Significant amounts of Alkalinity Up Required - Any way to reduce?

[ScottPool]

I have a 10,000 gallon pool and find to keep pool alkalinity at right level, I need to add ~25lbs of Alkalinity Up every 2 weeks or so during the swim season in Northern CA. Is that normal. I I also should add about 25lbs of Hardness increaser.....our city water is soft. I elect not to do that and live with softer water....but I think it's important to have alkalinity at right level. Any help to keep costs down would be appreciated.

 

Thx

 

Scott

[RDspaguy]

Are you using tricolor tablets? Switch to liquid chlorine, or cal-hypo (calcium hypochlorite) until your ch goes up then switch to liquid. Though you will still have ph/alk drop from the cal-hypo.

Tablets also raise cya (stabilizer) so keep an eye on that. Overstabilization requires increased levels of fc for effective sanitation.

@waterbearcan explain it best.

[waterbear]

First, what is the surface of your pool? If it is plaster then maintaining the proper calcium saturation index is important to protect the pool surface. If it is vinyl or fiberglass then it's not an issue however, there is some empirical evidence that maintaining a CH of 200 to 400 ppm in a fiberglass pool can lessen both cobalt spotting and iron staining of the gelcoat. Calcium, once adjusted, stays constant for a long period of time. It is only lost by water loss from splashout or filter backwashing if you have a sand or DE filter and replacing the missing water with softened water. I suspect the 25 lbs needed is a one time adjustment. You should not need that much every 2 weeks. It's more likely you need that much to get the water balanced and it will then last you through the swim season with perhaps a small bump up every month or so to maintain the level. 25lbs of calcium chloride anhydrous will raise your Calcium hardness by about 270 ppm while the dihydrate form will raise it to about 200 ppm

Second, how are you determining that you need to add these chemicals every two week? Is this based on pool store testing and a printout? Please post a set of actual test numbers and how they were obtained (dealer or home testing, liquid reagents, strips, or disc, Machine read of not) so we get a better idea of what is going on in your pool. I am going to make an educated guess based on the limited information you provided that you are using trichlor tabs in either a feeder or floater and if you are then RDspaguy's advice is excellent! My advice is to invest in a Taylor K-2006 (NOT the Taylor K-2005) test kit and do your own testing. In the long run it will save you a lot of money, especially if you are depending on pool store software that is programmed to sell you as many chemicals as it can. This is how pool stores make money. Strips are basically useless and meter based kits use inexpensive meters and testing reagents that have limitations because the tests are all colormetric. The Taylor kit uses titrations (counting drops of reagent)

Not sure if you are aware that alkalinity increaser is nothing more than plain baking soda, which can be purchased at a MUCH lower price at the grocery store. The pool specific brand ingredients will say either sodium bicarbonate or sodium hydrogen carbonate, both of which are chemical names for baking soda. Fun fact, the second largest manufacturer of sodium bicarbonate is Church and Dwight (Belgium based Solvoy is the largest worldwide) and all these pool spa companies repackage it and sell it at a high price. You might recognize one of Church and Dwight's main brands, Arm & Hammer. In fact, they sell baking soda packaged for the pool/spa market under the name Arm & Hammer Alkalinity First. However, Baking soda is baking soda so just check the price in the baking aisle of the local grocery.

Once again, please post a full set of test results and we can take it from there.