Hot Tub and Taylor Test Kit

[bymyhandP]

Hello,

I have had a pool for about 10 years and been using the Taylor test kit (K-2006) for a majority of those years. I feel quite versed in how it works and have a really good process setup with my pool. Though, I recently got a SWG hot tub that is about 450 gal and I have been having a really hard time with the PH test in the Taylor test kit.

When I fill the hot tub from the tap and balance the water, everything is great. I rarely have to add chems to balance the water. My hardness is a bit low but still within range. Though as soon as the water is up to operating temperature 102, the PH goes through the roof. When I check with the strips everything looks fine. I then go about the process of battling the PH/ALK relationship trying to lower one without destroying the other. Once I finally get this to a place that fits within both ranges, the strip now report a PH of under 7(I think because the strip are a bit hard to read).

All of the other tests are spot on, it is just the PH test that is causing me issues. Does anyone know if I need to test the hot tub differently using this test kit?

 

[CuckooChris]

I'm confused, are you using the K-2006 or test strips? Post a set of results using the K-2006 kit.

 

[bymyhandP]

Hello, I have both, since the test strips came with the hot tub and I had the K-2006 from owning my pool.

After refill, before temp rise:
Test strip: 7.4 (ish, since the test strips are hard to read)
K-2006: 7.4

After temp rise to 102:
Test strip: 7.4 (ish, since the test strips are hard to read)
K-2006: 8+ with an acid demand of 1 (Which is also odd IMO)

I haven't done this with my latest fill up, but typically 1 acid demand will actually drop it from 8+ to below 7.4.

 

[CuckooChris]

Hello, I have both, since the test strips came with the hot tub and I had the K-2006 from owning my pool.

After refill, before temp rise:
Test strip: 7.4 (ish, since the test strips are hard to read)
K-2006: 7.4

After temp rise to 102:
Test strip: 7.4 (ish, since the test strips are hard to read)
K-2006: 8+ with an acid demand of 1 (Which is also odd IMO)

I haven't done this with my latest fill up, but typically 1 acid demand will actually drop it from 8+ to below 7.4.

Do you happen to know your TA using the K-2006?

 

[Krulligo]

Yes knowing TA would help. Also did you add borates?. So from what I see, you filled the water. When cold you measures 7.4 with Taylor. Then you did nothing other than waiting for water to heat up and remeasures 8 with Taylor?

During the heating process, did you have aeration going, any cycles, circulation pump etc? I am assuming you did. Depending one how fast your heating process took and during that time if your cycles were on then aeration can easily raise your pH in such a small body of water. That is what happens to me when I refill and heat. Especially on the higher side of TA

 

[bymyhandP]

TA Is 80 after fill and the same after temp rise. My hot tub has a circulation pump so I only turn on the main pumps when I add the salt and the granular choline. From what I have noticed, the TA is rock solid, it just moves when I use chemicals to lower the PH. Also I don't use borates and I do nothing but follow the process below between tests. The heating process takes about 12 to 24 hours. I do add the optional sliver ion cartridge.

I follow this process:

 

[CuckooChris]

Not sure what you're using to lower PH, but muriatic acid is recommended here to lower PH. With a TA of 80, I wouldn't worry about TA right now and just use MA to lower your PH. Use can use pool math to calculate how much to add. I rarely test my TA and just keep my PH in range. To do that, my TA is around 40-50. There is a ton of great info in the forum and it's not just a forum to ask questions, there are proven systems to easily balance and sanitize your water. With any hot tub, even new ones, it's highly recommended to do an Ahh-some purge.