U tube question...

[fish.freak]

My hob overflow cant keep up with my my return, so I have it dialed down with a ball valve at a 45 degree angle. My question is if I add another u tube can I increase the flow, and will that make it more prone to flood?
Thanks, Scottie.

[tdwyatt]

Originally Posted by fish.freak

My hob overflow cant keep up with my my return, so I have it dialed down with a ball valve at a 45 degree angle. My question is if I add another u tube can I increase the flow, and will that make it more prone to flood?
Thanks, Scottie.

no.

Make sure the overflow you use has both ends of the U-tube submersed in water in chambers inside the compartments (so that even if the water pumps fail, the overflows will still have ater around the base of both sides of the U-tube). This will maintain the siphon and prevent issues associated with siphon failure. Adjusting/positioning the intakes correctly will prevent air bubbles from being sucked into the overflow U-tube to prevent an airbreak from forming that would stop your siphon as well. Make sure that the angle cut in the base of the U-tube is positioined away from the divider in the overflow chamber so bubbles rise to the surface rather than get sucked into the siphon.


HTH

[Doug1]

Scott which overflow do you have?
Since the ? revolves around U tube , i am guessing its an in/out , box fed by single u tube, if that the case the max flow rate will probably be dependent on the depth of the external box and the size of the drain bulkhead, rule of thumb, drain bulkhead ID should be matched to the U tube, granted U tubes are a little more trouble to dial in and maintain than an drilled tank but not an insurmountable obstacle

[fish.freak]

Its a Truvu hob (black in tank overflobox w/ clear hob counterpart). I think the utube and bulkhead are 1". It had been running fine since I got the new pump dialed in for a few months w/ no air bubbles , I just wanted to see if there was a way to increase the flow a bit.

[Doug1]

Originally Posted by fish.freak

Its a Truvu hob (black in tank overflobox w/ clear hob counterpart). I think the utube and bulkhead are 1". It had been running fine since I got the new pump dialed in for a few months w/ no air bubbles , I just wanted to see if there was a way to increase the flow a bit.

It should be balanced but you might try addig a 1/2 U tube and see if that increases the flow,
Caution try this only when you can observe and correct if need be

[fish.freak]

I'll experiment after I get back from NYC

[Doug1]

OOOPS that was supposed to read 1/2" tube, the size of the drain seems to be the limiting factor, as well as depth to get more of a push

[partobe]

Welcome to NYC fish.freak!! Hope your having fun. "sorry for this interruption now back to your normally scheduled thread"

[Doug1]

Originally Posted by partobe

Welcome to NYC fish.freak!! Hope your having fun. "sorry for this interruption now back to your normally scheduled thread"

Hehehehe no one thread jacks here

[nobody]

the u tube has nothing to do with the flow its the diameter of the bulkhead in the skimmer box. adding another u tube will just give you a salty swimming pool in that room. oh and buy a smaller pump restricting the flow will shorten the live of the pump especially if its a mag drive. I talk to the reps. about this alot and its a big deal with them.

[Geoff]

restricting the flow out of a pump does not shorten the life of a pump. restricting the output is no different than having more head pressure on the pump. in fact increasing head pressure can lower the wattage used by the pump, thus adding less heat to the system. this only works for A/C motors though.

the bulkhead leaving the overflow box is your bottleneck. if it is a 1" drain than you are only going to get about 660gph max out of that overflow. if you have a mag 12 as a return then you are going to need to valve it down quite a bit to get the flow down that much. if you do have a Mag 12 or so then going to a smaller mag, like a 7 would make more sense in the long run. only because of total watts being used.

G~

[nobody]

i have to respectfully disagree. i talk to supreme reps all the time at work who tell us a large majority of their defective returns are based on pumps that were restricted. I didnt believe it either but they set up two mag 12 in the back roomand after 3 months the restricted pump had less output at full flow then the unrestricted pump.

[Geoff]

then they need to redesign the pumps, this should not be occurring.

it is always a good idea to get the pump that most closely matches the flow of the overflow after return head height has been calculated. having to big of a pump just wastes more power than necessary.

the Mag 12 was just an example. in most cases a Mag 7 is a perfect fit for a 1" overflow with about 5' of head.

G~

[nobody]

yes that is true supreme clearenced all mag drive pumps and are being redesigned. never tried other pumps but just assumed it makes sense.

[fish.freak]

Originally Posted by Geoff

restricting the flow out of a pump does not shorten the life of a pump. restricting the output is no different than having more head pressure on the pump. in fact increasing head pressure can lower the wattage used by the pump, thus adding less heat to the system. this only works for A/C motors though.

the bulkhead leaving the overflow box is your bottleneck. if it is a 1" drain than you are only going to get about 660gph max out of that overflow. if you have a mag 12 as a return then you are going to need to valve it down quite a bit to get the flow down that much. if you do have a Mag 12 or so then going to a smaller mag, like a 7 would make more sense in the long run. only because of total watts being used.

G~

its a Eheime 1262 w/ only 600 gph at 5' and if it ran full blast it would flood.