Low Ph/high Alkalinity

[Andrew61987]

Hi

I have a 20,000 gallon vinyl lined pool. The problem I'm having is cloudy dull water with slight algae that is very difficult to brush off. A couple days ago my TA was was over 200 and pH was I think about 7.4. Messing around with it (mostly just adding HCl) I have gotten my TA down to about 160-170 but my pH is about 6.8.

Some other information:

CYA: 60ppm

TDS: 1000ppm

As it stands I'm trying to balance out the pH and TA by disconnecting my sweep and taking the hose for it out of the pool and shooting it back into the pool in an arc to try and aerate the water pulling CO2 out via concentration gradient to the air. How long does something like this take? I did it for about 8 hours yesterday and it's been going another 8 hours today and I haven't noticed much of a result with my drop based TA and pH test kit. Water is still cloudy and dull.

I have tried blue clarifier and shock to no avail. I am using granulated chlorine (Chlor-Brite I think?) to sanitize.

I don't know if I'll ever be able to get my pH and TA in check, and even if I do, I don't even know for sure if it will solve my dull cloudy water problem.

[JOSH D]

Hi

I have a 20,000 gallon vinyl lined pool. The problem I'm having is cloudy dull water with slight algae that is very difficult to brush off. A couple days ago my TA was was over 200 and pH was I think about 7.4. Messing around with it (mostly just adding HCl) I have gotten my TA down to about 160-170 but my pH is about 6.8.

Some other information:

CYA: 60ppm

TDS: 1000ppm

As it stands I'm trying to balance out the pH and TA by disconnecting my sweep and taking the hose for it out of the pool and shooting it back into the pool in an arc to try and aerate the water pulling CO2 out via concentration gradient to the air. How long does something like this take? I did it for about 8 hours yesterday and it's been going another 8 hours today and I haven't noticed much of a result with my drop based TA and pH test kit. Water is still cloudy and dull.

I have tried blue clarifier and shock to no avail. I am using granulated chlorine (Chlor-Brite I think?) to sanitize.

I don't know if I'll ever be able to get my pH and TA in check, and even if I do, I don't even know for sure if it will solve my dull cloudy water problem.

common vinly pool promblem here. easy fix. you can flock the pool w/ a fluctant agent following directions and the flock. some flocks will need 4-6 hrs circulation the shut the pool off and let the flock settle to the bottom. then vac the flock up and backwash the filter so the flock won't set up inside the filter. follow the direction on the flock. this should clear the pool up. once the pool is clear the TA should correct itself. and since the TA contols the PH the PH should fall into balance after the pool is clear.

[JOSH D]

Hi

I have a 20,000 gallon vinyl lined pool. The problem I'm having is cloudy dull water with slight algae that is very difficult to brush off. A couple days ago my TA was was over 200 and pH was I think about 7.4. Messing around with it (mostly just adding HCl) I have gotten my TA down to about 160-170 but my pH is about 6.8.

Some other information:

CYA: 60ppm

TDS: 1000ppm

As it stands I'm trying to balance out the pH and TA by disconnecting my sweep and taking the hose for it out of the pool and shooting it back into the pool in an arc to try and aerate the water pulling CO2 out via concentration gradient to the air. How long does something like this take? I did it for about 8 hours yesterday and it's been going another 8 hours today and I haven't noticed much of a result with my drop based TA and pH test kit. Water is still cloudy and dull.

I have tried blue clarifier and shock to no avail. I am using granulated chlorine (Chlor-Brite I think?) to sanitize.

I don't know if I'll ever be able to get my pH and TA in check, and even if I do, I don't even know for sure if it will solve my dull cloudy water problem.

common vinly pool promblem here. easy fix. you can flock the pool w/ a fluctant agent following directions and the flock. some flocks will need 4-6 hrs circulation the shut the pool off and let the flock settle to the bottom. then vac the flock up and backwash the filter so the flock won't set up inside the filter. follow the direction on the flock. this should clear the pool up. once the pool is clear the TA should correct itself. and since the TA contols the PH the PH should fall into balance after the pool is clear.

[chem geek]

The floc will help since most above-ground vinyl pools do not have a floor drain. You'll need to be able to vacuum to waste to remove what settles to the bottom of the pool. However, to kill the algae, you need to get the Free Chlorine (FC) level of the pool up to 40% of the CYA level. Chlor-Brite (if this product) is Dichlor where for every 10 ppm FC it also adds 9 ppm to CYA. You never, ever use this for shocking the pool! It is the most irresponsible chlorine product on the market (to be used as a shock). Increasing the CYA level makes killing the algae take even longer since it is the ratio of FC to CYA that determines chlorine's effectiveness. You want to shock with an unstabilized source of chlorine -- usually chlorinating liquid or unscented 6% bleach though if the Calcium Hardness (CH) level isn't high you can use Cal-Hypo. Regardless of the source of chlorine, it should be added very slowly over a return flow with the pump running (Cal-Hypo usually needs to be pre-dissolved in a bucket first) and then lightly brush the side and bottom of the pool where you add it to prevent any settling and to ensure thorough mixing.

Killing algae requires a constantly maintained high FC level, unless you want to use an algaecide. A copper-based algaecide will kill algae quickly, but then you are left with copper that can stain and make blond hair greenish. Chlorine alone can kill algae and clear a pool as seen here, but in a pool without a floor drain a floc is useful to speed up the clearing, but only after the algae has first been killed with chlorine (i.e. when there is no more green and you are just removing cloudiness which is dead algae).

By the way, the worst thing for a vinyl pool is acidity so I would raise the pH at least some to 7.0 if not 7.2 and if aeration lets you do that then great -- otherwise you can use some 20 Mule Team Borax which will raise the pH without raising the TA as much. I wouldn't worry so much about your higher TA until you've completely cleared the pool of algae. When you shock with unstabilized chlorine, the pH will rise, but it will come back down as the FC drops (unless the high TA keeps it higher). Remember that at high FC levels the pH test will not be accurate, though usually shows a higher pH than the true pH.

To prevent algae from growing in the future you either need to maintain a minimum FC that is 7.5% of the CYA level (10% is easier to remember and a safer target) or you need to use a supplemental algaecide such as PolyQuat 60 or a phosphate remover.