New Spa, Foaming, Borates

May 16, 2015
Reading, PA

I have a new spa. 300 gallons. I'm sanitizing with bleach, per the instructions in the sticky. About a week and a half in and the water chemistry remains stable. CH is 150, pH is 7.5, TA is 65. The spa is indoors and covered. I haven't concerned myself with CYA under these circumstances, since it sees so little sunlight, none directly. Should I still bring up the CYA?

I am getting a fair amount of foam when the air is on, and a bit of a "new spa" plastic-y smell. Is that to be expected? Does it decrease over time? Is there anything I can add to help with the foaming?

I'd like to add borates, as long as it doesn't add to the foaming issue. I'm hoping that will help even out the highs and lows of the sanitizer. But maybe I just need to add CYA... Poolmath indicates 18 oz of 20 mule team, plus 8 fl oz of muriatic acid should get it to 50 ppm. Are these gradual additions, or just dump it all in and mix it up? (I don't add borates to my pool, so I have no experience with the process.) I'm also a little concerned because that seems like a lot of stuff (acid, particularly) to add to this small volume of water.

In short, CYA? Borates? Both? Do those calculations look ok?

Thank you in advance! This forum has been a great resource for my pool. I'm hoping it makes spa care just as simple.


Silver Supporter
Jun 18, 2016
SW, Iowa
Even with a new spa it's still a good idea to purge the plumbing with Ahh-Some and make sure everything is good and clean. There may have been some residual stuff in the pipes that might be giving you some problems. You could also raise CH, that may help with the foaming.

Another common cause for foaming is soap not getting thoroughly rinsed from suits or skin, hair care products, cosmetics, deodorant and such. We have swimwear that we use only in the hot tub and it gets hung up to dry and we never run it through the laundry. A quick hop in the shower before use can keep a lot of these contaminants out of your tub.

You definitely want some CYA in the tub, that will help to buffer the harshness chlorine. Even though is usually covered, my tub does not seem to hold FC as well if CYA gets low. I keep CYA in my tub at about 40ppm and I have seen it fall off, even though I rarely add water. I check it every couple weeks, if I notice it getting low I just use dichlor for a day or two to bring it back up.

Adding borates is much easier if you just get some granular boric acid. Adding this way does not cause a rise in PH so it doesn't require acid to counteract. Cost difference is minimal in a hot tub but for my pool it was not only way easier but about $30 cheaper and I had several pounds left over.


LifeTime Supporter
Jun 23, 2011
I personally wouldn't add that much acid all at once... I'd add the borax, test pH, verify if it's off the chart, and add the acid in 2-4 doses, measuring in between. With jets on high, a hot tub mixes pretty quickly so it doesn't take that long.