Are My Numbers Ok

[gary3029]

Hi

Well up and running with the new tub. Using the bromine system and it seems ok at present. Just want to check if my numbers are ok given I am dictated by my CH. We have very hard water here so tap water was well over the 400 Mark. Used a filter on the hose to fill the tub and my CH is now 300. My TA is 60 and my PH is settling at 7.5. Temp is 40c and size is 1022 litres. I know nothing but it would appear by working to my CH because I cannot lower this my SI appears balanced. Would I be correct in assuming this?

Also I use the Lamotte tablet test kit as cannot get Taylor in the uk. When looking for colour change in the CH and TA test am I taking the reading as soon as there is a slight change or a definite change?

Thanks

Gary

[waterbear]

Hi

Well up and running with the new tub. Using the bromine system and it seems ok at present. Just want to check if my numbers are ok given I am dictated by my CH. We have very hard water here so tap water was well over the 400 Mark. Used a filter on the hose to fill the tub and my CH is now 300. My TA is 60 and my PH is settling at 7.5. Temp is 40c and size is 1022 litres. I know nothing but it would appear by working to my CH because I cannot lower this my SI appears balanced. Would I be correct in assuming this?

Also I use the Lamotte tablet test kit as cannot get Taylor in the uk. When looking for colour change in the CH and TA test am I taking the reading as soon as there is a slight change or a definite change?

Thanks

Gary

How much above 400 is the CH? What kind of filter did you use to lower it (since I know of no inline filters that lower calcium hardness since it requires an ion exchange resin such as found in a water softener). Please post the actual numbers.so we can see where your SI really is. However, with high calcum pH control is the most important factor to prevent scaling. In most cases keeping the pH below about 7.7 is enough but it really depends on just how high your CH really is. The reason is because the factors in the equation to calculate SI that have the most impact are pH and then temperature (which is pretty much not an option in a hot tub). The Log(10) of CH and TA are used in the calculation so large changes in either really do not produce that much of a change in the SE compared to smaller changes in pH or temp.

With titration (drop counting) tests you add drops until one more drop produces no more color change and then you don't count the last drop. For example. you are titrating TA and the color starts to change on drop 7, you add another drop and it changes more on drop 8, you add another drop and there is no more color change on drop 9. You don't count drop 9 so your TA would be calculated with 8 drops. If your test has resolution of 1 drop = 10 ppm then your TA is 8 (drops) x 10 ppm = 80 ppm TA.

[gary3029]

Thanks for such a quick reply. I told you I know nothing. You think you are getting the hang of it and your not!

Ok have repeated this test 3 times to make sure of my findings. Using my test kit I filled the tube upto the 400 mark with tap water and added the tablet. It remained pink 3 times which the kit says is over 400. Have no way of testing how much over 400 it is, but we get through a kettle on a yearly basis

Then did the pool water 3 times and it turned purple. I then added water until it went pink which was at 300. The hose filter I used was the Eco one filter. Not sure what it did, but it did something!!!

My numbers are Ph 7.5 TA 60. CH is 300 temp 40c

I wish I had the drop test kit as I am sure it is more precise than what I currently have , but the Lamotte has to be better than test strips. The company who produce the Taylor kit could make a killing if they would sell it in Europe.

Thanks.

[waterbear]

LaMotte makes good test kits. However, they make kits with tablets and also with liquid reagents. The liquid reagent kits are very similar to the Taylor kits. The dry reagent kits do have some limitations, IMHO. Their tablet basedcalcium hardness test has some limitations since it is a colormetric (color matching test) and not a true titration. They call it a back titration. It sounds like you have the Pool Manager test kit which uses the tablets and does the back titration and cannot read above 400 ppm. Their multitest DL series of kits and their PRO series of kits use liquid reagents and their TA and CH tests are basically identical with Taylor's and do not have an upper limit. YOu can dilute a sample of pool water with distilled water (which should have 0 ppm CH but I would test it first to be sure) and test to see if you are now in range and then double the test results to get a CH reading. If you are still testing above 400 ppm then your water is VERY hard.

The eco one filer is simply an active carbon drinking water filter of the type usually used for campers and their claim it changes calcite into aragonite (which is a different form of calcium carbonate scale is just hype unless IT IS ALSO INTRODUCING COPPER/ZINC INTO THE WATER! These metal can affect how the scale precipitates out and causes the formation of the aragonite form of calcium carbonate rather than the calcite form. However, it is not really removing the calcium, just changing the way the scale forms and it is also introducing additional metals into the water The ONLY way to remove calcium ions from the water is by ion exchange, distillation, adsorbtion media, or reverse osmosis.

Here is quote from a website describing the eco one filter:

"The ecoONE® Pre-Filter is a combination of granular activated carbon (GAC) and a patented reduction/oxidation media that is classified by the EPA as a bacteriostatic." (empahsis mine)

This strongly makes me suspect that the filter contains KDF granules, a copper/zinc alloy (aka brass) which is used in wastewater treatment and alsl in 'salt free water softeners' which have not been proven to work!

Metals are a known interference with the CH test and could account for the change you see since you are doing a back titration.

[gary3029]

Many thanks for such an in-depth answer and the research you have done. Thought I was doing right by putting my tap water through a filter. Have been through to Lamotte and ordered a new test kit. Hopefully this sort out what I really have. Thanks

[gary3029]

Hi waterbear

Have just got my color q pro7 and my readings were not that far off. Tap water CH was 440 and pool CH was 272. Is using the Eco filter causing me any long term problems? Thanks.

Gary

[waterbear]

bad new is that the colorq uses a colormetric test for CH so it sufferers from the same limitations as the one you alrady had, which is also colormetric and not a true titration. It is not one of the kits I recommended. The Pro series are drop based kits and do not use a colorimeter.