PH Control Advice Needed

[jfpetesn]

We moved and installed a new radiant metric hybrid pool last year. It went very well overall. I discovered that our well water and city fill water has a very high TA (around 460). I fought hard all last year adding gallons of MA to slowly get it down. I was able to get it to around 140 by seasons end. I fairly certain that this is something that I am going to be fighting forever so I am looking at a way to automate my MA administration. I also have SWG.

I have looked at the Hayward and Pentair liquid feed products. I have all Pentair setup with an easytouch control panel, with SWG, intelliflow pump and screen logic controls. The Pentair intellipH (abut $450-$500 would interface with what I have but is just a timed feeder.

I have another idea:

I used and own a Polaris Watermatic automatic chemical control system with ORP and pH controls. I brought it with me from our old pool when we moved and really thought about selling it as it is a very nice setup. I used it to feed bleach and MA in our old pool. The learning curve was very high as I went through the typical CYA level vs ORP issues. Took a good season of experimenting to finally be able to use it effectively. I am not interested in monitoring ORP just pH. In the past, I never had any problems with my pH sensor, it was my ORP sensor that drove me nuts. I had to keep my CYA below 30 to get it to function reliably.

I want your opinions, should I purchase the Pentair intellipH product or should I dismantle my Watermatic system (2 stenner pumps, contrller, etc) and just use the pH portion of the system? It is all mounted on a big board. I just need the one pump, the controller, and a 5-8 gallon container for the MA.

I kind of hate to dismantle this great system but I bet I couldn't get much over $500 for it if I were to sell it. So I already own what I need and know how to operate it but it is more than I need. I think it would be nice to have the pH sensor to control it vs just a timed system.

Please let me know what your thoughts are. I would probably need to purchase a new pH probe and stenner pump tubes but I could use what I have and make it work. I also thought I would wire the watermatic into my easytouch panel so that it only runs when the pump is on.

Thanks
Jeff Peterson

 

[JasonLion]

My favorite setup is a Stenner pump with a timer. Having a sensor just adds complexity and cost to no real purpose. You can probably use one of the aux relays on your EasyTouch as the timer, and a Stenner pump from your Watermatic system and not have to spend anything (or at least very little).

 

[jfpetesn]

So you would forget trying to automate the pH control all together? I do think I can wire one Stenner pump into my easy touch panel. I just need to find a tank. I just thought that since I already have the pH controller I could use it but you are probably correct to keep it simple. I would just have to play around with my dilution and stenner run times to get it right.

 

[dschlic1]

Unfortunately just controlling your pH is not going to help with the TA issue. Every time you add water, you will be raising the TA. So every so often you will have to perform the TA reduction procedure. My fill water has a TA over 200 so I have a similar problem.

 

[JasonLion]

dschlic1, if the rate at which high TA fill water is added to the pool is even remotely uniform, it can be compensated for by automated regular acid additions. Things get more complex if you suddenly have to add a lot of water, say while having a leak, but but really that just means adjusting the feed rate a bit more frequently. If you have PH automation, and the peak acid feed rate is high enough, even wildly non-uniform water additions are taken care of by a PH automation system.

The only significant exception to this is if you also have high CH fill water, and keeping TA low is critical. Then you need to add acid as rapidly as possible directly after adding fill water to get TA back in line as quickly as possible to prevent calcium scaling. Even there an automated acid feed system is a huge help, it just requires very frequent attention to the feed rate for a while after each water addition.

 

[jfpetesn]

Last season I would drop the pH to 6.9-7.0 then aerate to raise it back up. I could not get them below 110 though. I am hoping that this year I will not be starting with a big fill so I am hopeful that with feeding MA at some constant daily amount I will have better control. I looked my Stenner pumps are 50 gpd. I have 21,000 gals so I'll have to figure out where to start. Anyone have any suggestions which relay to put the Stenner on or does it even matter? Thanks for the advice. Now I am going to try to find a 5-10 gal tank or carboy to use. BTW we used little fill water through the season last year. Rains came right. I try to not add well water unless I have to.