Confused about Alkalinity

[kikiganz]

I noticed something today that I would like to get clarification on. On the Recommended Levels document, on this site, a plaster pool shows Alkalinity should be 70-90+. I have been shooting for 80. However, I just noticed in my TF-100 kit it recommends 100-120.

I know Alkalinity and Ph are related and I have been having trouble for the last 10 days keeping my Ph down. I will get it down to 7.5 and it will start creeping back up until I have to adjust it back down.

Which should I follow and could the problem with my creeping Ph be that I am keeping my TA too low?

Thanks!
Kristina

Last night pH was at 8.0 so I added pH Minus (I am not comfortable with using Muriatic Acid). It is at 7.6 this morning and TA is at 60.

 

[cowboycasey]

Kristina, it is actually opposite, the lower TA will help stabilize your PH.. but your PH will still rise if you have a waterfall or a return pointed toward the water causing a ripple or a spillover spa... the lower TA will help but not stop PH rise...

if you use poolmath you want your CSI in the -0.3 to +0.3 range and as you put different numbers in your CSI will change

 

[kikiganz]

Ok...I usually do a full test on Sunday evenings but I guess I will go ahead and do now and see what the numbers look like? I don't have any kind of waterfall but can you calrify this part " a return pointed toward the water causing a ripple or a spillover spa...".

We did recently adjust our returns because the debris that floats on the top of the pool was just swirling in the deep end instead of making it to the skimmer and that has caused a slight water ripple on the surface in the deep end. Is your statement saying that could be the problem? Again, no waterfalls or anything like that. Just a regular "80's" kidney shaped like pool.

Thanks!
Kristina

 

[txnole]

I'm trying to remember but I believe you had some questions about chemicals earlier and indicated that you did have a quality test kit. If my memory is poor, please ensure that you are using the results from a good test kit (Taylor, TFT) and not pool store measurements. ��

TA is the measure of all the alkaline substances in the water (carbonates, bicarbonates, hydroxides, etc.) and acts as a buffer to pH. The levels your mentioned are the recommended for your gunnite/plaster pool ... 80 sounds great if you can maintain it there. (Some pools just tend to stick at certain levels.) I'm not sure what other chemicals your may be using but understand that the reason specific chemicals are recommended on the forum is that the effects are well understood without too many unwanted side effects. Muratic acid, for example, we know hits pH and TA, but doesn't give any unexpected impact on CYA, for example.

For your pH increase, there can be several factors including plaster curing on new pools (don't think this applies to you), aeration, impact of SWG, high TA levels, rain, and kids splashing. ���� Again, some pools just seem to "fit" into a certain number. Ideally you could monitor the cause over the course of a few days/tests and thus understand/anticipate the change.

There are some well regarded posters who will tell you not to worry too much about TA, rather to keep your pH in line and monitor your CSI instead. They are all inter-dependent, so I think both methods are probably sound. YMMV.

- - - Updated - - -

Ok...I usually do a full test on Sunday evenings but I guess I will go ahead and do now and see what the numbers look like? I don't have any kind of waterfall but can you calrify this part " a return pointed toward the water causing a ripple or a spillover spa...".

We did recently adjust our returns because the debris that floats on the top of the pool was just swirling in the deep end instead of making it to the skimmer and that has caused a slight water ripple on the surface in the deep end. Is your statement saying that could be the problem? Again, no waterfalls or anything like that. Just a regular "80's" kidney shaped like pool.

Thanks!
Kristina

I think the suggestion was to identify any aeration/splashing on the surface. Changing the direction if you're jets won't raise pH, unless the stream is breaking the surface and raining water down onto the pool.

 

[kikiganz]

I am using the TF-100 kit and haven't brought my water to the pool store since I found TFP. My understanding was that, while muriatic acid is preferred, dry acid is acceptable. So let me know if this is not acceptable.

Could it be my CYA causing my pH rise? Just did a full test which came up with the following:

FC: 4.5
CC: 0
pH: 7.6
CH: 225
AK: 60
CYA: 20

For the last four weeks, my CYA was at 40. Not sure why it has dropped so much suddenly other than it has been so hot and sunny this week we had a lot of evaporation and have had to fill the pool a lot.

Oh...and that CSI says -0.14 and -0.06.

 

[cowboycasey]

ahhh, new fill water, that could be the cause of your PH rise also and but will have no impact on CYA unless water was taken out of the pool.. yes, just a little ripple can raise your PH, not fast but it will have a slight effect on PH....

what is your tap water PH? was the hose ran into the pool or set on the side of the pool and let pour in?

 

[kikiganz]

What a dummy! It never occurred to me that the pH of my tap water could be high and thus causing my pool pH to rise!!! Just tested it and it seems to be about 8.0 (The pH test is so dang subjective especially on a bright sunny day...drives us crazy!).

The hose was dropped in the pool to fill. I am guessing, since you asked, that matters?

We didn't manually remove water from the pool but the evaporation was nuts this week so we definitely lost pool water. We started wondering if we had a leak but it just coincides so much with the hot, sunny days.

And just like that...everything is back out of control! And I was doing so good!!!!

 

[cowboycasey]

no issues, you're still doing great, you know what is happening, your tests are correct and you know what to do you are light years ahead of of someone that has not found TFP

GREAT JOB

 

[kikiganz]

Thanks cowboycasey... just a couple of final questions...

1. Does dropping the hose in the pool vs. having it sit on the side and pour in matter? I assume so since you specifically asked it but wanted to check cause I am not clear on which one is the "right way" and which one is the "wrong way".

2. "i think" i need to address my CYA asap and get some stabilizer in it. My FC is too high for the current CYA level but I am guessing that doesn't matter? Focus on getting CYA up?

3. My original question about alkalinity...TF-100 kit says 100-120 but TFP says 70-90+ (and what does 90+ mean anyway???) which should I follow?

4. Is there somewhere I can read about the CSI on the PoolMath and what to do to get it aligned?

5. Am I ok to continue using sodium bisulfate to lower my pH?

For the one millionth time, thanks again for everything!

Kristina

 

[cowboycasey]

Thanks cowboycasey... just a couple of final questions...

1. Does dropping the hose in the pool vs. having it sit on the side and pour in matter? I assume so since you specifically asked it but wanted to check cause I am not clear on which one is the "right way" and which one is the "wrong way". in the pool works better cause it won't add to the already high PH of your fill water

2. "i think" i need to address my CYA asap and get some stabilizer in it. My FC is too high for the current CYA level but I am guessing that doesn't matter? Focus on getting CYA up? In GA you would be good with a CYA of 40, you FC is fine, no need to worry..

3. My original question about alkalinity...TF-100 kit says 100-120 but TFP says 70-90+ (and what does 90+ mean anyway???) which should I follow? this one is dependant on "your" pool and what it needs, some pools like a lower TA and some like a higher TA.. the + means from TA70 to 120 and I am lower than that, my TA is at 50 and my PH stays right at 7.5/6 and I only have to lower with MA once this year

4. Is there somewhere I can read about the CSI on the PoolMath and what to do to get it aligned? this is about scaling but also has CSI data.. Pool School - Calcium Scaling

5. Am I ok to continue using sodium bisulfate to lower my pH? yes you can use it but it adds other things to your water and it's expensive.. MA is really better and if you float the bottle in the water and pour slowly in front of a return it is a non issue.. with that said do only what you feel is right for you

For the one millionth time, thanks again for everything!

Kristina

You are welcome