Is my treatment routine reasonable?

[jkinsley]

I have a 17,000 gallon, plaster lined, salt water pool with chlorine generator in San Diego. Recent Taylor test results:
pH 7.5 (target 7.5)
FC 6 (target 6)
CC 0
TA 50 (target 60)
CH 700 and continually climbing
CYA 50 (target 60)
Salt 3500 (target 3300)

I fired my pool guy two years ago and have since been doing my own maintenance. I have found the following quasi-stable routine:
I add muriatic acid to maintain pH of 7.5. I installed an automatic acid feeder and have it dialed in so my pH hardly varies.
I add baking soda every couple weeks to maintain TA of 40-60. The muriatic acid is always causing it to drop.
I keep my chlorine generator output set to 100%, and adjust the total daily pool runtime to maintain FC around 6. In June this requires ~8 hours of runtime per day. In December it requires ~2 hours per day.

I need to change the water out every 2-3 years to keep CH down. Our tap water is pretty hard, and CH is always rising due to evaporation and refill.

I ocassionally get algae in the darker corners of the pool. I'm considering raising my FC target to 8 to prevent this.

Does this all seem reasonable? Before getting the automatic acid feeder,my pH was chronically high, and I would get calcium deposits on the plaster walls. Having the near-constant acid additions has solved this, though it requires the frequent baking soda additions.

Thanks for all your help getting to this point!

 

[Newdude]

Hot DANG, J. You have it well thought out. Your pool is telling you what it needs, and you are listening and thinking it out. Bravo.

If you are seeing algae, the FC is dipping and you need more, like you have rationalized.

Many with high CH fill water go with softened water for the pool to not have to drain every 2 to 3 years.

 

[mknauss]

I add baking soda every couple weeks to maintain TA of 40-60. The muriatic acid is always causing it to drop.

The only thing to consider is the above. There is no reason to do that. Adjust your pH set point to 7.8. Also, do you have a constant source of aeration that is making your pH rise?

 

[jkinsley]

Hot DANG, J. You have it well thought out. Your pool is telling you what it needs, and you are listening and thinking it out. Bravo.

Thanks! It's been a process.

The only thing to consider is the above. There is no reason to do that. Adjust your pH set point to 7.8. Also, do you have a constant source of aeration that is making your pH rise?

When my pH is that high I get calcium scaling on the plaster walls. The reason I target pH 7.5 is because Pool Math tells me it gives a slightly negative calcium scaling index.

I do have a source of aeration. There's a spa that shares the pump and chlorinator with the pool. Water spills over a "water feature" in the spa wall into the pool. I have it adjusted to try to keep splashing to a minimum, but I don't know a way to eliminate it.

 

[mknauss]

OK -- do you have automation that you control the spa operations with?

 

[jkinsley]

Yes, the automation works like this:
During normal daily operation, the water is pumped from the pool, and returned to the pool and spa, with the spa spilling into the pool.
During spa operation (only when it's in use) the water is pumped from and returned to the spa only. Automated 3-way valves control this.

 

[mknauss]

What automation do you have? Most all you can schedule a Spillover/Spillway feature. Then schedule that for 20 minutes or so twice a day. Will dramatically reduce your pH rise.

 

[jkinsley]

What automation do you have? Most all you can schedule a Spillover/Spillway feature. Then schedule that for 20 minutes or so twice a day. Will dramatically reduce your pH rise.

It's Pentair EasyTouch.
The way it's plumbed, if the spillway isn't active then no return water is being directed to the spa. Maybe that would be okay for all but 20 minutes? I worry a bit that the spa won't be adequately chlorinated if I do that.

 

[mknauss]

Great. The ET is easy.
Do you have a make up line for the spa returns when in Pool mode or is your Spa return valve actuator partially open to the spa in Pool Mode?

 

[jgofnj]

for the dark corners, do you brush at all. That will make a huge difference with those numbers.

 

[SoCalTFP]

Definitely look into the automation and plumbing. My pool/spa was configured the same way and the spillway was on whenever the pool was on, raising my PH significantly. After enabling the spillway separately and adjusting the valve I can set pool to full runtime and run the spillway for 30 mins a day for water chemistry. It was a little overwhelming to figure out but once I looked at the pad and settings it took less than an hour.

Also look into adding Borates, that could help with PH stability. I’ve also read it helps with PH level buffering inside the SWG which can be much higher than the pool itself. Boric Acid was really easy and cost was reasonable.

 

[jkinsley]

I'll do an experiment and report back. I'll configure it to return no water to the spa except for the last 30 minutes of the day which will effectively shut off the spillway for that time.

 

[mknauss]

I am not sure you understand what we are speaking of. If you can post a few pictures of your equipment pad we can advise on how to set up your system to run in Pool Mode (no spillover) then twice per day for 20-30 minutes to run Spillway to refresh the water in the Spa.

 

[jkinsley]

My equipment schematic looks like the attached diagram from the EasyTouch installation guide.
The valve that controls whether return water goes to the pool or spa is set up so that in spa mode all water is returned to the spa, and in pool mode, some water is returned to the spa, and some to the pool.

I can move the travel limits on this valve so that in pool mode it all returns to the pool, and I've done this.

But I don't see a way to program a "spillway" mode so that intake is from the pool and return is to the spa. What's the best way to do this?

 

[mknauss]

Use a Feature and assign a Circuit Function as Spillway. Then schedule Spillway for the times you wish. You can assign a pump rpm to Spillway.

 

[jkinsley]

Brilliant -- that did the trick. Thank you!