TA and PH Constantly Dropping?

[ccronje]

Hi guys,

I was wondering if anybody can advise on this issue.

I have a small in-ground fibreglass pool and for some reason I'm having a really hard time keeping the TA and PH stable. I would add the necessary chemicals to get the TA and PH to recommended levels and then it will immediately start dropping again slowly. After about a month the water would be very acidic if I don't do anything.

I've done a lot of searching online, but can't figure out what the cause of this could be.

Can anybody perhaps offer any explanations or suggestions?

Thanks

Chris

 

[257WbyMag]

Hi Chris, could you please post test results for the following: FC, CC, pH, TA, and calcium hardness? Also, are you operating a saltwater pool?

For what it's worth, pH is always changing in most any pool and usually, by rising. It is unusual for pH to continuously fall unless some sort of automated pH control system like an acid feeder (uuncommon) is acting up.

 

[duraleigh]

Hi, Chris,

just re-emphasizing what 257 said, we need some test results to comment in a meaningful way. If you are using pucks (a lot of them) to chlorinate, that is a likely suspect for your pH drop.

 

[ccronje]

Thanks for the quick responses.

It's not a saltwater pool. I've used bleach to shock the pool in the past, but otherwise I'm using standard granular chlorine found in the shops.

For the first couple of years that I had this pool there were no problems with the PH, then last summer this problem of the PH dropping suddenly started. The only changes I made to the pool around that time was that I installed solar heating, which keeps the water quite warm in the summer (between 28 and 32 degrees celcius). Any chance that this could somehow cause the problem?

Unfortunately I don't have access to a proper test kit here, so I'm just using the basic stuff available in pool shops. I just added chemicals to the pool today, but before that the TA was around 20 and the PH somewhere way below 6 (the lowest my test kit shows) and both dropping slowly. The FC is 5ppm, but I'd have to go and look for a different test kit in order to measure CC and Calcium Hardness.

Apologies for the lack of good test info.

Thanks

Chris

 

[UnderWaterVanya]

There are three types of chlorine that come in powder form that are commonly available:

Dichlor
Trichlor
Calhypo

The first two of these are bound with CYA which is acidic. Trichlor doesn't dissolve as well as Dichlor so it is more often used in solid pucks.

Calhypo is a calcium product that is not acidic.

It is possible that you may have used calhypo when the pH and TA were more stable and switched to Dichlor our trichlor without knowing it.

Continued use of any of these chlorine sources will eventually make it hard to maintain your pool without expensive measures or water changes.

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[UnderWaterVanya]

Could you read the before you post section in pool school and update your signature? Also what type of pool surface do you have?



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