Spa Chlorinator acting funny

[CesarZambrano]

Hello, I'm new to this site and the only reason I'm here is because I'm relatively new when it comes to pools and just recently started taking it a little more seriously. Hopefully you guys can help me out because like I said I'm not an expert.

Ok, so I have a chlorinator for my spa that uses those 3-inch chlorine tablets that I think is pretty common with most ppols and spas. If I had to guess my chlorinator looks a lot like the Rainbow 320 version. My problem with this thing is my valve doesn't seem to work. I can shut the valve all the way to zero but chlorine will still continue to fill up my spa.

In the morning around 8 am I check up on my Spa and the chlorine level is at a 10ppm or maybe even higher. The past week I have just been neutralizing the chlorine to get it at a zero so by at least 11 am the chlorine level is ok, around 3ppm. I re-check the chlorine level by the end of the day around 4pm and usually it doesn't look so bad.

However like I said this entire time the valve for my chlorinator is at the bare minimum I can reduce it to and chlorine is still filling up my spa. So in 24 hours my chlorine level has gone from zero to at a 10 ppm or a little higher even though the valve has been "turned off".

My question is should I just replace the valve as that what seems to be the problem? And if anyone has experienced this type of issue firsthand a reply would be appreciated.
Thanks a lot for real.

 

[kimkats]

Even if you have the valve turned to off the pucks are sitting in water and dissolving. As such the chlorine and CYA filled water will seep out of the feeder into the spa.

Here is a link to how we care for spas: How do I use Chlorine in my Spa (or pool)?

 

[CesarZambrano]

I figured how to keep my chlorine in check is to just put about 1/2 or 1/4 a tab in my chlorinator instead of a full tab. A pool service guy told me that one puck is made for 10,000 gallons of water and considering my spa is only 1,000 gallons I should break down the puck to about 1/2 or 1/4 its original size and let it go from there. My vavle is still only open to the lowest degree but this method is working as it is keeping my chlorine level in check. I am no longer getting a 10ppm reading every morning as I have been for a couple weeks now. In terms of my CYA level I'm thinking of just draining my spa once a week or something like that to keep it in balance.

HOWEVER, another problem has arisen. I have just now been realizing that my PH is not being stable. Every morning I've been lowering the PH with some sodium bisulfate to get it at around 7.4. And it works but this whole time I've been concerned with the chlorine I've failed to notice the same thing was happening to my PH.

My alkinity is usually around a 70 and I like to bump it up to around a 90 from time to time. So on average my alkinity level stays within 50-90 range. That ain't so bad to my judgement, however this last friday I tested my water right before leaving and it was around 8ppm or maybe even higher. I don't understand what is happening here? How did my PH jump from 7.4ppm to 8ppm in a matter of hours when all I did to it was lower it just that morning.

I'm still in the process of achieving water balance but I would like to know what is happening with my PH? I am not able to check up on this spa on the weekends so knowing it can jump like this within a couple hours is concerning to me.

 

[jseyfert3]

Welcome to TFP! This site has a lot of great info, and a lot of that isn't understood by the pool industry in general. There's a bit of a learning curve, but once you get that, it really is trouble free. Just realize trouble free isn't maintenance free, but the maintenance isn't hard.

I figured how to keep my chlorine in check is to just put about 1/2 or 1/4 a tab in my chlorinator instead of a full tab. A pool service guy told me that one puck is made for 10,000 gallons of water and considering my spa is only 1,000 gallons I should break down the puck to about 1/2 or 1/4 its original size and let it go from there. My vavle is still only open to the lowest degree but this method is working as it is keeping my chlorine level in check. I am no longer getting a 10ppm reading every morning as I have been for a couple weeks now. In terms of my CYA level I'm thinking of just draining my spa once a week or something like that to keep it in balance.

First off, if you haven't seen already, tablets are frowned upon around here because they add CYA. Some CYA is good, as it keeps chlorine from breaking down as fast, but it also reduces the effectiveness of chlorine. Hence a little known fact (outside of this site) that the proper free chlorine (FC) level depends on the level of CYA. At the low end of recommended CYA range (30 ppm) the target is 4-6 ppm FC, while at the high end of CYA range (60 ppm) the target FC is 7-9. So if you try to use a tablet to maintain FC, you have to constantly test CYA and constantly adjust your target FC level to match. Lots of extra work there. Plus it leads into...

HOWEVER, another problem has arisen. I have just now been realizing that my PH is not being stable. Every morning I've been lowering the PH with some sodium bisulfate to get it at around 7.4. And it works but this whole time I've been concerned with the chlorine I've failed to notice the same thing was happening to my PH.

My alkinity is usually around a 70 and I like to bump it up to around a 90 from time to time. So on average my alkinity level stays within 50-90 range. That ain't so bad to my judgement, however this last friday I tested my water right before leaving and it was around 8ppm or maybe even higher. I don't understand what is happening here? How did my PH jump from 7.4ppm to 8ppm in a matter of hours when all I did to it was lower it just that morning.

I'm still in the process of achieving water balance but I would like to know what is happening with my PH? I am not able to check up on this spa on the weekends so knowing it can jump like this within a couple hours is concerning to me.

...water balance. You can't exactly maintain water balance if you're constantly dumping it. Every time you dump, you have to re-balance. So, first off, sodium bisulfate. Sodium bisulfate isn't recommended for general usage as the sulfates that build up in the water tend to damage metal parts over time, especially stuff like heaters. Muriatic acid is therefore the recommended go-to for pH and TA adjustment.

pH and TA are interrelated through several chemistry equations, which I won't get into, but it is important to note that those equations involve carbon dioxide (CO2). If you have a high TA, you'll end up with high CO2 in the water, and when you aerate (spas are really good at aeration with all the bubbles), you drive that off, which yanks the pH up. This aeration/TA/pH interrelation is why a pool, with little aeration, tends to drift up in pH very slowly over time, which is kept down with acid additions, but a spa will literally skyrocket in pH in a matter of hours or less, as you've seen.

The good news is you can control the pH rise, and make it pretty darn stable. You do this by controlling the TA. Rather than setting it to some arbitrary number, you adjust it until you stop getting pH climb. Typically, for most people, this is around the 50 ppm mark, but it depends on exactly what is in your water and to a lesser extent how much aeration you have. But in general you shoot for 50 to start, then adjust slightly up or down as needed to keep your pH happy at the level you want it to be. The process to lower TA is outlined here, but in short you add acid to target a lower to a target of around 7-7.2, then aerate to raise pH, and repeat until your TA is at your target level. To find out how much acid to add, use PoolMath.

Once you get your pH stable, I'm sure you'll decide that you don't want to dump your water on a regular basis, since depending on your source water this can be a mild PITA. For example, my source TA is over 250, which requires about 18 oz of 32% muriatic acid to be added, split over 6-7 additions (so the pH doesn't drop too far and damage my heater), with aeration between each addition. I'd pack up my spa if I had to do that every week, but since I have to do it once and my pH is almost rock solid for months, it's not a big deal.

If you don't dump water, you can't use chlorine tabs. Liquid chlorine (bleach, liquid shock) is often used, but has to be added every day or every other day because the heat drives off the chlorine so fast. If you can't do that, or don't want to, you can consider bromine. I'm not a bromine expert, and it's slightly more complicated (IMO), but you can use a floater in conjunction with bromine to help maintain levels in between manual additions...of chlorine, believe it or not. (That's partially why I just went straight chlorine, myself) If your spa is next to your pool, and splashing or people go between the two, you can also track bromine into your pool, which leads to other issues.

So, bromine is one option to avoid daily additions of chlorine. The other two are using a small pump to pump liquid chlorine into the spa to maintain a background dose (you still have to manually add after/during each use), or a salt-water generator (SWG), which will again maintain the background dose, and still need an addition after/during each use.

Oh, if your spa cools down between uses, you may be able to get away with longer additions between adding chlorine, but I have no experience with that because my dinky little inflatable spa heats so slowly it would take days to heat up after cooling down, so it's always hot.

Hopefully you made it through there and I didn't scare you away from the site! I'm happy to help explain more, or point you to some of the excellent resources here to help you get going with the TFP method.

 

[CesarZambrano]

My question is why are we aiming for a 50 ppm total alkalinity level when the recommended range is 80-120 ppm? I have heard that keeping a LOW Total Alkalinity level will give you a LOW PH level and a HIGH Total Alkalinity level will give you a HIGH PH level.
Shouldn't the PH and Alkalinity balance be set at their ideal levels and things will be fine. But of course you have aeration rising your PH, but isn't that where Alkalinity comes into play?
I don't understand.

 

[jseyfert3]

Yes, you're right. Higher TA means higher pH, once things equilibriate. In a spa, things equilibriate really fast, and 50 ppm TA (roughly) will give you a pH around 7.4-7.6.

Your spa instructions may list a higher TA, they all do, but if you try to maintain that high TA you'll be adding acid, then TA booster, then acid, then TA booster (we see people doing this all the time). So you drop the TA till the pH is stable. And that happens to be around 50 ppm of TA.

Hopefully this makes sense. I saw this right before I went to bed and popped out a reply quick.

 

[jseyfert3]

Oh, that range might have to do with the fact that they expect you to use dichlor or trichlor, both of which are acidic, so a higher TA may help keep proper pH in that case. I say might and may because most manufacturer recommendations don't really line up to values that work

 

[Chris19D]

Welcome to TFP! This site has a lot of great info, and a lot of that isn't understood by the pool industry in general. There's a bit of a learning curve, but once you get that, it really is trouble free. Just realize trouble free isn't maintenance free, but the maintenance isn't hard.


First off, if you haven't seen already, tablets are frowned upon around here because they add CYA. Some CYA is good, as it keeps chlorine from breaking down as fast, but it also reduces the effectiveness of chlorine. Hence a little known fact (outside of this site) that the proper free chlorine (FC) level depends on the level of CYA. At the low end of recommended CYA range (30 ppm) the target is 4-6 ppm FC, while at the high end of CYA range (60 ppm) the target FC is 7-9. So if you try to use a tablet to maintain FC, you have to constantly test CYA and constantly adjust your target FC level to match. Lots of extra work there. Plus it leads into...


...water balance. You can't exactly maintain water balance if you're constantly dumping it. Every time you dump, you have to re-balance. So, first off, sodium bisulfate. Sodium bisulfate isn't recommended for general usage as the sulfates that build up in the water tend to damage metal parts over time, especially stuff like heaters. Muriatic acid is therefore the recommended go-to for pH and TA adjustment.

pH and TA are interrelated through several chemistry equations, which I won't get into, but it is important to note that those equations involve carbon dioxide (CO2). If you have a high TA, you'll end up with high CO2 in the water, and when you aerate (spas are really good at aeration with all the bubbles), you drive that off, which yanks the pH up. This aeration/TA/pH interrelation is why a pool, with little aeration, tends to drift up in pH very slowly over time, which is kept down with acid additions, but a spa will literally skyrocket in pH in a matter of hours or less, as you've seen.

The good news is you can control the pH rise, and make it pretty darn stable. You do this by controlling the TA. Rather than setting it to some arbitrary number, you adjust it until you stop getting pH climb. Typically, for most people, this is around the 50 ppm mark, but it depends on exactly what is in your water and to a lesser extent how much aeration you have. But in general you shoot for 50 to start, then adjust slightly up or down as needed to keep your pH happy at the level you want it to be. The process to lower TA is outlined here, but in short you add acid to target a lower to a target of around 7-7.2, then aerate to raise pH, and repeat until your TA is at your target level. To find out how much acid to add, use PoolMath.

Once you get your pH stable, I'm sure you'll decide that you don't want to dump your water on a regular basis, since depending on your source water this can be a mild PITA. For example, my source TA is over 250, which requires about 18 oz of 32% muriatic acid to be added, split over 6-7 additions (so the pH doesn't drop too far and damage my heater), with aeration between each addition. I'd pack up my spa if I had to do that every week, but since I have to do it once and my pH is almost rock solid for months, it's not a big deal.

If you don't dump water, you can't use chlorine tabs. Liquid chlorine (bleach, liquid shock) is often used, but has to be added every day or every other day because the heat drives off the chlorine so fast. If you can't do that, or don't want to, you can consider bromine. I'm not a bromine expert, and it's slightly more complicated (IMO), but you can use a floater in conjunction with bromine to help maintain levels in between manual additions...of chlorine, believe it or not. (That's partially why I just went straight chlorine, myself) If your spa is next to your pool, and splashing or people go between the two, you can also track bromine into your pool, which leads to other issues.

So, bromine is one option to avoid daily additions of chlorine. The other two are using a small pump to pump liquid chlorine into the spa to maintain a background dose (you still have to manually add after/during each use), or a salt-water generator (SWG), which will again maintain the background dose, and still need an addition after/during each use.

Oh, if your spa cools down between uses, you may be able to get away with longer additions between adding chlorine, but I have no experience with that because my dinky little inflatable spa heats so slowly it would take days to heat up after cooling down, so it's always hot.

Hopefully you made it through there and I didn't scare you away from the site! I'm happy to help explain more, or point you to some of the excellent resources here to help you get going with the TFP method.

That was a great and very helpful post, jseyfert3!

 

[CesarZambrano]

I understood what you meant by getting the alkalinity at something like 50 ppm and that somehow keeps the PH stable. That's fine. But it seems counter-intuitive when everything says keep an 80-120 range.
I'm still in the process of all of this but I thank you for the reply.

 

[kimkats]

Cesar, These are all suggested RANGES for the AVERAGE pool. Some pools/areas will be on the down side of average, some will be on the upside. What we try for is what works for YOUR pool and area. There are so many factors that come into play from amount of sun, dirt, swimmer load, etc. that it is almost impossible to say "keep this at x level and all will be good". Work with your numbers and see what your pool likes. You will know it is happy when the levels are stable for a couple/few days in a row.

Kim

 

[jseyfert3]

A pool has a lot less aeration than a spa, so a higher TA is called for. That may also be where some of the 80-120 ppm comes from. But for a spa, it's closer to 50.