Greetings from Phoenix!

[spanman]

Hello, everyone--

We have a 1,000 gallon in-ground spa, lined with tile, about 20-years old with recently upgraded pumps, controls and heater. I had been mainly using 1" trichlor, with a drain-and-refill every one to two years. Having read through much of Pool School over the last week I'm inclined to switch to bleach, with the understanding that I'll have to closely monitor pH which will be driven upward by liquid chlorine.

Although the water clarity is currently good and FC levels are constant, I have had algae blooms in the past that have left some surfaces (mainly the vertical surfaces) with hard-to-remove stains. Super-chlorinating and brushing with either nylon or stainless wire brush heads doesn't touch them. I've had some success with heavy-duty synthetic scrubbing pads, but it's a lot of work. Any suggestions are welcome!

Don

 

[Texas Splash]

Hi Don and welcome! Spend some time to get to know our site, and if you haven't seen it already, take a look at this: How do I use Chlorine in my Spa (or pool)?. We look at bleach as pH-neutral because after dispensed and oxidized, the body of water goes back to its original pH. However, being a user of tabs which are acidic, they probably helped to keep that pH down as well. I suspect period drains may have help with the hard water as well. In any case, lots of folks here happy to help answer any questions for you. Let us know. Have a good evening,

 

[spanman]

....We look at bleach as pH-neutral because after dispensed and oxidized, the body of water goes back to its original pH....

Thanks for the great info! I never knew that pH would return to pre-treatment levels once the FC dropped as well. But I’m guessing I’ll be saying “I never knew that” a lot as I peruse TFP.

 

[PoolGate]

I would treat that as a seasonal/temporary pool. See below.

Trouble Free Pool

 

[mknauss]

Do you cover the spa when not in use or do you just not heat it?

 

[Arizonarob]

Alright, another Valley dweller. Welcome Don.

 

[spanman]

Do you cover the spa when not in use or do you just not heat it?

We don’t cover it. It’s not heated when not in use, but the filter pump runs daily.

 

[mknauss]

We don’t cover it. It’s not heated when not in use, but the filter pump runs daily.

Then you have a choice. You could run it as a temporary pool as PoolGate stated or fill out your test kit with the FAS-DPD test and run as a permanent pool. If temporary, plan to drain and refill every couple months. You need the accuracy of the FAS-DPD test to properly manage your FC. And once your CYA gets to 50 ppm or so, you do need to switch to liquid chlorine adding daily. With that small of a water volume, you will have to be very careful about your FC dropping below minimum as shown on the FC/CYA chart