Intellichem Prematurely hitting Daily ORP limit

[E&J]

New pool owner, completed in July of last year. My intellichem worked beautifully all last year, but this spring, I started noticing that I was reaching the ORP Limits on a daily occurrence, so I just started upping the limits and dosage, to the point now that I'm at 15 doses of 1/3 gallon (42 oz) per dose, with a mix time of 45 minutes. (Set it at this point so that it would essentially be 5 gallons (more than my container 4 gallons) and I could see if the pump was actually dosing 5 gallons, or if the software just assumed it was dosing that amount. And have deduced that in fact, my stenner pump is NOT putting out that much chemical in the period of one cycle day. At most, I've seen it dispense about a gallon before the ORP limit light comes on, and that light sometimes comes on 2-3 hours after I have manually cleared the limit. (Confusing). The limit is set to naturally clear at Power-On, and the Intellichem does not stay powered on the entire day, it only has power when the pool is in filter mode. (10:00 am to 8:00pm).

Things I've done to correct:
I thought perhaps my filter pressures were too high- the stenner pump is 25PSI, my filter was running about 20, so I thought cleaning my cartridge filter might help. It did lower the PSI to about 14, but that did not clear my issue.

I read where the pump tubes need to be replaced annually, so I change the ORP pump tube. Still reaching the ORP limit.

What's a mystery, is that as long I keep resetting the limit, the intellichem can still keep my pool at my ORP set point (700). Water is beautiful, and my manual checks of the pool all show in range, the Intellichem is actually dosing the pool with Chlorine correctly, but something is triggering the limit.

I've called Pentair support, and they will dispatch technician for warranty (which is the installing company), and the technician has been honest with me, saying that his company has only installed one other Intellichem system, and he says I probably know more about this setup than he does. Just trying to see if someone has some idea of what could be causing this limit to be invoked prematurely. Is this a hardware issue, software issue, or just plain old User Error?

Ph.7.6
Chlorine- 3ppm (OPR of 700)
Total Alkalinity- 65
Calcium Hardness- 300
CYA- 40
21,000 gal
Plaster bottom

 

[Bama Rambler]

Do you have a good test kit? If so, please post a full set of test results from the kit.

Have you calibrated the system lately?
How old is the probe?
What strength bleach are you using?

It looks like your ORP setpoint is still at the default setting. Was that set based on the actual FC or just left as default?

 

[E&J]

Thanks for the reply, Bama Rambler. Water Tests Are:
Chlorine 3.8ppm
pH- 7.6
TA-65
Calcium-310
CYA- <30, but don't know exactly how low. Tests were for today.
added 1 gallon of conditioner last weekend, may need one more.

However, I think I solved my own problem.....and I'm posting in case I'm not the only idiot that got confused.

The dose and limits on the intellichem are both in the same measure (oz/ml). I thought the dose was in oz/ml, but the limit was a multiplier of how many TIMES the dose would be dispensed. Turns out the limit is also in oz/ml..... My dose was set a 15oz, and the limit was set a 42, thinking that my intellichem would does 15 oz, 42 times, or nearly five gallons before the limit would be reached. In actuality, the "42" is also in ounces, so my intellichem could only does twice (15oz dose, times 2 is 30oz), but it cannot dose a third time, because that would be 45 oz, which would exceed the 42 oz limit.

The lesson learned: small doses more frequently is better than large doses infrequently. Also, adjust the limit upwards, and leave the dose alone, if your intellichem is limiting out.

NOW that that is resolved, why is my pool CYA so low, and hence, is that affecting how much chlorine I'm going through? When the pool was started, the pool builder added 1 gallon of conditioner (as far as I am aware, and then I added another gallon later, once I took over the pool. Don't remember the ORP limit being breached last year....
This spring, we had TONS of rain, and I pumped my pool out several times, for 20-30 minutes. I'm thinking a lot of the CYA I had in the pool must have gone out during those times I pumped the pool down. I added one gallon CYA this year, and the black dot is still barely visible even when I do the CYA test and fill the test guauge to the top, so I am presuming my CYA level is below 30.
I don't want to overdue it, so I'm cautious about adding another gallon of CYA. (The full gallon should increase my CYA by 15 PPM (32PPM increase for 10K gallons label) since my pool is approximately 21K gallons.

Is adding another gallon appropriate or do I have another issue I haven't discovered yet?

Jason

 

[Bama Rambler]

It sounds like you need more cya. having to pump off a lot of water will certainly lower your cya a lot. I'd add another gallon and test it again. Well actually I'd use Poolmath to figure what I needed and I'd also use granular instead of liquid. but that's just me.

 

[E&J]

Update, part 2: I am still surprised at the amount of Chlorine I'm using, so I continued investigating..... Last year, when I bought an adequate supply of chlorine, I was assuming my chlorine usage would continue year round..... Not so....

Once the water got cold, the Chlorine behaved well and stuck around, hence, I have about 30 gallons of chlorine that I purchased last year, still in my store room. From reading, I suspect that the chlorine I bought last year has lost a lot of its potency, hence why I am noticing a heavy than normal rate of use, and my intellichem limiting out.....

I am going to buy the 1000ml flask and a syringe to test the PPM chlorine in an unopened bottle, to confirm, but I bet this is my culprit.... Any idea what the decay rate of chlorine is in Texas, 100-110 degree heat, left in the cardboard box and stored inside a dark, non-climate controlled shed? I will also test each batch I purchase and make sure it's not "flat" when I buy it. I just didn't figure bleach would lose it's strength if the bottle hadn't been opened.... Trying to figure out how many gallons to buy each trip, so that I can minimize decay loss while also maximizing convenience. (i.e, can I buy a one month supply, half a month's supply, or 2 months supply at any given time, and buy the time I use the last gallon, still have at least half strength product?)

For certain, I'll report back my findings for others who seem to be vexed about this as well or in the future.