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Thread: Venturi Jets or Blower for spa?

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    Venturi Jets or Blower for spa?

    I'm building a fairly large oasis pool with a 12' outside diameter and 9' inside spa (18" sitting ledge). 3' spillover to pool. Seperate 2HP jet pump for spa. 400,000BTU heater. PB planning on doing venturi jets, but a PB I ended up not using was saying I would appreciate a blower. PB said blower not really necessary...can be loud...something else to maintain. PB has venturi jets in contract. Thoughts?

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    Join Date
    May 2011
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    Orange, TX
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    Re: Venturi Jets or Blower for spa?

    There are pros and cons to both. With the venturi knobs you get spa controls for air without taking up an extra relay in your control box. With a blower you will have to use one of the relays in the control box and turn it on or off with your remote. (assuming your putting in a decent control system). For my system I have 7 jets. Each jet takes a venturi knob. I did not want the look of seven different knobs on top of the spa coping. I thought that might look tacky. I think this looks okay if it is only 4 or 5 knobs for 4 or 5 jets. Thus, I went with the air blower for that sole reason, and the blower option was slightly less expensive. They make some very quiet blowers, thus I wouldn't worry to much about noise. I guess at the end of the day it is personal preference. However, it is correct that the blower is one additional piece of mechanical equipment to run electrical to and maintain. Just my 2 cents. I can't comment on performance on one vs the other as mine is still in the construction phase. I will say I have sat in one with venturi's and I thought the air pressure felt just fine.
    20,500 gallon free form, 6X9 hot tub w/ spillover, 18" jumping platform w/ 3ft shear descent on chopped rock, Travertine coping, 2.5HP Hayward 2-speed filter pump, 525 Hayward Cartridge filter, 350K BTU Hayward NG Heater, 2HP Hayward water feature pump, Satin Matrix Northshore Carribbean, Jandy PDS-8 Controls

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    mas985's Avatar
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    Re: Venturi Jets or Blower for spa?

    I was under the impression that all IG spa jets have a venturi of some sort. It would be short of impossible to mix air with pressurized water otherwise.

    In most cases, a blower is used when the air line is too long for just a natural venturi so the air intake is insufficient for the jet. Also, the force of the jet is caused by the water pressure and not by the blower or air. A blower simply makes more bubbles.

    WARNING: Don't let the PB use less than 2.5" pipe for the spa or you might end up with weak jets. With a 2 HP I would even go with 3" pipe.
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

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    Re: Venturi Jets or Blower for spa?

    Mark, you are correct. They all have venturi's, which are plumbed into the main plumbing of the spa. I think the difference in options are a blower that forces air to the venturi under positive pressure, or a small suction port that includes an adjustable knob that is normally installed on top of the coping. In this option water running across the venturi creates a vacuum, thus pulling air in. You adjust the knob to increase or decrease the amount of air going to the jet. I guess in option one you get that same vacuum effect, but it is pulling the air from the blower rather than the small suction knobs/ports. One advantage to the suction knobs is you can actually adjust the amount of air going to the jet, wheras with the blower I think it is either fully on or off with no adjustment.
    20,500 gallon free form, 6X9 hot tub w/ spillover, 18" jumping platform w/ 3ft shear descent on chopped rock, Travertine coping, 2.5HP Hayward 2-speed filter pump, 525 Hayward Cartridge filter, 350K BTU Hayward NG Heater, 2HP Hayward water feature pump, Satin Matrix Northshore Carribbean, Jandy PDS-8 Controls

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    Re: Venturi Jets or Blower for spa?

    Thanks for info guys. The plumbing conduit IN the spa is 2", but it is fed with a 2-1/2".

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    mas985's Avatar
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    Re: Venturi Jets or Blower for spa?

    You should be able to design the spa the same way with or without a blower. The difference is the length of the air line. If you want to bring the air intake line back to the pad, then a blower will probably be necessary. If you don't mind having the air intake line close to the spa, then a blower is probably not necessary.
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

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    guamguy's Avatar
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    Re: Venturi Jets or Blower for spa?

    This may be unusual, but our spa has a venturi that aerates the water coming through the jets, and a blower that feeds air through small ports in the spa floor.
    12,800 gallon IG plaster kidney-shaped pool, waterslide, 800 gallon spa.
    1HP 2 speed Sta-Rite pool pump, 1.5 HP Sta-Rite spa jet pump. 2 skimmers, 1 main drain
    Purex-Triton TR-60 325 lb.sand filter. 2" Plumbing, Intex SWCG, TF-100 test kit.
    Link to pics of my pool! http://www.troublefreepool.com/my-oasis-t26558.html

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    Re: Venturi Jets or Blower for spa?

    The PB set mine up with venturi to the jets and a blower that sent air to holes just under the seat. The spa jet performance was miserable with just the venturi. I have a 3HP pump and was expecting so much more.

    After months of going back and forth with the PB, he finally agreed to run the blower to the venturi feed. The jets are now more powerful. I would recommend the blower unless you are fine with having weak jets.
    Phoenix, AZ
    Unknown pool size -Diving pool

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    mas985's Avatar
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    Re: Venturi Jets or Blower for spa?

    JeffJeff, How far is it from the spa to the air vent? How many jets do you have and how large is the plumbing?

    I have a 1 HP pump with 6 jets and no blower and both the force of the jets and the air bubbles are quite extreme. It all depends on how your PB designed the plumbing. With large water and air pipes, you should be able to get away without a blower and using a small pump.
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

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    Re: Venturi Jets or Blower for spa?

    Quote Originally Posted by mas985 View Post
    JeffJeff, How far is it from the spa to the air vent? How many jets do you have and how large is the plumbing?

    I have a 1 HP pump with 6 jets and no blower and both the force of the jets and the air bubbles are quite extreme. It all depends on how your PB designed the plumbing. With large water and air pipes, you should be able to get away without a blower and using a small pump.
    what did your PB use on your spa? 2 inch?

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