Ace Sanitizing System Issue - little to no chlorine production

[wpbucher]

Hi,

Here are my numbers via my TFT-100 and K-1776:
Temp: 100
FC: 1.5 (was 3.5 two days ago...2.5 yesterday)
PH: 7.4
TA: 50
Borates: 50
CH: 10
Salt: 1400
CYA: 30

My HotSprings Grandee was delivered in Nov 2013. I've been babysitting it ever since. From day one, it never seemed like it produced a sufficient amount of chlorine. I've tried shocking. I've done the Spa System Flush when I changed the water.

I'm a stay-at-home-dad (some days a blessing...some days a curse), so I have time to check the tub every day. I've come to the conclusion that I'm basically performing the dichlor-bleach method in place of the Ace system.

I've read other posts where the output was set too high and people "forgot" to set lower and their spa had very high levels of chlorine. This has NEVER happened to me.

My neighbor has a Grandee that is now 4 years old. He was having problems with rusting jet rings and pumps going bad. He replaced his cell and then the circulation pump started leaking. He asked me to come over while the tech was replacing the pump (neighbor out of town). I spoke to the tech and he just kept saying these thing happen due to "bad water chemistry". I took a sample and tested it. FC was 31 ppm!!! I tested 3 times. I set the size and output to 1. Size was at 8, output was at 1. Upon his return, my neighbor said that the tech had already set the chlorine output to "low". I told him, that to reduce output further the tech should have reduced the size number in addition to the output. I was amazed that the tech did not test the water when he was replacing the pump. This makes me question the competency of the dealer. NOTE: I got my neighbor to invest in a good test kit and recommended TFP.

I have not contacted the dealer because they charge $95 to come out. Even if it is warranty. I'm out of warranty, so that is not a factor. I thought I would try TFP before contacting the dealer.

Anyway, the confusing part is that my spa control panel always reports that everything is fine. Salt level is fine. System is functioning.....everything is OK.

Visual inspection of the chlorine generator in the filter cabinet shows no build up. I can see through the unit and the plates are clean. I tried "cleaning" them per instructions. I dip it and saw absolutely no bubbles...so I removed after about 10 seconds and rinsed.

So what could it be? My spa is newer than my neighbors, so I don't have the size variable.

How does the size variable get set? I'm thinking that perhaps the size variable is set too low for my spa.
Is there a way I can determine this?
Is there a "secret" combination of control buttons that I can press to access the size variable?

My FC is 1.5 today. If I would initiate "boost", I would probably get FC of 2 or 2.5 tomorrow (nobody in spa during boost period). This tells me the unit if producing chlorine...just not very much.

I've attached pictures that might help with a diagnosis.

Any thoughts or suggestions are greatly appreciated.

Thanks TFP!!!

 

[JasonLion]

What is the recommended salt level for your unit?

 

[chem geek]

According to this manual, the minimum salt level is 750 ppm, the maximum is 1500 ppm, and the recommended target is 1000 ppm. This is because the unit uses boron-doped diamond electrodes so produces more hydroxyl radicals so less chlorine production is needed.

According to the manual, you should be able to set the spa size by pressing the Spa Size soft button, but perhaps they set that internally for your particular spa and that you can't change that (your photo of the panel left out the buttons that are below that panel). You aren't supposed to be changing the spa size to control the output level. That is what the Use Level soft button changes.

 

[wpbucher]

I look at the spa size and the output level like the front and rear cogs on a bicycle. For each spa size there is an output range. So, instead of 9 output settings you get (size x output) number of settings. Unfortunately, I can't select a spa size. I turned on boost at 9 am. 6.5 hours later, the FC has increased from 1.5 to 2.5. This is what I've been experiencing. The Ace system produces a little bit of chlorine, but even on boost...it would not be able to handle even a slight bather load without assistance from me dosing with bleach or MPS after a soak.

So that has been the routine. Soak --> dose with bleach or MPS --> watch FC slowly fall (while on output=7) --> when it gets around FC=1, I boost to get it back up to 3.5 or --> watch FC slowly fall (output=7) --> at some point we use the hot tub and the cycle repeats. The spa gets used about once per week. Sessions are typically 4-6 person/hours. Typically, the wife and I in for 2-3 hours listening to Sirius 70s on 7 and watching a fire.

So the Ace system sort of maintains between soaks, but it in no way can handle any bather load.

 

[chem geek]

Well, it's supposed to be able to handle a small to moderate bather load but not a high bather load. You should note that the ACE system can be great when it's working but as noted in this thread on another forum, quite a few people have had problems with their ACE systems. You should check to make sure the cell hasn't scaled up. The ACE system needs Calcium Hardness to be very low -- the system is much more easily scaled than a regular saltwater chlorine generator.

 

[wpbucher]

FC=4 this morning (24 hour after initiating boost when FC=1.5 and nobody in the tub).

Obviously, if someone had been in the tub for only a short time FC would have dropped to zero.

Is there anything special about the "Hot Springs" salt? I've always used 99.9% solar salt after refill. I dissolve the salt in a buck of hot tap water and add it to the spa.

 

[chem geek]

I don't think the salt is any different. Note that I assume you do not also have an ozonator. If you do, then ozone reacts with chlorine and will make it more difficult for the ACE system to maintain an FC level. If they produce say 3 ppm FC (accounting for 0.5 ppm FC loss during 24-hours) over 24-hours then assuming 500 gallons that is only enough to handle around 35 person-minutes of bather load so one person for 30 minutes. That does sound on the low side -- I thought they were able to produce about twice that amount, but I could be wrong.

 

[wpbucher]

I checked that a while ago and determined that the ozonator is not connected. I will double check that once it stops snowing. Maybe I'm too impatient. I don't really understand how the Ace System is supposed to handle bather load. Per the sticky post about chlorine in hot tubs, it takes quite a bit of chlorine for each person/hour in the hot tub. I know that if we have 4 people in the tub for 3 hours, the FC will be zero if I test in the morning. I would freak out and dose with bleach or dichlor. Perhaps I should tolerate FC=0 for a while after a soak. I'm just thinking that if the Ace system produced enough for a 12 hour/person soak, then the FC would elevate extremely quickly once all of the bather waste is oxidized. Then you would have the problem of too much FC in the tub. Hot Springs provides a guide based on usage, but I've never come across that really states how much chlorine the Ace system generates.

If we assume FC consumption of 10ppm FC/person/hour and four people soak for 3 hours then you need 120 FC to oxidize the waste. If the Ace system is generating 5 ppm FC/hour then it will take 24 hours to oxidize the waste. But that could mean that when I test for FC it is zero or .5 ppm for quite a while. After the waste is oxidize the Ace system would continue to generate 5 ppm FC/hour and so in the next 24 hours the FC=120 (less usual loss)....even FC=80 sounds crazy and will eat (oxidize) a lot of vital components in the hot tub. During the 24 hours when the FC=0 to .5....how much stuff is growing in the hot tub? How much more time does the ace system need to catch up to the algae/bacteria growth that results from a low FC level?

I just don't know how the Ace system is supposed to work when bather load is so erratic. No demand for 1, 2, 3, 4 days and then high demands for two days in a row (weekend). FC would have to fluctuate accordingly since the Ace system generates a constant amount of FC during that period of fluctuating bather load.

Maybe I need to just use the tub. Shock to some level (15 ppm?) once a week and stop worrying about the FC levels?

 

[JasonLion]

When the bather load is not uniform you start manually adjusting things to try and compensate. For example the manual says to manually turn on boost in advance of one time heavy usage, while if you are not going to be using the tub for a while they say to turn the level down to one and reduce the spa size setting below the actual spa size.

Spa oxidizer demand varies wildly depending on usage. None of the current generation of systems really take that fully into account. There are some systems that are a little more advanced about it then Ace, but none of them deal with it completely. The best available systems have a counter on boost so you can boost a little or a lot and you are supposed to boost some appropriate amount after each use.

Finally, three people for three hours a week is very heavy usage from the Ace system's point of view. So I wouldn't expect it to be able to generate more than (very approximately) 100 ppm of chlorine a week. The manual even acknowledges this to some extent, recommending manual chlorine additions to supplement during heavy usage when FC levels are not keeping up.

One common adaptation to these issues is to manually add chlorine proportional to usage after each use and to set the Ace system to a low setting to take care of basic chlorine needs that are not proportional to usage. Obviously this is not ideal, but it is very practical and tends to work smoothly.

 

[wpbucher]

Jason: I agree with everything that you stated in your post. Can you overdose the ace system? If you follow the directions on the dichlor/bleach method you are adding a lot of bleach. My wife and I were in the tub last week for 2 hours (4 person hours). I added 12 oz of 8.25% bleach. I ran the jets for 10 minutes with the spa cover off. Before I closed up the spa I took a sample. FC was 16.5 ppm. The following morning (12 hours later) it was 11.5. The following day (24 hours later) it was 7.5....next day 4.5....next day 3.5....next day 3. I increased output from 7 to 8 and the next day FC=4.

So basically, I'm shocking the spa every time I use it. Is this an issue? Or should I be adding less initially and then continue to add bleach for several days afterward without going above some maximum amount of FC?



Also:

I was re-reading my Ace Owner's Manual. Under specifications it states:

The maximum output of hypochlorous acid equivalent to 16 grams of free available chlorine per day

Does this mean the Ace system can produce a maximum of 16 ppm of free chlorine per day?

 

[JasonLion]

Generally you want to add a fairly large amount of chlorine right after each use, and then a much smaller amount at regular intervals. You are dealing with two different effects, bather waste that needs to be oxidized, preferably quickly, and the slow consumption of chlorine from just sitting there even when no one is in the spa. They can't add a lot "all at once" so they add a medium amount constantly for a while. If usage is very consistent that can work out well, but if usage varies then it is easy to get the amount of chlorine added by the system wrong. So, yes it is possible to overdose significantly with the system when usage is on the low end of the range.

16 grams of chlorine (gas) is not the same thing as ppm. You can use the Effects of Adding Chemicals section of PoolMath set to chlorine gas to figure out what that is in ppm for your spa. For a 500 gallon spa it would be 8.5 ppm per day.

 

[wpbucher]

So per the " How do I use Chlorine in my Spa (or pool)?"....

Quote:
the rule of thumb is, you'll use approximately 7 ppm FC per person per hour in a 350 gal tub.

Another Quote.
the 7 ppm FC in 350 gallons per person per hour of soaking guideline (at 104F) isn't in the Pool School either. This translates into amounts that are independent of spa volume of 3-1/2 teaspoons of Dichlor or 5 fluid ounces of 6% bleach or 7 teaspoons of MPS non-chlorine shock. These are conservative amounts of chlorine needed to oxidize bather waste (mostly ammonia/urea from sweat/urine). The biggest mistake most spa users make is not using enough oxidizer in their spas, especially if such spas are more heavily used.

So if the Ace System max output is 8.5 ppm FC per day, then it will be necessary ALWAYS add dichlor/bleach/MPS after a multi-person soak for more than approx 35 minutes.

I guess I only have heavy user load. It ranges from 4 person/hours to 16 person/hours per soak.

Based on the above quotes, I think I might be doing things correctly.

I'm amazed that I've never come across posts from Ace System owners who state they have to add dichlor/bleach/MPS to oxidize user waste AFTER EACH USE while relying on the Ace system to maintain chlorine levels between soaks.

Thanks for your response. I sent an EMAIL to Watkins Mfg describing this issue. I'll let you know if they respond.

 

[JasonLion]

Any way you look at it, your usage sounds like heavy usage.

They do mention that you can tell the system that the spa is larger than it actually is as one approach to getting it to produce more chlorine.

 

[chem geek]

Note that the rule-of-thumb is based on a hot (104ºF) spa. There's no way you are soaking for 2 hours at 104ºF so you probably have the temperature lower and that means you are sweating less and that means you will need less chlorine than the rule-of-thumb. Also, the ACE system is adding some chlorine over the subsequent 24 hours -- just not enough to handle bather load. The real rule is to add whatever amount of chlorine is needed after the soak so that you never get to zero chlorine in between soaks -- usually so that you start your next soak with 1-2 ppm FC (unless you want it higher for more person-to-person protection with strangers).

It seems to me that you're using about double what you need to use given your actual bather load when accounting for temperature and accounting for the ACE doing something even if it's not enough. It sounds like setting your output to 7 or perhaps 6 would have a background chlorine level of 2-3 ppm. Perhaps even 5 for 1-2 ppm FC might be OK. That way the ACE is used for a background level of chlorine in between soaks and the Dichlor-then-bleach method is used after each soak.

 

[wpbucher]

Any way you look at it, your usage sounds like heavy usage.

They do mention that you can tell the system that the spa is larger than it actually is as one approach to getting it to produce more chlorine.

I wish I had a spa size option.

A lot of the Ace Sanitizing System manuals are old. Hot Springs "simplified" the interface by eliminating the "spa size" option from the user interface. Thus, spa size is either set on the board (dip switches, jumpers, or something) or in the software. My guess is that it is set in the software. Did mine get set correctly? How can this be determined?

I included a picture of the software version numbers at start up. I was hoping a Hot Springs tech might be able to decipher the numbers (sort of like a VIN number on an auto) and tell me that my unit has the correct software.

No word from Hot Springs yet.

 

[wpbucher]

My experience has been that in between soaks...once FC drops below 5ppm....a setting of 7 yields a daily loss of about .25 ppm. In other words if FC=4.5...it will be 4 two days later...then 3.5 two days later....then 3 two days later....etc.

At some point, we soak again and the cycle repeats. I'll dial it back to 5 today (FC=2.5) and let you know what it is tomorrow.

My point in all this is that after basically shocking the tub after the soak (using twice as much bleach as necessary) and not using the tub in week, a setting of 7 or even 5 should be causing the FC to rise.....not fall.

Thus my contention that the Ace System is not producing the FC that one would expect. Unless I don't understand the whole "usage scale".

If you add oxidizer to eliminate all waste from the bather load, then isn't it as if the tub had not been used?

This would make sense, because I don't really see a difference in FC when I switch the "ace filter" every three weeks.

This is probably overkill...but this is my filter schedule.

I bought 5 extra tri-x filters (filter set B) to supplement the original 5 tri-x filters that came with the tub (filter set A).
1. After a drain a refill, I install filter set A.
2. Every three weeks:
A: I spray off all the filters with hot water (45 degree angle and all that).
B: I replace the filter with the Ace Cell (Cell filter) with a clean filter from filter set B. The rest of the filters go back in the spa.
3. After 5 iterations of step 2, all of the filters in the tub are from filter set B. I then soak filter set A overnight in TSP or SpaDepot Power Soak...rinse and dry.
4. After 3 weeks, I drain/refill and replace all of the filters in the spa (filter set B) with filter set A.
5. I then soak/rinse/dry filter set B and begin the process over.

NOTE: Depending on usage...and the weather I usually try for a drain/refill every 4 months. I will change the water in early March...hopefully a 50 degree day will show up.

After a heavy usage soak with new water, I don't really see a difference in FC demand between "old" and "new" fill water.

I really "baby" this hot tub. I guess that is why I've had zero issues with it....except my perception that the Ace System is not producing enough FC.

 

[chem geek]

My point in all this is that after basically shocking the tub after the soak (using twice as much bleach as necessary) and not using the tub in week, a setting of 7 or even 5 should be causing the FC to rise.....not fall.

Thus my contention that the Ace System is not producing the FC that one would expect. Unless I don't understand the whole "usage scale".

If you add oxidizer to eliminate all waste from the bather load, then isn't it as if the tub had not been used?

This would make sense, because I don't really see a difference in FC when I switch the "ace filter" every three weeks.

You are correct. It does seem that the ACE is weak on chlorine production. Note that it is designed to produce more hydroxyl radicals so doesn't produce a lot of chlorine the way a saltwater chlorine generator at 2000 ppm salt such as the ControlOMatic Technichlor would.

 

[wpbucher]

I checked this morning. FC had dropped from 2.5 ppm to 1.5 ppm with output=5. So back to output=7.

How fast does chlorine oxidize waste?

Typically, I will check the FC and PH levels about 10 hours after soaking and dosing with bleach.

In a previous post, you mentioned that I used 2x as much bleach as necessary.

Is there a target FC level I should be aiming for 10 hours after a soak&dose?

 

[chem geek]

Most bather waste is oxidized within 24 hours. A lot is done in 12 hours, but there is some that takes longer. It's also temperature dependent.

It's hard to give a target 10 hours after, but if you plan to soak the next day then something like 3 ppm FC might have you in the 1-2 ppm FC range when you start your soak.

 

[SpeedStar]

Most bather waste is oxidized within 24 hours. A lot is done in 12 hours, but there is some that takes longer. It's also temperature dependent.

It's hard to give a target 10 hours after, but if you plan to soak the next day then something like 3 ppm FC might have you in the 1-2 ppm FC range when you start your soak.

I am in this exact scenario with Grandee and ACE SWCG. Trying to figure out what output level to set the ACE at and the then supplement with dichlor / bleach after each use.