Hypo Cal use and Baking Soda

[Bpotter]

I found this quote on the Pool Solutions website in the tips section:


(Adding calcium increaser (calcium chloride) and alkalinity increaser (sodium bicarbonate) is a recipe for a BIG mess: an extremely milky looking pool that is slow to clean up.)

Last year was the first summer with our pool and long story short the learning curve for care led me to a situation of very low Calcium in the pool. I wanted to bring the levels up to the high normal range so I bought a bucket of Hypo Cal granules. I am using this to chlorinate my pool for now and it seems to be working very well.
I have very good numbers for now and I do have the TF-100 test kit.

I am using the BBB method with the temporary exception of the Hypo cal and this quote made me wonder.

I know that Calcium Chloride and Hypo Cal aren’t exactly the same thing but I’m not sure.

If I ad Baking Soda will I have problems?

What makes the milky mess and why is it slow to clean up?

 

[JasonLion]

If your calcium saturation index (CSI) is positive and you are using cal-hypo you can get calcium clouding. The higher the index the more likely this is. Adding baking soda raises the CSI quite high at the point where the baking soda is added for a little while till the water is throughly mixed. As long as you have several hours with the pump running between chemical additions and you CSI remains reasonable you shouldn't have a problem. If you do have a problem with calcium clouding it can usually be cleared up with a little acid.

 

[chem geek]

In my own pool which has a CSI a little less than zero (around -0.2 to -0.1), I have found that if I add pH Up (sodium carbonate) too quickly, then it would not only be cloudy in the area where I added the product, but it would also form solid calcium carbonate "chunks" that settled to the bottom and very slowly dissolved if I brushed it. The combination of higher pH and increased TA from that product in the region where I added it causes this. I don't use this product anymore since I switched from Trichlor tabs/pucks to using chlorinating liquid.

Richard

 

[Bpotter]

Is that the same as the Langelier saturation index?

I have never calculated my CSI and would assume that a home pool owner that maintains the water chemistry would be in proper range????

Does any one have the conversion chart and the formula to make this calculation?

I am very curious now and would like to check the CSI?

Do y’all see a glairing down side to my method of raising calcium and sanitizing?

I know it’s sort of lazy but just throwing in some granules every couple of days is easy.

BTW I am always amazed at the depth of knowledge on this site. Thank you so much for the answers.

While I’m going on like a school girl with a crush I’ll say that getting the test kit was really the best thing.

I did resist at first but now it’s obvious and it has taken me a long time to realize how much trouble the pool store was causing.

Case in point is that my water was leaching the calcium out of pool surface and the test they used didn’t show dangerously low calcium levels.

 

[duraleigh]

I have never calculated my CSI and would assume that a home pool owner that maintains the water chemistry would be in proper range????

Bpotter, I am in agreement with that statement (I think ). I have never used it and am not sure it is an essential measure of most residential pools. I believe the simpler we keep our measurements the more people will be able to understand and maintain their own pools.

If I'm off base on CSI and it is essential, I am open to incorporating it into our general discussions here but, in my uneducated opinion, it seems mostly redundant and a measurement that can add difficulty to the average pool owner trying to still grasp the very basics of pool water chemistry............which is the description of the average poster who comes here looking for help. :lol:

 

[JasonLion]

The CSI is very much like the LSI but more precise. You can calculate it by going to The Pool Calculator, see the link in my signature, and entering all of your test numbers and the water temperature. It will then show the CSI in green CSI row towards the bottom.

The usual recommendations for the various numbers tend to result in more or less balanced water and there is a fairly wide range of CSI values that you can be at without any problems so things normally work out. However, with a plaster pool it is a good ideal to check the CSI every once in a while, particularly when any of your numbers are at the extremes of the normal ranges or beyond them.

 

[duraleigh]

it is a good ideal to check the CSI every once in a while, particularly when any of your numbers are at the extremes of the normal ranges or beyond them.

Jason, that makes perfect sense to me and is an enlightening post. So, as long as our parameters of are within the ranges we usually recommend here, it follows that the CSI will also be at a safe level (-.6 to +.6......I think). Is that correct?

 

[JasonLion]

So, as long as our parameters of are within the ranges we usually recommend here, it follows that the CSI will also be at a safe level (-.6 to +.6......I think). Is that correct?

That is essentially true.

However, there can be some rare exceptions. If all of your numbers are at the worst extremes of their range there can be issues. For example, PH 7.2 TA 60 CH 200 CYA 80 Borates 50 Salt 4500 Temp 70 gives you a CSI of -1.15. All of those individual numbers are reasonable, but taken together they can cause problems. Getting into such a situation seems very unlikely, but I like to check the CSI just to be sure. Since my Pool Calculator makes checking the CSI so simple there isn't any reason not to do it.

For completeness, I should point out that both LSI and CSI are slightly controversial. The indexes indicate the potential for plaster damage but not the rate at which it will happen. There are cases where CSI will indicate problems but no problems actually occur because the rate is so slow that you would need to wait years to see anything happening. There are also situations, like the inside of a SWG cell, where water with nominally reasonable CSI numbers can still cause problems because of the unique chemistry happening inside the cell. Despite the exceptions, following the CSI will give you better results on average than simply ignoring the entire issue.

The CSI is particularly good at predicting calcium clouding. Most of the exceptions relate to scaling.