Is there any automated way to feed cal hypo to my pool?

del

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Bronze Supporter
Apr 3, 2013
44
San Diego, Ca
I just drained and refilled my pool after doing an ascoric (and citric) acid treatment to help remove some metal stains. Some stains remain, but things are much better, and today, the water itself appears to be very clear. I added a sequestrant at the start of refilling and then kept adding a bit more as I continued to fill. I still have my Culator in the strainer basket of the pump just in case. One bit of insight I revceived from those looking at my pool pictures is that I have a lot metal sources by and even in my pool, including flagstone and other stones acually built into the plaster. So, one bit of advice is for me to retire my SWG and to not use liquid chlorine in an attempt to not add too much salt to the pool. So, that leaves me with cal hypo. Yes, I know that by hook or crook I will likely get some salt, but I want to keep it to a minimum. I have never seen pucks of Cal Hypo, so that leaves powder/granuales. I am trying to figure out a good dispensing system for the granules. So far, the bestl (cost considered) thing that I could find is a Koi food dispenser, which might work but will probably get torn up quickly by the chlorine. So, is there such as thing as a residential cal hypo powder dispenser? Thanks.

Del
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
16,098
Tucson, AZ
Del,

I don’t know who you’ve been getting advice from metal staining on but it’s flat-out wrong. Your pebble finish is most definitely NOT a source of metal (or else no finishing company in the world would install pebble surfaces) and flagstone is not a source of metals either. Your stains could be metallic in nature but they can also be “dirty” calcium deposits as well (calcium scale is rarely ever white). Also, things that look like stains are sometimes just etch/eroded plaster. And salt has nothing to do with staining at the levels one uses in an SWG pool.

Bottom line is there is no good reason to switch to cal-hypo as it is only going to make potential metal staining MORE LIKELY not less. It is also going to add 6ppm CH for every 10ppm FC added. Where you live, that’s a recipe for disaster as you CH will skyrocket every season.

Properly balanced water will not cause metal staining and the previous stains were caused by carelessness, not your SWG, not salt, not bleach and not pebbles. Before you go down the rabbit hole of looking into cal-hypo feeders, I think you need to re-evaluate why you think you need cal-hypo.
 

del

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Bronze Supporter
Apr 3, 2013
44
San Diego, Ca
Matt, Thanks for the input. I don't like to name names, but one person was from the industry with lots of experience. This person said that flagstone contained metals. My Google Home assistent said that it was, in part, held together by iron oxide. The flagstone and other stones are built into the plaster. I have cute sones turtles! I never meant to suggest that the pebble finish has anything to do with the metals. So, please excuse me if I created that impression. When I look at the stone built into the pebble finish in my beach entry, I can actually see more staining at the interface of the stone and the plaster/pebble finish.

So, do you think that I should just add the salt and use my still functioning SWG? Currently, with the new water, my pool balance is great. Using my SWG would be much easier for me as it is in fine shape.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
11,636
Northern NJ
Use your SWG. What model SWG do you have? Your signature does not say.

Care to share your water chemistry? Maybe we can help you tune things up. What test kit do you use?
 

del

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Bronze Supporter
Apr 3, 2013
44
San Diego, Ca
AJW, Thanks for the offer to advise. I updated my signature to show that I have a Goldline/Hayward SWG with a T15 type cell (generic replacement). I just finished filling the pool this morning, so the chemistry may be in a state of flux. Here are the results I just took to answer your question. I was not able to dispose of all of the old residual water that was still in the overflow tank for the vanishing edge pump system, so this is a possilbe source for the sodium chloride that is still in the pool. It may also have other unknowns from my old water, such as citric and/or ascorbic acid (maybe). I really do not know exactly how many gallons were left in the overflow tank.

Cl 0 Combinded Cl 0
ph 7.2
Alk 110
CH 140
CYA - test shows less than 30 ppm. I added 20 ppm today - calculated amount
Sodium Chloride is over 200 ppm and less than 400 ppm
Total Dissolved Solids 438
Copper - not detectable - less than .08 ppm

Test Kits used:

Taiylor kit with Leslies label. Taylor 5136 and Leslies 81-330 were numbers on the kit
Copper kit - Lamotte 2619
Sodium Chloride Taylor 5031
TDS - TDS Easy pen H&M Digital (from China)

I do not have a test kit for the (presumably) HEDP that I added when I refilled the pool. I really want to purchase such a test kit soon.

I did add enough cal hypo that I should have had a chlorine reading, but I had none. I wonder if some of the residual ascorbic acid ended up neautralizing the chlorine. Maybe. It could have just been the sun today without the CYA in the pool. The water is currently crystal clear.

Thank you and I would like to read what you suggest.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
11,636
Northern NJ
The Leslies 81-330 kit lacks the FAS/DPD test to accurately test your FC. You can buy FAS/DPD Chlorine & CC's test

I could not find any information on a Taylor 5031 test kit. We recommend the K-1766 Taylor Salt Test

I think you should get liquid chlorine to get your CL up and use PoolMath to determine dosage and if you are getting the expected effect.

You do need to get your CH up into the 250-350 range for a plaster pool. But first thing I would focus on is getting your water to hold CL.

Are you familiar with TFPC methods? I suggest you review ABCs of Pool Water Chemistry and Trouble Free Pool School and the eBook.
 

del

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Bronze Supporter
Apr 3, 2013
44
San Diego, Ca
Thanks again. Yes, I am familiar with these methods. My salt test looks identical to the K-1766 shown in the link. I will purchase the chlorine test that you suggest. I hope my free chlorine goes up soon. Do ypu know of a good hedp test kit?
 

del

Gold Supporter
Bronze Supporter
Apr 3, 2013
44
San Diego, Ca
I added two bottles of sequestrant when I was refilling to prevent metal staining. I had/have what I believed to be copper and iron issues which is why I drained and refilled. I would like to monitor the dehp to make sure that I maintain some minimum level of it without over doing it..
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
16,098
Tucson, AZ
I put very little stock in what industry types think. Many claim way more "authority" than they are entitled to...

OK, I understand the situation you have. There was a similar issue many years ago with the fad of adding crushed abalone shell to plaster mixes to give the plaster a "sparkle". It was all well and good intention until people started seeing little brown rings appear in their plaster surface. Installers were just using crushed abalone that was not properly sourced for pools and the organic impurities in the shells was starting to leach into the plaster and turn brown from chlorine/UV exposure. Once the problem was realized, plaster manufacturers finally started to spec and supply pool-grade abalone shell that was treated to remove or reduce the impurity content.

Likewise, your installer should have known better to be careful with inlaid stone work, especially submerged flagstone. It should have been treated and sealed prior to installation to avoid leeching. Flagstone is nothing more than silica particles that are bound together in a calcium carbonate (calcite) matrix. There can be trace iron impurities that give FS it's various coloration but they are typically bound up in the binder and not subject to loss. If the pool water is very aggressive, it can etch the flagstone and leech out those "impurities". Flagstone is a very poor choice for submerged applications or even for surfaces that are exposed to running water (because of mechanical erosion).

That said, the FS is not a source of iron in the water. That really only comes in from external sources such as fill water or the use of metal containing chemicals (such as copper based algaecides). Iron can be found in municipal water supplies but not necessarily reported because the EPA does not classify iron as a contaminant that needs to be controlled. SO even if you think your city water is low in iron, it may or may not be.

Given all that, there is really no reason to stop using your SWG. In fact, your SWG is probably the least likely method of chlorination to cause staining. Using cal-hypo can quickly increase pool water pH, especially since it typically added as a granular powder and it takes time for the powder to dissolve. Therefore, you can get locally high pH conditions around the powder.

If you keep the CSI of your pool water balanced to slightly negative (-0.3 to 0), then your SWG should operate efficiently and your flagstone should be ok.
 
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del

Gold Supporter
Bronze Supporter
Apr 3, 2013
44
San Diego, Ca
Matt,

Thanks so much for this advice. I reviewed my old pool construcion receipts and there is reference to Gemstone as the pool finish. I am not certain that it was, in fact used, but it looks a whole lot like what is shown on the internet as the Caymen Bay w/abalone finish. Of course, I don't know if that was exactly what was used back in 2005, but it may have been. I need to think a bit more about this, but I likely will put the salt back in the pool. I thought that you might like to see that stones I am referring to. I still like the stone turtle the most!20190127_132739.jpg20190127_132803.jpg

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