Identify purpose of these pool components

[JamesW]

The VGBA Code requires two main drains tied together for safety.

There should never be only one main drain for any suction.

However, the pool might have been built before the rule.

Does the spa have a skimmer?

Are there 3 main drains in the spa or only two.

 

[JamesW]

Some Spas use a separate jet pump for the therapy jets to give strong jet action.

 

[JamesW]

If the PVC line is for fill do you think it would be routed to the location where all the equipment is? There is one PVC water line connected to a hose not too far from the right pump but that is a simple on/off.. I'm guessing for a handy water source when cleaning.

Does water come out of the line when you open the valve?

If it is a fill line, there should be a valve somewhere.

 

[spaHabit]

No skimmer for the spa. Only two I believe. In addition to the two spa drains shown, there is only a return port which is less visible in the photo I posted.

 

[spaHabit]

BTW, I I just clicked your link and became a supporter. I have to say I and extremely impressed with not only your help but also all the wonderful information on the site. It has really helped make me more confident with pool ownership. Truth be told, I really didn't want a pool ... my wife and I are both, Hmm, older, and never had a pool previously... we probably won't get much use from it... but she loved the house and so we ended up buying. I'm so glad I found this site after my first two visits to the local pool store... I was not impressed with the knowledge there. After buying the TF-Pro Salt test kit and following advice here I was able to quickly balance the pool chemistry on my own. More importantly, I now understand the why of the various additives.

 

[JamesW]

Is this a suction or return?

 

[spaHabit]

That's the pressure line from the middle pump (return from pump confirmed). When the pump starts, a lot of bubbles come from it.

 

[spaHabit]

Off topic here but perhaps a quick question, can you identify a post that shows an equation for how Calcium Saturation Index (CSI) is calculated? I've done quite a bit of searching this site and google but haven't found one yet ... closest I came to so far is chem_geek's pool-water-chemistry. But atlas no joy there. I'd like to add a CSI calculation to the spreadsheet I created to track my pool test results... easier for me than using an app.

 

[JamesW]

view-source:https://www.troublefreepool.com/calc.html

 

[JamesW]

 

[JamesW]

 

[spaHabit]

Good stuff Thank you.

I know it's not strictly necessary but it's nice to include in the spreadsheet while I'm at it. We have hard water here in San Diego so its nice to have some sort of indication other than CH which tends to run high when water is added.

 

[spaHabit]

Maybe a fill line.

Yep, I finally happened upon an underground PVC valve near the house that turns on water to this pipe. Funny thing is that this valve is further away then the hose bib next to the pool. It's much easier to just throw the hose in the pool and turn on the water!

...but now I have a thought ... if I can put this PVC valve on a timer perhaps I can automate adding a certain amount of water each week to compensate for evaporation...
I also have a leak that I need to compensate for... that's on my to do list (see lots of air while pump is running... confirmed with bucket test recommended by TFP)... I've been carefully measuring the loss and estimate both the evaporation and leak is costing me $20/month so it's not urgent.