Why is my pool so dirty!!!

[Charrua2]

Alex,

If you lower your TA, then you make the water more corrosive in terms of gunite/plaster/grout so you would need to compensate by increasing Calcium Hardness (CH) or keeping the pH higher or both. However, you generally don't run into problems with corrosion (or scaling, in the other direction) until the saturation index is quite a bit out of whack. Nevertheless, if you post a full set of numbers, especially for your pH, CH, CYA, salt level or TDS, current TA, and temperature, then I can give you an idea of where you are currently at and what you can do after lowering the TA.

Richard

Thanks Richard,

Haven't tested the water since I closed it but I can tell you that the numbers usually were as follows:

FC = 2-5 (I rarely shock)
CC = 0
CYA = 40
Salt level or TDS = ? (never tested for this)
TA = 100 - 120 (used to be 90 and I raised it to 120...After that it lowers when I add the acid but then creeps up)
PH = 7.6 - 8.0 (added acid once a week...PH always creeped up but the upswing was quicker after I increased the TA)
CH = 350
Water temp = 75-90 degrees depending on month

Other info that might be of use: I only use bleach and I don't have a heater.

Thanks again

[chem geek]

Charrura2,

In your situation, you can lower your TA to 80 or even 70 with absolutely no problems (even if you did have a heater, which you don't). You can do that (following the procedure at this post) when the temps come back up since trying to lower your TA when temps are low can be more difficult. The lower TA will definitely help your battle of rising pH and you should be able to keep your pH around 7.5 without too much difficulty. Your CH is already elevated at 350 and helps compensate for the lower TA that I am proposing so your water will be in near perfect balance at the lower TA levels (currently, your water is over-saturated with calcium carbonate, but not so much as to cause cloudiness or scaling).

Richard

[Charrua2]

Charrura2,

In your situation, you can lower your TA to 80 or even 70 with absolutely no problems (even if you did have a heater, which you don't). You can do that (following the procedure at this post) when the temps come back up since trying to lower your TA when temps are low can be more difficult. The lower TA will definitely help your battle of rising pH and you should be able to keep your pH around 7.5 without too much difficulty. Your CH is already elevated at 350 and helps compensate for the lower TA that I am proposing so your water will be in near perfect balance at the lower TA levels (currently, your water is over-saturated with calcium carbonate, but not so much as to cause cloudiness or scaling).

Richard

Thanks Richard,

I had read in another post where someone even lowered there TA to 50 to really fight the rising PH. Next summer, if I see that TA of 70 still doesn't do the trick, can I try lower or should I avoid the risk?

Promise this is the last question.

Thanks again

Alex

[chem geek]

Remember that TA is composed of all alkalinity, both carbonate alkalinity and the alkalinity from CYA (and other lesser components) so even 70 ppm TA is risky if the CYA is high (i.e. 70-80) while at a lower CYA of 30 ppm then 70 ppm is OK. A 50 ppm TA even with a low CYA of 30 ppm, is on the corrosive side (not terribly -- just my being picky), and though this can be mitigated by running a higher CH and a higher pH, I would only do that if the rising pH was a really bad problem. At 50 ppm TA, a CH of 400 and a pH of 7.6 (instead of 7.5) would be better.

Richard

[Charrua2]

Remember that TA is composed of all alkalinity, both carbonate alkalinity and the alkalinity from CYA (and other lesser components) so even 70 ppm TA is risky if the CYA is high (i.e. 70-80) while at a lower CYA of 30 ppm then 70 ppm is OK. A 50 ppm TA even with a low CYA of 30 ppm, is on the corrosive side (not terribly -- just my being picky), and though this can be mitigated by running a higher CH and a higher pH, I would only do that if the rising pH was a really bad problem. At 50 ppm TA, a CH of 400 and a pH of 7.6 (instead of 7.5) would be better.

Richard

Ok, so it looks like if I go the route of lowering the TA to 70, I will have to keep on top of the CH a bit more than in the past. It's something I used to test once a month since it never really seemed to move way out of wack (ie, always between 300-400).

We'll see how it goes next year. Thanks once again.

[Charrua2]

Remember that TA is composed of all alkalinity, both carbonate alkalinity and the alkalinity from CYA (and other lesser components) so even 70 ppm TA is risky if the CYA is high (i.e. 70-80) while at a lower CYA of 30 ppm then 70 ppm is OK. A 50 ppm TA even with a low CYA of 30 ppm, is on the corrosive side (not terribly -- just my being picky), and though this can be mitigated by running a higher CH and a higher pH, I would only do that if the rising pH was a really bad problem. At 50 ppm TA, a CH of 400 and a pH of 7.6 (instead of 7.5) would be better.

Richard

Richard,

I opened my pool this season and am in the process of lowering the TA to 70 (as mentioned above). One number that changed over the winter season is the CH which is now at 175. I have purchased 8 llbs of Calcium Increaser from Walmart which should raise the CH to approx. 200. Should I raise it more or keep it there. My guess is that CYA is at appox 20 (dot never disappears completely but FC has not diminished too quickly). What do you think? As always, thank you.

Alex

[chem geek]

If you want to have your pH closer to 7.5, then I would raise your CH level to around 300 ppm. Otherwise, you could just run your pH around 7.7 at your current CH level of 175 and be fine. It's not a big deal either way -- I'm just letting you know what is closer to ideal. Having your pH target at 7.7 would result in even less rise in pH, but if you don't see much of a rise at 7.5 and want that as your target instead, then the higher CH level would be better (but not a huge problem if you didn't do it -- the saturation index at pH 7.5, CH 175, TA 70 and CYA 20 is about -0.3).

Richard