new guy, new pool, SWCG + acid induction questions

Apr 5, 2010
3
Hi guys! I'm new here (and to pools in general), but I just wanted to say thanks straight away for all of the very valuable information that you all have provided to me already. I've been lurking on the forum for a couple weeks now just reading and gathering information. I have a couple specific questions about my situation that I hope you will have some input for.

My wife and I are in the process of trying to put an in-ground diving pool (no spa) in our backyard in AZ. It looks like it will be roughly 21,000 gallons when we're done. We're working with 2 different designers currently and are hoping to settle on one soon to get started. I mentioned salt systems to both of the designers and both of them reacted very negatively. One recommended the Frog mineral pack/chlorinator instead and the other recommended just adding chemicals manually as needed. I was kind of surprised about that given how much people here seem to like their saltwater systems. One of the designers went as far as saying that he was going to start making his customers who insist on salt to start signing an "I told you so" waiver. Are these just scare tactics driven by profit motive or should I really be listening? The more I read here, the more I question their motives.

The cons that they mentioned (to the best of my recollection) were the following:
1) We are on ground table water, which is generally very hard water and contains high levels of calcium according to them. They were saying that scaling is going to be a huge problem and we'll be destroying cells in no time. While I buy the high mineral content argument, reading here it seems like scaling is only a problem if you let your pH get out of whack.
2) Splash out onto flagstone erodes the decking. I'm not sure that we'll be going with flagstone either way, but this seems like it could be a valid concern. If it is, then what decking materials would be more resistant to the salt system? I like exposed aggregate concrete, but it may be too hot on the feet to be useful here where summertime temps are generally north of 100 degrees everyday and the sun is very intense.
3) The cells will have to be cleaned with acid and replaced constantly. From reading here, this seems like a false statement if pH is kept in check and you buy a generator that is oversized for the pool so that you don't have to run it at max capacity all the time.
4) You have to add a lot more acid. This does seem to be the case, however, the automatic feeder systems here seem to be a good way to reduce the burden.
5) You have to check pH more often and really stay on top of it. This also seems to be the case, however, it seems like with some of the newer systems this can also be mitigated. I plan to test the pool every week anyway, so I don't see the time factor being a big consideration unless once a week is not enough for salt.

One of the designers actually went as far as saying that they still make plenty of money on SWCGs, indicating that his motives weren't profit driven, however he said something like they'll charge $1400 for a SWCG that only costs them $400. That makes me wonder if they're just using some of the crappiest available generators, which is part of the reason they have not had good experiences with them. If we go the salt route, I was thinking of using the Hayward AquaRite Pro system with sense and dispense driving a peristaltic pump to induce acid for pH control. I would not use the ORP sensing after reading the input of several board members here. Given the location of the pool (direct sun) and intensity of the sun here, it sounds like I'll need to keep stabilizer levels at a ppm that would be too high for ORP sensing to be effective anyway. It seems like this system (rated for pools up to 40k gals) would be large enough to not strain it even in the summers here and would give me a good automatic pH leveler system all for around $2000. I looked at the AutoPilot/PoolPilot products as well, but it seemed that to get exactly what I wanted out of the system it was going to run closer to $4000. What do you guys think? Any personal experiences you'd like to share with this type of setup would be awesome. I read mas's thread about the homemade acid induction system extensively. That system looks great for a homemade/DIY thing, but in this case since everything is going in fresh, I think I'd rather just drop the $200 on a pump and have it controlled by the sense and dispense thing if possible.

My current thinking is that I will probably purchase my own SWCG system and either have them install it or just leave space in the plumbing for it and I will install it later. Are there any pitfalls with this arrangement that I should be aware of (like plumbing lengths, sizes, etc .. things that would make compatibility for adding a SWCG later difficult)? Also, is there any reason that the pH only sense and dispense system wouldn't work well with solar heating? I can't think of why it wouldn't, but I recall reading that when the solar is active, it changes the flow rates and/or run time of the pump or something. We're probably not going to shell out the cash for solar heating when we build the pool, but we'll plumb the stub connections for it and size the pump and things to accommodate one should we decide to add one in the future.

- Scott
 
1) High CH levels can be managed to avoid problems, but you do need to have some idea of what you are doing. Mostly you keep the PH and TA levels fairly low.
2) There can indeed be problems with some kinds of natural stone, including flagstone. If you avoid those kinds of stone, everything should be fine. Concrete is safe with a SWG.
3) The cell will almost never need to be cleaned if you keep your levels balanced.
4 & 5) If you balance your levels properly, you won't have any problems with the PH. If you let your TA get too high, PH can rise very rapidly and cause trouble. The key is knowing what you are doing. Then you can avoid problems before they start.

I expect they are being honest with you, given their limited knowledge of what is really going on and how to avoid it. Many people who don't have the first clue about how to balance their levels simply assume the SWG will take care of everything for them and let things go. That can indeed lead to problems. But if you do a little reading at Pool School, especially the article on balancing your levels for use with a SWG, there won't be any problems.
 
Thanks for the input Jason!

It looks like I was actually incorrect for the costs of equivalent systems between the PoolPilot and AquaRite setups. They're actually a lot closer than I first realized. It looks like the AutoPilot Total Control with pH sensing and acid injection including a 15 gal Stenner tank and pump would actually only run about $2700 versus around $1600 + tank and pump cost (~$800 for the same stenner model noted above = $2400) for the AquaRite Pro with sense and dispense. Sorry for the misinformation I posted earlier. I suppose a cheaper tank and pump setup could be made/used with either model, but the stenner integrated solution does look really nice for the extra few hundred bucks.

Has anyone been using either of these systems with acid induction for a while and care to comment on their user experience?
 
I have an AutoPilot Total Control system and I love it. I gave up on the ORP control, but that really didn't make any difference for my outdoor residential pool. The automatic acid feed was a life saver and very reliable the first two years. After that, I never even bothered to turn it on because I finally got all my levels just where I wanted them and the PH has been rock steady ever since.

One issue to keep in mind: the PH and ORP sensors need to be replaced every other year, and some of the small tubing that feeds the acid and the sensors also needs to be replaced every two or three years. So the ongoing expenses are a little higher than they might appear, but not a big deal.
 
yes...that is very possible. Once you find a TA # that suits your specific pool...PH drift becomes very minimal. Last two months of the 2009 season, I used about a cup of acid...TA of 70....kids splashing every day and swg on 2-3 hrs a day = PH of 7.4-7.6 over that 2 month period.
 
That's right, my PH didn't change measurably for months at a time. We can tell you how to adjust your levels so your PH is stable. If you are interested, you should start your own topic in the Testing and Balancing section and post a complete set of water test results.
 
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