In ground hot tub has 3 floor drains with safety covers, but only 1 actually pulls suction

[mtc89]

I have wondered about this for a long time, because I only ever see leaves and debris stuck against one of the three covers. All three drains have Paramount SDX safety covers, and I wanted to see if there was a ton of junk underneath the covers, so I drained the tub and removed all 3 covers.

The one suctioning cover had tons of bark, seeds etc clogged in the underside of the grille, but the other two were pristine. I even blocked the suctioning drain with a small rubber ball, and the other two did not start suctioning at all, it just jammed up the pump. I changed the pump valves to try suctioning from the pool + tub together, and still those two drains did nothing.

Does anyone know why my hot tub would have two redundant drains?

 

[Rocket J Squirrel]

To make it look like the spa passed the safety code when it does not?

 

[RDspaguy]

Depends on the tub. Is it fiberglass or concrete? Does it have a skimmer with a basket or filter? How many pumps is it running?
My first guess would be it's a fiberglass shell set up for a second pump option that was not used.

 

[birdman579]

My spa also has 3 drains: 1 for the filter pump & a double drain for the jets pump. I don’t understand how the single drain is ok from an entrapment standpoint, but that’s what I have. I have considered switching to a single pump for both filtering and jets to reduce complexity. In this case, I would tie the drains together. I wonder if someone did the same thing on your spa except only used the spa drain and abandoned the double drain that has previously been used for the jets pump. How many pipes come to the equipment pad? Or, have you confirmed they are not clogged? I had a pool company forget to remove a winterizing plug on one of my drains causing an issue.