Alternate Title: Dichlor – Bleach – Ace

Short Version: I've had the Ace System a little over two years. Through a lot of trial and error, I've found that the Ace System (AS) cannot be used as the sole provider of chlorine to my hot tub. The Ace System simply cannot produce the required amounts of chlorine to handle anything except the lightest of bather loads. It does a great job of maintaining chlorine levels. Thus, it is allows you to “do nothing” to your spa for days (perhaps many days) at a time. NOTE: Not checking your spa chemistry for weeks at a time is not recommended.

Long Version:

Background: I have a 25K pool with a Pentair IC40 SWCG and borates. That set up has worked great. So when it came time for a portable spa, I decided to stick with chlorine rather than bromine.

I assumed the AS system would be similar to my pool. The SWCG in the pool is able to handle bather load. Throughout the summer, I add MA, salt, and borax. I rarely add any bleach to the pool.

From the start, it did not appear that the AS was producing enough chlorine to handle bather load. I then decided to add borates to “help” the AS. This resulted in a “high salt” reading and a partial drain and re-fill. Adding borates did not help chlorine production. I did learn that adding bleach and MPS to the tub also added salt to the tub.

The next time I changed the water, I decided to avoid the high salt situation by adding borates before the salt. I then added salt until I was 33% from the bottom of the good salt range. Based on the AS measuring system, I could add only 2.5 pounds of salt. I limped along with the AS and basically did the dichlor – bleach method. Summer came and I had to have the AS running at 5 all summer. Nobody really used the spa in the summer (we have a spillover at the pool). After 14 months, the AS cell died (black flakes in bottom of spa). After winter, I “winterized the spa in the spring” when I opened the pool and spillover spa.

In late summer I ordered another cell. I figured that I would give AS one more chance. Upon opening the spa, the control board was bad, so that was replaced under warranty.

Over the summer, I came upon a post on the Internet that stated that the AS salt measure wasn't a measure of salt, it was a measure of Total Dissolved Solids (TDS). A little cracked lightbulb went off above my head. I had our well water tested and the water company said everything was fine. The TDS were a bit elevated, but not worth remediation. I bought a TDS measuring stick from Amazon and it showed TDS of 170 in the fill water. This could be partially due to the fact that we have a water softener that uses salt to soften the water. Fill water had CH of between 0 and 10.

It then occurred to me that the MA – 12 Mule Borax must be contributing a lot to the TDS. That is why I could only add 2.5 pounds of salt. The instructions say to add 6 pounds of salt. Perhaps I had been “starving” the AS system of salt and that is why it performed so poorly?

After getting water chemistry right (dichlor to get CYA to 30ppm and ph 7.4), I added 4 pounds of salt. I waited 24 hours and added another pound. This brought the AS salt level to about 33% into the good range.

One light use of the spa and then the wife went on a business trip to China. She then came back and had her ACL replaced (sking accident past March). This meant that the spa had no load. I found that a setting of 2 would result in a loss of .5 ppm of chlorine per day. A setting of 3 resulted in an increase of about .5 ppm per day. With AS turned off, I would lose about 1 ppm per day.

After no use for about 10 days, I decided to crank it up and see how much chlorine the AS could produce. A boost cycle (24 hours) yielded an increase of 6ppm. Given a 1 ppm loss, I figure the ACE system can produce 7 ppm in a 24 hour cycle.

Given that the Dichlor-Bleach method states that up to 7ppm chlorine is required for each hour of bather load, I concluded that the AS cannot produce enough chlorine for two persons in the spa for two hours....or even one hour.

I usually keep the temp around 98-99 degrees. So the chlorine requirement per bather hour is less.

Since my discovery, I simply use the AS as a “when not in use” sanitizing system. I follow the dichlor-bleach method and once the spa has settled down from bather load, I let the AS do the rest.

This past weekend we had four adults in for four hours. Started at 3.5 ppm and I'm sure went to zero at some point. When we were finished I immediately added 20 oz of bleach. Next morning (12 hours), there was 8 ppm in the spa. At 24 hours, there was 4.5 in the spa. The next day 2.5. The next day 3.0. When the chlorine rose, I knew the AS was in handling the situation. If the chlorine dropped below 2.5 ppm, I would have added bleach.

1. The Ace Sanitizing System requires dichlor and bleach.
2. Borates do not seem to be compatible with the AS due to the increase in TDS. With borates you cannot add anything close to the amount of salt recommended in the instructions.

Everything is going great with the spa. Hopefully, this cell will last longer than 14 months.

At the moment, I'm very close to “high salt”. From the bottom of the good range, I would say I'm at 98%...or 2% from high salt. I used the TDS stick and it read 2240 ppm. Is there any way to reduce TDS other than partial drain – refill? Will the Vanishing Act calcium remover reduce TDS?

This post is to added to the body of knowledge that is TFP.