Ph just keeps falling

[da_guy2]

FC 16
Ph 7.0
TA 100
CH 100
CYA 80

I started the year with a Ph of 7.2., so I aerated for a week and brought it up to 7.6. I was told then that should watch and make sure the Ph doesn't go any higher as it has a tendency to rise with SWG pools. Well over the last few weeks I've slowly watched the Ph fall, and it's now down to 7.0.

So first, why does it keep falling? Is this normal? Am I doing something wrong?

Second how important is it to bring it back up?

Lastly, if I do need to bring it up, is aerating my only option? I don't really want my TA to get much higher.

(P.S. I know my FC is a little high, I'm just coming down off a shock and I'm trying to get my generator dialled in again)

 

[Deb04]

I have the same issue, so curious to see what others say. I think mine is caused by needing to do a lot of topping off (evaporation and possibly a leak) with water from my well, which has a pH of 6.9. I've also been adding CYA, which lowers pH. Have you been adding water? To raise pH I've been doing a combo of aerating and borax. Borax will raise TA a little, so maybe not a solution for you.

 

[pooldv]

With TA at 100 and an SWG I would expect PH to rise. Does your fill water have low PH? Have you had much evaporation? Or acid rain?

Aeration or borax are the best ways to raise it. It is important to keep it 7.2 or higher. Having your TA go up is not an issue if it doesn't cause your PH to rise.

 

[da_guy2]

I haven't been filling much this year (only once) and our fill water is supposed to be fairly basic here in Ottawa (>8.5) though I've never tested it myself. It's been a bad year for evaporation, but I keep a solar blanket on so that reduces evaporation some. It's also been rather dry so I doubt it's acid rain.

Just to confirm the main problem of TA being too high is that it will generally cause the Ph to slowly rise. That said if my Ph is slowly falling right now, then maybe a little more TA might be a good thing?

Also, I don't really have time to aerate the Ph up again so I guess I'm going to need to use a chemical method of raising. it. What's the advantage of using borax to raise Ph vs soda ash? Does one raise the TA more than the other? I can get the soda ash (pool ph booster from the local hardware store) for 1/3 the amount of the borax so if there isn't a significant advantage to the borax I think I'd prefer to use the soda ash.

 

[Mr Bruce]

Washing soda increases pH and TA more, by a lot. Check out the Effects of adding chemicals section at the bottom of pool math.

I'd check the pH of that fill water.

 

[da_guy2]

Washing soda increases pH and TA more, by a lot. Check out the Effects of adding chemicals section at the bottom of pool math.

I'd check the pH of that fill water.

Oh ya, I've never seen that section before. So soda ash would add more or less twice as much TA as the Borax so I guess that's reason enough to go with the borax. Too bad it's so expensive here in Canada.

As for the Ph of fill water, I use standard Ottawa tap water. According to the city, they Ph adjust it to between 8.4 and 9.2 so that it's not corrosive to pipes and in turn doesn't leach lead into the water system. I'd be VERY surprised if it's that much lower

 

[domct203]

Oh ya, I've never seen that section before. So soda ash would add more or less twice as much TA as the Borax so I guess that's reason enough to go with the borax. Too bad it's so expensive here in Canada.

As for the Ph of fill water, I use standard Ottawa tap water. According to the city, they Ph adjust it to between 8.4 and 9.2 so that it's not corrosive to pipes and in turn doesn't leach lead into the water system. I'd be VERY surprised if it's that much lower

One thing I've learned here at TFP is to never assume anything (Felix Unger had a great explanation why), check that PH yourself to positively rule out your fill water as a source of your PH falling.

According to your signature info, you've had this pool for a few seasons now, has the PH always fallen, or is this something new?

How do you chlorinate the pool, and what do you routinely add to the pool besides chlorine?

How do you test your water (what test kit do you have)?

Any recent pool $tore potions?

Dom

 

[da_guy2]

One thing I've learned here at TFP is to never assume anything (Felix Unger had a great explanation why), check that PH yourself to positively rule out your fill water as a source of your PH falling.

According to your signature info, you've had this pool for a few seasons now, has the PH always fallen, or is this something new?

How do you chlorinate the pool, and what do you routinely add to the pool besides chlorine?

How do you test your water (what test kit do you have)?

Any recent pool $tore potions?

Dom

Last year I accidentally raised the TA a bit too high (140). I was told it would likely cause my PH to slowly rise, but it held steady around 7.4 all year. So maybe had my TA been lower to start with it would have fallen last year as well? Not sure. In the past years, I haven't had any problems with Ph.

This year all I've added to the pool was Salt, CYA, and a few gallons of chlorine to shock.

As for testing, I test every 1-2 days with strips and 1-2 weeks with a K-2006 test kit. So far the test strip numbers more or less line up with the test kit.

 

[pooldv]

Yes, raise that TA a bit and see what happens.

 

[da_guy2]

My Father had another idea I thought I'd run by you. Right behind the pool is an oak tree that regularly drops leaves in the pool. It's not like the pool is full of oak leaves but there's always some in there no matter how often I clean them out. Well, it turns out that oak leaves can be somewhat acidic. Could this be the reason the Ph keeps falling?

 

[domct203]

My Father had another idea I thought I'd run by you. Right behind the pool is an oak tree that regularly drops leaves in the pool. It's not like the pool is full of oak leaves but there's always some in there no matter how often I clean them out. Well, it turns out that oak leaves can be somewhat acidic. Could this be the reason the Ph keeps falling?

That's a great theory, but I would think you would need an awful lot of leaves steeping for some time to effect 17K gallons.......

Interesting non the less, you never know ........

Dom

 

[Cinic]

I'd bet that yours if one of the pools that just prefers a higher TA. As others have said, bump it up and see what happens.