Calcium Hardness Test result very different TF-100 vs. Leslie's pool Shop

[rimmi2002]

Hi I just started taking care of my pool.

I just got the TFT-100 kit. Almost all chemistries were as expected on the first test except CH was measured at 300. On my last check at the pool shop the CH was 150. I was surprised. I took pool water to the shop again today and again all chemistries from the Kit were similar to the Leslie's Pool Shop. Except they measured a CH of 170.

I brought the same water home and tested it again and calcium hardness tested at 300 again. Any reason why this is? Can the reagents be bad? I also bought the mini stir magnet kit so reagents are mixing well. I ran all the other tests again today and the Ph, Chlorine, Alkalinity are same in store and via kit.

Any help would be great. Thanks.

 

[Jimrahbe]

Rim,

Just because the pool store gets a different number does not make them correct.

I doubt there is anything wrong with your reagents.

I see no reason not to trust your TF-100 and distrust the pool store tests.

Thanks,

Jim R.