Newbie needs help with spa water chemistry problems

[Vesuvius]

A drape over swg (like the saltron mini or controlomatic) will handle the standby chlorination whether you’re home or not. Trichlor dissolves too rapidly in a hot tub & will raise fc & lower ph too much- this can damage surfaces & equipment like heater, cover & headrests.

Thanks, I've bought a Saltron Mini and will do a drain/re-fill with Ahh-some as soon as it arrives. Looking forward to a fresh start with all this good advice!

 

[Vesuvius]

I've been going through the awesome Pool School stuff and trying to convert the advice to spa usage wherever possible, but I'm confused on the Chlorine/CYA chart:

Chlorine / CYA Chart

The CYA recommendation for SWG pools is much higher than for liquid chlorine yet it does say 20-30 ppm for indoor pools. So, for an outdoor spa that's used mostly at night, with a drape-over SWG for FC maintenance but using liquid chlorine for FC replacement after soaks, what should I target for CYA, minimum FC and target FC?

Thanks!

 

[ajw22]

CYA of 30-50 is fine as described in…

How do I use Chlorine in my Spa or Hot Tub?

If you have a question about any information within this Sticky, please start a new thread for yourself where you will receive very quick responses to your specific questions. Thank you! Introduction There are two main things to consider when maintaining your hot tub water, Water Balance and...

www.troublefreepool.com

Follow the FC/CYA Levels for your CYA level and keep your FC on the high side. Spas consume chlorine rapidly.

 

[Vesuvius]

CYA of 30-50 is fine as described in…

How do I use Chlorine in my Spa or Hot Tub?

If you have a question about any information within this Sticky, please start a new thread for yourself where you will receive very quick responses to your specific questions. Thank you! Introduction There are two main things to consider when maintaining your hot tub water, Water Balance and...

www.troublefreepool.com

Follow the FC/CYA Levels for your CYA level and keep your FC on the high side. Spas consume chlorine rapidly.

Thanks. I'd read that post (several times) but Nitro is describing a non-SWG scenario and the chart indicates a much higher level (for reasons I don't understand) for pool SWG scenarios, so I'm trying to see if the SWG addition changes Nitro's recommendation.

And, regarding the chart, I'm not sure which min FC and target FC to use, given the SWG. For example, 60 CYA in a liquid chlorine pool calls for 5 and 7-9 FC, whereas the same 60 CYA in a SWG pool calls for 3 and 4.

 

[ajw22]

As I said, hot tubs consume chlorine rapidly when in use. I would use a target of 7-9 rather then 4.

 

[Mdragger88]

Thanks again. This may be a dumb question, but how can you tell if no more detritus is released if there is a large amount of it from a previous round that was not drained out and cleaned up?

Sorry, missed your post-
You clean it out as you go (wiping the walls where it collects & scooping out the dirty foam) it’s a process that requires your attentiveness. You don’t want the “goo” to dry on the walls of the spa.
when you’re current round of foam subsides add a 1/2 dose & go again repeating the process until it stops producing funky stuff.

 

[Mdragger88]

Thanks, I've bought a Saltron Mini and will do a drain/re-fill with Ahh-some as soon as it arrives. Looking forward to a fresh start with all this good advice!

Don’t forget to follow the guide upon refill

How do I use Chlorine in my Spa or Hot Tub?

If you have a question about any information within this Sticky, please start a new thread for yourself where you will receive very quick responses to your specific questions. Thank you! Introduction There are two main things to consider when maintaining your hot tub water, Water Balance and...

www.troublefreepool.com

 

[Vesuvius]

Sorry, missed your post-
You clean it out as you go (wiping the walls where it collects & scooping out the dirty foam) it’s a process that requires your attentiveness. You don’t want the “goo” to dry on the walls of the spa.
when you’re current round of foam subsides add a 1/2 dose & go again repeating the process until it stops producing funky stuff.

No worries and thanks--this is perfect. Will follow this approach. Interested to see how much funky stuff will show up.

 

[Vesuvius]

Don’t forget to follow the guide upon refill

How do I use Chlorine in my Spa or Hot Tub?

If you have a question about any information within this Sticky, please start a new thread for yourself where you will receive very quick responses to your specific questions. Thank you! Introduction There are two main things to consider when maintaining your hot tub water, Water Balance and...

www.troublefreepool.com

I will! The guide advises shocking to 12 FC weekly but I've read elsewhere here that shocking is unnecessary if adequate FC levels are maintained at all times. Do you have a view on that?

I do have a separate post asking about how to adapt (if at all) the guide to a SWG system (as the guide describes a liquid chlorine approach), given that the Pool School Chlorine/CYA Chart makes different CYA, min FC and target FC recommendations for SWG vs. liquid chlorine pools. Here's the link to that thread:

How to use the Chlorine/CYA chart for a spa using SWG?

Any thoughts you have on that topic would be great as well--thanks!

 

[Mdragger88]

The guide advises shocking to 12 FC weekly but I've read elsewhere here that shocking is unnecessary if adequate FC levels are maintained at all times. Do you have a view on that?

Note* The 12ppm shock level mentioned in the guide is based on an assumed cya level of 30ppm - if your cya differs then your shock/slam level differs- ALWAYS follow the
FC/CYA Levels.

Here’s the deal,
You should generally raise fc to slam level for some reason, not just because it’s Tuesday or whatever. It won’t hurt to do this on some regimented schedule but it’s not always really necessary if adequate fc levels are always maintained.
Here are the reasons to raise fc to slam level in a spa

* elevated cc’s (above .5)
* cloudy or green water
*High bather load/bather waste that will rapidly consume lower fc levels before dosing again.
Most here dose to or near slam level for their cya after using the tub to ensure they have enough fc to oxidize current bather waste & to make it without broaching minimum before their next test/dose/use. YMMV.

That guide is quite old (written 15 yrs ago) & could stand to be redone a little but it’s the best all in one chlorine spa primer we’ve got currently.

About the swg, since it just hangs down into the water instead of all the water flowing through it at some point I stick to the liquid chlorine side of the fc/cya chart.
The swg is mainly there to handle standby chlorination needs. Not heavy bather loads. For those you will still need to dose with liquid chlorine.
I find in my small tub that if I turn the swg up high enough to makeup for all the fc needs when in use then in the idle/stand by time the fc gets too high. Once again YMMV- testing frequently will help you find your happy place.
As I mentioned above, the guide needs a little work over, I thought of coining the term “the dichlor then bleach &/ swg method” but it seems a bit cumbersome & hasn’t quite stuck yet

 

[Vesuvius]

Note* The 12ppm shock level mentioned in the guide is based on an assumed cya level of 30ppm - if your cya differs then your shock/slam level differs- ALWAYS follow the
FC/CYA Levels.

Here’s the deal,
You should generally raise fc to slam level for some reason, not just because it’s Tuesday or whatever. It won’t hurt to do this on some regimented schedule but it’s not always really necessary if adequate fc levels are always maintained.
Here are the reasons to raise fc to slam level in a spa

* elevated cc’s (above .5)
* cloudy or green water
*High bather load/bather waste that will rapidly consume lower fc levels before dosing again.
Most here dose to or near slam level for their cya after using the tub to ensure they have enough fc to oxidize current bather waste & to make it without broaching minimum before their next test/dose/use. YMMV.

That guide is quite old (written 15 yrs ago) & could stand to be redone a little but it’s the best all in one chlorine spa primer we’ve got currently.

About the swg, since it just hangs down into the water instead of all the water flowing through it at some point I stick to the liquid chlorine side of the fc/cya chart.
The swg is mainly there to handle standby chlorination needs. Not heavy bather loads. For those you will still need to dose with liquid chlorine.
I find in my small tub that if I turn the swg up high enough to makeup for all the fc needs when in use then in the idle/stand by time the fc gets too high. Once again YMMV- testing frequently will help you find your happy place.
As I mentioned above, the guide needs a little work over, I thought of coining the term “the dichlor then bleach &/ swg method” but it seems a bit cumbersome & hasn’t quite stuck yet

This is exactly what I was looking for--many thanks for this. Now I finally feel ready to take this on. Plan is to drain on Saturday...

 

[Mdragger88]

This is exactly what I was looking for--many thanks for this. Now I finally feel ready to take this on. Plan is to drain on Saturday...

You definitely got this
Heck, I’m just a mom from Eudora, Ms & I figured it out
Let us know how the purge goes- some people are extremely surprised at what comes out the 1st time!
& Don’t hesitate to ask questions- somebody’s always around here.

 

[Vesuvius]

I'm preparing to drain/fill and begin using a Saltron Mini SWG and wondering how people adjust the Chlorine spa recommendations here when using a SWG:

Nitro's Approach To Water Maintaince

Using Pool Math, if I plug in the recommended 7.4 pH, 50 TA, 150 CH, 30 CYA, 100 F temp, 50 Borate and 2000 Salt, I get -0.73 CSI. Just playing around with the calculator, it appears the best option to get close to 0.0 CSI is to take pH up to 7.6 and TA up to 100, which results in a -0.17 CSI. This is obviously dramatically higher TA than recommended in the guide--am I missing something? Thanks!

 

[Mdragger88]

If you’re spa isn’t plaster a slightly negative csi is ok. Negative Csi really pertains to plaster, stone, & pebble corrosion not metal corrosion.
You just don’t want it too positive & have scaling problems as that can affect your heater, swg & shell in all pools.
The ph will likely hover around the high 7’s anyway- even with ta of 50 & borates added.
As far as fc goes I stick with the chlorine side of the
FC/CYA Levels since the water isn’t all really being run through the cell & the bather load is so high in a spa.

We have the same guide pinned to the top of this subforum & as far as I can tell it still reads the same.

How do I use Chlorine in my Spa or Hot Tub?

If you have a question about any information within this Sticky, please start a new thread for yourself where you will receive very quick responses to your specific questions. Thank you! Introduction There are two main things to consider when maintaining your hot tub water, Water Balance and...

www.troublefreepool.com

There have been some slightly divergent views between this forum & that one over the years so keep in mind that all the information you find there may not be fully accepted here. That forum isn’t as actively moderated/monitored as tfp & they aren’t affiliated although many original contributors are the same.

 

[Methuselah]

After your drain and refill please note that testing should be daily, at least at first. You need to see predictable behavior before stretching that interval. Daily can become every other day, then longer, but take a long soak or throw a hot tub party, it's either back to daily or risk a repeat of what you are going through now...

It won't take you long to get the hang of it, but there's no such thing as a maintenance free hot tub.

Sorry if I come off preachy.

Maybe the next hurdle is how long before you dump again? I'll give you one experts point of view...

Is weekly shock needed?

As per the spa sticky thread: "Never let FC drop to Zero for any length of time. Keep it between 3-6 ppm normally, min of 1 ppm, and shock to 12 ppm once a week." If my CC is 0.5 or less, do I need to shock once a week? thanks!

www.troublefreepool.com

 

[Methuselah]

The SWG water chemistry is not familiar to me, but there's lots of expert advice here

I do know that you should not add borites until you get the rest of the water chemistry where you want it first. The lower your TA the less tendency your ph will shoot up (again though, with a SWG I'm clueless...).

 

[Vesuvius]

If you’re spa isn’t plaster a slightly negative csi is ok. Negative Csi really pertains to plaster, stone, & pebble corrosion not metal corrosion.
You just don’t want it too positive & have scaling problems as that can affect your heater, swg & shell in all pools.
The ph will likely hover around the high 7’s anyway- even with ta of 50 & borates added.
As far as fc goes I stick with the chlorine side of the
FC/CYA Levels since the water isn’t all really being run through the cell & the bather load is so high in a spa.

We have the same guide pinned to the top of this subforum & as far as I can tell it still reads the same.

How do I use Chlorine in my Spa or Hot Tub?

If you have a question about any information within this Sticky, please start a new thread for yourself where you will receive very quick responses to your specific questions. Thank you! Introduction There are two main things to consider when maintaining your hot tub water, Water Balance and...

www.troublefreepool.com

There have been some slightly divergent views between this forum & that one over the years so keep in mind that all the information you find there may not be fully accepted here. That forum isn’t as actively moderated/monitored as tfp & they aren’t affiliated although many original contributors are the same.

Thanks! Is there a limit to how low you’d let the CSI go in a fiberglass spa?

 

[ajw22]

Thanks! Is there a limit to how low you’d let the CSI go in a fiberglass spa?

No

 

[duraleigh]

I would disregard CSI in a fiberglas or vinyl pool.

 

[Vesuvius]

I've seen recommendations for pools but assuming it's shorter for spas, given how much less time it takes for full circulation. What's the rule of thumb? Thanks!