pH, perhaps ORP automation, new pool, recommend controller?

[bcatv]

I will soon have a new 50K gal plaster pool, and although I will start out feeding chlorine/acid manually, I would like to automate sanitation / pH as much as reasonable. I don't currently plan to use SWG, and have been looking at the peristaltic feed setups. Although I would prefer to automate both ORP and pH, discussion here leads me to believe that ORP automation will require use of significantly more total chlorine due to need to keep CYA below 50, so I am looking at pH first, and perhaps only. I have read the various pump threads, and it seems that the pumps themselves are similar and reasonably reliable, with preventive maintenance. However, I have not seen much discussion of the various controllers. Which brands/models have people had good experience with? (realize this is more typically a commercial item, although not sure why; the Rola-Chem ORP/pH package is ~$1700, which is less than two IC-40 setups running open-loop).
Appreciate any input,
Bcatv

 

[JasonLion]

Very few PH/ORP automation systems are designed for the residential market (AutoPilot Total Control and Hayward Sense and Dispense). Almost all of them are designed for large public pools, and priced for that market. All of the residential systems currently on the market use SWGs, so you are left with only commercial, and thus more expensive, options. Though a few of them call themselves residential, they are simply relabeled commercial systems, and priced in the commercial range.

The CAT 1000 (PH only) and CAT 2000 (PH and ORP) are good models in the relabeled for residential but actually commercial products category. And of course you have already found the Rola-Chem models.

If there is any chance you will consider a SWG, the PH automation version of the AutoPilot Total Control system is also worth looking at.

 

[Guest]

There may not be pool specific peristaltic(sp?) pumps, but doing a google search yielded many chemical pumps.

I personally don't want the SWG systems because of the salt being added to the water. I want to not worry about the splashing water killing plants in the area or the corrosion of the pool. As well, when I drain the water or backwash the salt will not be added to the soil, which will accumulate over time.

Added comment:

I found this link to a pump, $84 dollars. availble at 45, 180 or 360 ml/min rate.
http://www.jmepumps.com/Gorman-Rupp-AMT ... 01090.aspx

 

[dschlic1]

One way to automate pH is to use a pH meter that has alarm contacts. Connect a chemical feed pump to one of the alarm contacts, and set the alarm to turn on the feed pump. On eBay you can find pH meters with alarms for under $300. A chemical feed pump is about $200.

 

[JasonLion]

One way to automate pH is to use a pH meter that has alarm contacts. Connect a chemical feed pump to one of the alarm contacts, and set the alarm to turn on the feed pump. On eBay you can find pH meters with alarms for under $300. A chemical feed pump is about $200.

That isn't likely to result in a system that works dependably for months, and hopefully years, at a time. Pool automation systems use special probes that are designed for continuous use without frequent calibration, relays that are rated for the load they will be handling, test cells to insure proper water flow over the sensor, solid mounting systems, and either waterproof or water resistant enclosures.

Some of the pumps on eBay are fairly good, but I haven't ever seen a suitable PH meter there.

 

[bcatv]

Thanks guys. Any features/reasons that one brand/model stands out among Rola-Chem, CAT, Autopilot, others? Do any of the ORP controllers allow for different mV goals to be used at different times of day? With the controller in the loop, is it possible to manually override and cause more chlorine to be injected?

Also, is the reason that ORP has trouble with CYA 70-80 the slow reaction of FC to additional chlorine injection, or does the ORP sensor just have difficulty getting a good reading in the presence of that much CYA?

 

[JasonLion]

To get time of day programming you need to move up into a much more expensive price class. The way they approach manual over-rides vary. There is always some way to do it, but the convenience varies. You can always turn up the ORP target level temporarily.

Higher CYA levels reduce the effect the FC level has on the ORP reading. Eventually, the change in ORP reading from increasing the FC level becomes smaller than the noise level inherent in ORP systems. For most ORP systems, that happens at a CYA level just above 50. At CYA levels above 50, the ORP reading depends on other, effectively random, things and is useless for controlling the chlorine level. For reliable operation, even a CYA level of 50 is a little questionable, so you really need to keep the CYA level below 50.

 

[Aquaman95]

I'd reconsider the integrated salt system. You'll be adding salt anyway when you add bleach and other pool chemicals. It will take a while to reach the level of a salt system but it will get there. I wouldn't worry about the low levels of salt and I think you'll really enjoy the convenience.

BTW, I have no ties with any salt company.

I'm not a fan of the Rola-Chem pumps. For the price they're not in the same class as a Stenner or even a Blue-White. Stick with one of those two for the money...Stenner should be your first choice.

Regarding the controller, all you have mentioned are very similar. I would pick the one where you are likely to get the best support. For my money I would pick the Autopilot Total Control, although I don't know what the future of that system is now that Hayward owns CAT.

Regardless, I'm sure Autopilot would support it and PoolSean on this board is a great resource. That's another reason to go in that direction; residential users getting good support from the controller companies has always been dicey at best (they're structured to support commercial users, have 8-5 hours, etc.) and now that most have been bought out by the major manufacturers it's gotten even worse since a lot of knowledge seems to get lost in the transition. I've seen it happen with Watermatic, Acu-Trol, Stranco, and I'd bet it happens with CAT.