High Hardness in a saline pool

susanaes · Postby **susanaes** » Sat 28 May, 2011 01:18

I have a 9700 gl saline pool in FL and a friend of mine is taking care of it because I'm away for a few months.
He had the water tested at Pinch a Penny and they told him the hardness was high 500ppm and recommended a product named Salinity Stain Control. If been reading your forums and I saw that you can soften the hardness by lowering the PH to 7.0 this will require more acid in the pool since my readings are usually 7.5-7.8
should I have him do this or should I tell him to go ahead and buy the product. I hate to start adding chemicals. I've usually done well by just adding acid and salt if needed. He also said that the pool looks clear and there is no scaling.
Any suggestions or any other way to lower the hardness?
Susana

Postby **chem geek** » Sat 28 May, 2011 22:48

I'm not sure where you read about lowering hardness by lowering pH -- that is not true. I think you are confusing the procedure for lowering TA which has one lower the pH to 7.0 and aerate and add acid when the pH goes up (i.e. the procedure described in this post, but that does not affect the CH level.

You can lower your TA and target a lower pH to keep the saturation index closer to 0 so maybe that is what you were thinking of. Note that a saltwater chlorine generator pool has a lower saturation index due to the higher salt anyway. I strongly suggest you get your own good test kit -- either the Taylor K-2006 or the TFTestkits TF-100 -- so that you can know what is in your water. You can then use The Pool Calculator to calculate the saturation index as well as calculating dosages.

As for lowering the CH, that is only done through dilution (partial drain and refill) with water that is lower in CH. There are also Reverse Osmosis treatments in some areas that will lower CH and everything else in the water (including salt so not the best option for you unless you do this before adding salt to your pool). I really don't think your CH is too high to manage if you keep the TA lower. Note that for SWG pools you can also use 50 ppm Borates that will help prevent scaling in the salt cell. In fact, you should read Water Balance for SWGs.

susanaes · Postby **susanaes** » Tue 07 Jun, 2011 22:39

Thank you for your response. The pool is in St. Augustine FL and I'm presently not there and have a friend who has taken care of the pool in the past keep an eye on it. I forwarded him the information you sent me and he is going to keep an eye on the PH, and maybe add borates.He told me there is n o scaling in the pool and luckily I had cleaned the cell before I left so it should not have any either.

white.nelson · Postby **white.nelson** » Tue 10 Jul, 2012 01:20

General water hardness is related to the dissolved minerals in the water. General hardness is a misleading term that is often confused with carbonate hardness or temporary hardness, which is actually related to alkalinity and relates to the "buffering capacity" of the water (its ability to resist pH changes). This means that if the carbonate hardness is high then the pH will be extremely stable or alternatively if the carbonate hardness is low the pH of the water will be able to fluctuate easily.

above ground pool liners

Postby **czechmate** » Tue 10 Jul, 2012 07:22

Lowering PH may be the solution in effort to curb adverse effect of high CH and its potential danger to plaster surface. PH along with the CYA, TA, borates, salt and water temperature is an ingredient to prevent damage if draining is not desirable at the moment.
This moment is at work for last 2 years in my own pool, with CH of 560 and CYA of 90.
I control the otherwise exposed pool temperature with 18x 18 solar sail and balance CSI to close to neutral.
Sure, FC has to be accordingly high. I keep it around 6-7, barely enough, but on a nice clean DiamondBrite with Polaris scrubing daily, algae cannot establish.
One can juggle a lot, but know-how and consistency is a must.