so there you go) and it just drains down via gravity. Gravity down, pump up. As long as the pump doesn't outdo the gravity feed, you are cool.

 

you have a PM

 

No not at all. The overflow is only going to drain what your return pump puts in the tank. No more, no less. An overflow that is rated at 700 gph will do 1-700 gph and the one that is rated at 1500 gph will do 1-1500 gph. with the 1500 you would be safer.

 

Ok, so I have a Mag 9.5 that I wanted to use about 900gph. So even tough the overflow is up to 1500 it will only push between 800-900 gph?

 

with head loss, plumbing, and fittings you are going to lose a substantial portion of flow so you wont get 900 gph unless your sump and tank are at the same height. I would guess that youll end up somewhere with 600 to 700gph after it has all been set-up.

 

I feel it is always better to over size on the return pump for the following reasons.
1)To compensate for fittings and head pressure.
2) more circulation is almost always better as long as your overflow can handle it.
3)You can add t-offs and valves to the OUTLET side to regulate flow and incorporate future upgrades or options without having to purchase more pumps when implementing those items.

For bottom drill applications the "Durso Standpipe" rocks and is super cheap and effective for a DIY project to reduce noise and bubble production in spillways.

 

sorry to jack this thread but what would you recommend for a bottom tempered tank as far as where to drill the hole, bottom, middle? im looking to drill my 56 column sometime in the future.

 

Without question.....DRILL, DRILL, DRILL!!

 

are you kidding.. no way.. Tempered glass does not drill.. dont try it..