Wrong starting point for filling the pool?

[SteveE]

Hi all,

I'm trying to figure out if I made the right choice when I filled the pool.

For background, we live in an area that requires well water, and our water has quite a bit of iron. I run the softener with the iron reducing pellets, but if the softener gets low on salt, or if I put in the normal pellets, then we get hard water stains in the toilets and sinks within a day or two.

So when it came time to fill the pool, I decided on using soft water instead of the hard. I thought the water would feel much nicer, and be able to avoid having the iron in the pool.

So the pool has been up for 2 weeks, and has stayed clean and clear so far. I monitor the chlorine and pH each day, and have been successful controlling those. I also added the CYA, and it has remained at around 50 ppm.

I don't have one of the really good test kits (yet), but I did get the HTH kit from WalMart. The reasons for questioning my decision are 1) alkalinity and 2) total hardness. My alkalinity was initially 350, and my total hardness was ZERO.

So I've been working on getting the TA down (thanks to JasonLion for the latest pool calculator, which helped me realize how much muriatic acid I need) by adding the acid and aerating the water to keep the pH in line. But I realize that this is going to take awhile!

My total hardness is now about 30, as I've been replacing lost pool water from the well. I guess I will try to find the best method for raising hardness after getting TA where I need it.

But would TA and total hardness have been better by using the well water from the beginning? Would fighting iron (and maybe other metals? I'm not sure) have been the easier fight?

This isn't a topic (hard water vs. soft water) I've seen discussed much, so even if I chose incorrectly maybe your answers will help others with the choice if it is an option.

 

[Buggsw]

It's a vinyl pool, right? You don't need to worry about CH at all, according to many here.

I think it sounds like you made an excellent choice. So many owner's who have well water, fight the discoloration of water and other surfaces from metals in the water. So, if your subsequent fill water is not going through the metal filtering type pellets, you will want to have some metal sequestreant like Jack's Metal Magic on hand.

Also, the HTH test kits are fine, to use - the only problem with them is they usually don't measure as many things as we like to see - such as CC's. Otherwise, I find they are decent OTO kits.

 

[Guest]

Using the softened water was the right choice. I would also refil from the softened water so you do not get problems with iron staining. A water softener will not affect TA so if your fill water has high TA you will need to keep tabs on it when you need to add water to the pool.
The main reason you need some hardness in a vinyl pool is to help reduce foaming. (Soft water will foam more easily than hard.) I would add enough calcium to bring the calcium hardness to abut 130 ppm.

 

[SteveE]

Thanks for the help. Yes, vinyl pool. I guess I thought the softened water may have contributed to the alkalinity. You both bring up a good point about topping off the pool with well water - I'll go back to the softened water.

Also, even though my water hardness is basically zero, I haven't had any issues with foaming. My test kit is only looking for total hardness - is it possible that it can't detect calcium hardness at all? I was thinking calcium hardness would show up as a portion of total hardness.

 

[Guest]

Total hardness is the sum of the calcium and magnesium hardness. Calcium hardness is the only type we are really interested in with a pool so a total hardness test is useless. Are you using test strips perhaps? They only test total hardness while the majority of drop based kits test calcium hardness.

 

[SteveE]

Waterbear

I have the 6-way HTH test kit from walmart. Reading in detail, the instructions are unclear - they seem to contradict themselves! Basically,add 25 ml of pool water to beaker, add 5 drops of indicator (water turns red if hardness present), then add indicator 1 drop at a time until water turns blue. Pretty straightforward.

The instructions for each type of test are color coded, so that the appropriate instructions match the color on the chemical bottles. Anyway, the instructions I am referring to are labeled "Total Hardness", and are described as follows:

"Total hardness is the measurement of calcium and magnesium carbonate in your pool or spa water."

However, at the end of the instructions, this statement is found:

"Multiply drops in Step 3 by 10. Record as parts per million (ppm) total hardness as calcium carbonate"

So maybe this is really testing for calcium hardness, and the initial description is incorrect?

When I first filled up the pool and added the indicator, the sample water turned blue indicating zero hardness. The last time I tested, it took 3 drops to get the sample blue, so it had increased to 30ppm, I assume from adding well water to compensate for splash-out.

 

[Guest]

sounds like a total hardness test. Most calcium hardness tests use three reagents and total hardnes tests use two.