CH Test Question

[DONNIE]

Thanks Richard. I was hoping you would see my post. My original fill was last month and about 50F. I have tried to keep my Ph at 7.5 but it wants to climb to 7.7 - 7.8 every 2 days. 7oz of muriatic acid every 48 hours seems to keep it at 7.5. I have been afraid to let it rise any higher as the water is beautiful.

Donnie

[DONNIE]

I do not have a cover by the way. As far as the red specks, they are exactly that. When it first starts from red to blue they appear. I have even added as much as 3 more drops with no further change to blue but the red specks remain.

From a search:

"One other thing-was this an error on my part or is this supposed to happen? When testing the Cal, there was a precipitate the same color as the water, just darker, swirling around the test container."
"This is normal. The first reagent in this test causes the magnesium in the water to precipitate out as magnesium hydroxide so you can get an accurate calcium hardness reading. The purple specks you are seing in the water is the magnesium hydroxide. The color of the water should be a definite blue. If it is still purple then you have not reached endpoint on this test. Keep adding drops and swirling until you get no more color change on adding a drop and don't count that last drop."

"Re- calcium hardness test. You win this one, the test is not complete until the color change is permanent. Those little purple specks in the water aren't the endpoint, you may have to add 10+ more drops to get the entire sample to change to the end color (the higher the reading, the more 'in between' drops there are - for both CH and TA)"

Donnie

[chem geek]

Cool. There are a lot of smart posters and useful information on this board. My water is probably not very hard so the initial fill probably didn't add a lot of magnesium so I don't see the specs that you do. It's nice to know they aren't a problem.

As for you pH rise, you can not only lower your TA to 90, but you can also add 50 ppm Borates as discussed in this thread. The combination of lower TA and having Borates seems to really do the trick. The lower TA means the pool is less carbonated so outgasses less carbon dioxide while the Borates are an additional pH buffer and are also an algaecide that lets you cut down your SWG production (since less chlorine gets used up killing algae) which lowers the hydrogen gas bubble aeration which lowers carbon dioxide outgassing. The pH rise is mostly due to carbon dioxide outgassing.

Richard

[DONNIE]

Richard, Is adding 7oz acid every 48 hours too much? Also.....after reading Waterbears borate thread it seems to add borates will increase my Ph so I add more acid to decrease Ph initally then it should stabilize and quit rising from 7.5 tp 7.7 every 2 days. I can't imagine trying to hold my Ph any lower.

Donnie

[chem geek]

Donnie,

Yes, you are right that adding Borax raises the pH so when this is initially done you add acid right after each addition so your pH won't change. Of course, once you've reached 50 ppm then you shouldn't need to add any more Borax (and associated acid) and it should stick around and not decrease, just like Calcium in CH (except for splash-out and backwash, of course).

Since adding 50 ppm Borates is easy to do, but hard to undo (drain and refill or continuous dilution), you might want to first just try getting your TA down to 90 since that should improve your situation. As for whether the amount of acid you are adding is "normal", it's really a matter of your convenience. If the time and cost doesn't bother you, then it's OK. If it's a problem, then know that lower TA and the use of Borates can help.

By the way, eventually your TA will drop over time due to your frequent additions of acid so if you don't want to drop your TA quickly through the Lowering Your Alkalinity procedure, then you can just be patient with what you are currently doing and you should see your TA drop and your acid usage drop (though it will take some time for this to occur). Just don't add any pH Up product that is Sodium Carbonate (nor Alkalinity Up that is Sodium Bicarbonate) or else you'll increase your TA and undo your progress.

Richard

[DONNIE]

Thanks Richard. I don't have any Ph up problem. I don't know how high it would go left unchecked. It's developed a pattern of a .2 RISE every 2 days so with my 9K gal pool its easy to adjust. I think I will continue with my program until water temps come up and I can fire up the SWG. I hate to keep saying it but my pool is so clear. I am not only amazed but so thankful to everybody on this forum. I was so overwhelmed at first, now it's so easy. I do believe that everyone who discovers this board feels the same way. Luckily I never tried anything else.

Donnie