Must reduce calcium hardness

[goodgnus]

My CH is 2500ppm after 3 years of evaporation in AZ and after using calcium hypochlorite for the majority of my chlorination. The rest of my levels are proper, it's the CH that's throwing off my saturation index massively. It's also causing scaling. I need to get the stuff OUT!

I've done some reading on the internet and have noticed that using trisodium phosphate (TSP) is ill advised due to the amount of phosphates introduced. I do see a product on the internet called Calcium Hardness Reducer. Also something called Super Sequa-Sol (a sequestering agent).

Does anyone know which is more effective at removing calcium? I have no problem dumping a few bottles of phosphate remover in after the CH has been reduced. I do not have the time to drain and refill the pool and am concerned with my plaster cracking if it dries out as the temps here are reaching 100. Spending money on calcium reducer and phosphate remover is more cost effective as it's less timely for me.

Thanks for your input.

 

[goodgnus]

Is it true that sodium carbonate will force calcium carbonate to precipitate out and allow it to be vacuumed out?

I'm also seeing something called sodium hexametaphosphate which is said to reduce calcium hardness.

 

[engteach43]

Goodgnus,
I live in Mesa. I checked into the calcium removal companies and was very unhappy with how much they charge. I do a drain every two years. I make sure to do it before the middle of March and have had no trouble with cracking (I have peppletec). I can get it done in a weekend and I have a very slow sump pump. When it's draining I also do a thorough cleaning of the water line on the tiles. The total cost was an extra $40 on the water bill for one month and that was it. If it is in any way possible to do a drain, or even a half drain, I'd recommend that over the calcium elimination services.

 

[CaOCl2]

Is it true that sodium carbonate will force calcium carbonate to precipitate out and allow it to be vacuumed out?

I dropped my CH from 150 ppm to 20 ppm . . . in a beaker. Over in Europe that's how they're doing it, depending on the TA they'll either use sodium carbonate (if the TA is relatively low), calcium hydroxide (if it's relatively high). They also have some commercial products based on oxalic acid.

They also use floc to accelerate the process of clearing up the water, vacuuming the deposits to waste.

So the method it to fill up the pool over the skimmers, put the filter on recirculate, add the pH+, turn off the filter after about an hour, add the floc, let the deposit settle (a few days) and vacuum carefully to waste, then rebalance the water.

But yes, I took a 1000 mL beaker filled with 150 CH pool water, added sodium carbonate until it became cloudy, let the thing settle overnight, then tested the (clear) water on the surface . . . 20 ppm.

 

[JasonLion]

I recommend replacing most of your water. That will get the CH level down reliably and predictably in a relatively short period of time.

 

[chem geek]

The problem with the sodium carbonate (pH Up or Arm & Hammer Super Washing Soda) method is that you can't control where the scale will occur. If you are lucky, it will mostly cloud the water and the flocculant will have it settle where you can vacuum to waste. If you are unlucky, then scale will form on the pool walls or elsewhere. This is why dilution (water replacement) is safer.

 

[goodgnus]

I need to test our groundwater again, but if I remember correctly when I filled 3 years ago it was 800ppm. This is common in the desert.

I may just bite the bullet and go with calsaway or aqualabz' ecoklear method. I did find calsaway's patent online. It appears they're using a modified lime softening method with a cationic polymer flocculant to settle it out.