Spa vs Pool Chlorine - Algae

[FlGator68]

Hello, I’m still a relatively new DIY pool owner (couple of years) and I’ve noticed that my spa always grows algae much earlier than the pool. I decided to test them today and the pool is at the target ppm and the spa is much less.
I have a SWG and I have the spa feed valve set to max and the pool return valve dialed back some (in order to get my spillover to work well). If anything I thought this setting would benefit the spa more but it clearly is not. Pool returns on the floor. Any tips on how to get equal chlorine into the spa with a SWG? Picture attached for reference. Thank you!

 

[JJ_Tex]

Interesting. Can you post a picture of your equipment pad?

 

[FlGator68]

Interesting. Can you post a picture of your equipment pad?

Yes, absolutely, thank you for the reply.. see attached.

 

[ajw22]

What speed are you running your pump?

What automation system do you have? iAqualink?

What was the FC in your pool and spa?

Post a complete set of test results.

 

[FlGator68]

What speed are you running your pump?

What automation system do you have? iAqualink?

What was the FC in your pool and spa?

Post a complete set of test results.

I run the pump at 2250rpm during the day which turns the whole pool over 4 times a day.
I use iAquaLink.
I’ll have to run the full results, I just used a quick test strip to see the difference between the two. Attached are my results in the main pool from the weekend.. I’ll have to again for both pool and spa. Based on the test strip the spa chlorine seems to be around 2-3ppm.

 

[ajw22]

Turnovers are meaningless.

Turnover of Pool Water - Further Reading

www.troublefreepool.com

Test strips should be trashed.

Your spa should have the same water flow as your pool. How vigorous is the spillover and flow from spa to pool?

 

[FlGator68]

Turnovers are meaningless.

Turnover of Pool Water - Further Reading

www.troublefreepool.com

Test strips should be trashed.

Your spa should have the same water flow as your pool. How vigorous is the spillover and flow from spa to pool?

The spillover is very minimal at 2250rpm which is about 55gpm. It only really gets vigorous at 3000rpm or higher which is close to full speed.
You can see by my valve picture that I have already dialed back the main returns to direct more to the spa but that only results in what I just described. I’m not sure if it is okay to dial those back further to better balance the spa flow?
I run it lower rpm all day to save power but also to reduce wear on the pump over time. Running it in the 3,000s seems to negate the value of a VSP. I’m wondering if balancing valves is a viable alternative?

 

[ajw22]

You are headed in the wrong direction with your thinking. Please do some diagnostics for me.

If you close the pool return valve almost completely how vigorous is the spa overflow?

Then backoff on closing the pool return valve and what position is needed to get an acceptable spa spillover?

Your problem is you have a 1.65 HP pump and not a 3+ HP pump. Any pool with a spa that shares a pump should have a 3 HP pump. 2250 RPM does not give you as much flow with your 1.65 HP pump as it would with a 3 HP pump. You have to run your pump at a faster RPM to get the equivalent flow.

What makes you believe that 2250 rpm is giving you 55GPM of flow?

You really should be using the SPILLOVER mode on your Aqualink to refresh your spa water two or threee times a day and not run your spa waterfall continuously. During the 15 minute SPILLOVER periods you ramp up your pump and refresh all the spa water with fresh pool water. That way you run your VSP at high speed for a few 15 minute periods and can run it at a lower speed the rest of the time.

To turn on SPILLOVER mode you need to turn on DIP Switch 3 on your Aqualink as described in Jandy Aqualink RS - Further Reading

 

[FlGator68]

You are headed in the wrong direction with your thinking. Please do some diagnostics for me.

If you close the pool return valve almost completely how vigorous is the spa overflow?

Then backoff on closing the pool return valve and what position is needed to get an acceptable spa spillover?

Your problem is you have a 1.65 HP pump and not a 3+ HP pump. Any pool with a spa that shares a pump should have a 3 HP pump. 2250 RPM does not give you as much flow with your 1.65 HP pump as it would with a 3 HP pump. You have to run your pump at a faster RPM to get the equivalent flow.

What makes you believe that 2250 rpm is giving you 55GPM of flow?

You really should be using the SPILLOVER mode on your Aqualink to refresh your spa water two or threee times a day and not run your spa waterfall continuously. During the 15 minute SPILLOVER periods you ramp up your pump and refresh all the spa water with fresh pool water. That way you run your VSP at high speed for a few 15 minute periods and can run it at a lower speed the rest of the time.

To turn on SPILLOVER mode you need to turn on DIP Switch 3 on your Aqualink as described in Jandy Aqualink RS - Further Reading

Great questions and advice! I have a FlowVis flow meter and I just confirmed it’s 55gpm at 2250rpm.
I did your tests and with return valve all the way off the spillover is max flow, like over the top. I reopened the return valve and at half open I still have a vigorous, albeit not perfectly uniform, but definitely vigorous spillover. See attached pics. I can try spillover mode (new to me) but wanted to send this first.

 

[ajw22]

I reopened the return valve and at half open I still have a vigorous, albeit not perfectly uniform, but definitely vigorous spillover.

So see if your spa stays equally chlorinated with the pool with that valve settings and flow.

Getting the spillover uniform is not the objective.

 

[FlGator68]

So see if your spa stays equally chlorinated with the pool with that valve settings and flow.

Getting the spillover uniform is not the objective.

This solved it, so simple but couldn’t figure it out without your help. Thank you!