Its from the main pump in a wet-dry system to the bottom bulkhead on the bottom of the tank. The two long sweep 90's would fit better but the if I need the flow would two 45's make much of a difference.
I will probably have enough current but I havent set up a tank this size. Its a 240 long with 2 mag 18's and 2 xp3's. I didnt know if there was a big difference between the LS 90's and 45's....
Two 90's will give you 180 degrees but two 45's will give you only 90 degrees
The sweep 90's will be less (all things equal). However, the restriction from fittings is significantly less than what is commonly believed. Between a single sweep 90 and an elbow 90 on the system, you wouldn't know the difference.
When you say it is from the pump I assume you are talking about a pressurized return line. What kind of pipe are you using? I have never come across long-sweep 90's in pressure-rated PVC, only grey electrical conduit, ABS, or DWV PVC. DWV fittings have a shorter socket and technically are not meant for pressure systems. That said, they will work fine, especially in a low-pressure situation (you won't be generating 100 pounds of pressure like you could get in a water service).
Back to the original question. Like everyone has said, the difference would be negligible. You would get slightly less turbulence from a long-sweep than two 45's, but neither will cause restriction - PVC fittings are all "full-flow", in fact the fittings have a slightly larger working diameter than the pipe itself.
It is coming off a mag 18 to the return bulkhead on the tank. The mag says there flow rates are through I think like 1.5" pipe or something crazy like that....the output nozzle is only 3/4".
The return bulkhead on the tank is a 1" threaded so from the pump to the bulkhead I was going to try to increase the 3/4" output of the pump to whatever size would fit on the OUTSIDE of the bulkhead thread (not the 1" on the inside)...where the nut goes...follow? Then it would drop to 1" through the bulkhead and onto however I make the return in the tank.
So I dont think im going to use the 45's....so yall are saying that 2 reg 90's wouldn't be much different than the LS 90's? The reg 90's would fit even better lol...
I am using 2 mag 18's and im looking for at least 1000gph from each after the plumbing. I was thinking about making a manifold loop for the return in the tank....a rectangle with 1" pipe in a complete loop around 1/2 of the top of the tank...with 4 locklines nozzles coming off the manifold loop....follow? There would end up being 2 seperate manifolds one for each pump and each manifold covering 1/2 the tank.
Let me put it this way. The restriction of a regular 3/4" 90 is equivalent to eight one hundreths of an inch of vertical head. It will take 100 fittings to equal the restriction of raising the return pipe eight inches. The restriction of the same fitting in 1.5" is about ten times less, or eight one thousanths of an inch of head (it will take about 1000 fittings for the same example). In other words, it doesn't make a real difference what you do.
It is coming off a mag 18 to the return bulkhead on the tank. The mag says there flow rates are through I think like 1.5" pipe or something crazy like that....there output is only 3/4". The bulkhead is a 1" threaded so from the pump to the bulkhead I was going to try to increase the 3/4" output of the pump to whatever size would fit on the OUTSIDE of the bulkhead thread (not the 1" on the inside)...where the nut goes...follow? Then it would drop to 1" through the bulkhead and onto however I make the return in the tank.
So I dont think im going to use the 45's....so yall are saying that 2 reg 90's wouldnt be much different than the LS 90's? Cuz the reg 90's would fit even better lol...
I'm not sure that adapting to the outside threads is a good idea.
The inside threads are what are called a "tapered thread" - the diameter of the opening decreases slightly as you go in. A male tapered thread fitting gets slightly larger in diameter. This causes the threads to fit tighter and tighter as you tighten the joint.
The outside threads on your bulkhead aren't tapered, they designed just like a bolt. You might be able to make it work with plenty of teflon tape, but it isn't the "correct" way to do things.
I would definitely use the regular 90's. Like I said earlier, long-turn or long-sweep 90's are meant for drains, not pressure systems.
Let me put it this way. The restriction of a regular 3/4" 90 is equivalent to eight one hundreths of an inch of vertical head. It will take 100 fittings to equal the restriction of raising the return pipe eight inches. The restriction of the same fitting in 1.5" is about ten times less, or eight one thousanths of an inch of head (it will take about 1000 fittings for the same example). In other words, it doesn't make a real difference what you do.
