Battling High TA - on the losing end

[IkeRay]

first off, some test results for you all:

FC - 3.0ppm
CC - 0.0ppm
pH - 7.8 (added 1 gal acid)
TA - 180
CH - 150
CYA - <30 (probably closer to 15-20)

so I like running low CYA, it allows me to run low FC so I don't get any chlorine smell/taste while swimming, I'm raising it closer to 30 currently with trichlor tabs (4 8oz tabs raise it ~5ppm, I'm on my second batch of 4). calcium I'll handle as CYA gets closer to its level, I'll be using 50lbs of cal-hypo over the next 1 1/2 month for shock and maintenance chlorine, should raise my CH by 115ppm, but the stickler is I can't lower my TA by adding a chemical, and it doesn't want to drop for me. I've added 1-2 gallons of acid over the course of a week and still can't get it to drop. any suggestions, I know aeration, any suggestions for an aerator?

 

[frustratedpoolmom]

Aeration doesn't lower TA - it's the combination of Acid additions, which lower both the PH and TA, and then aeration raises the PH back up where you want it.

For instance - calculate a dose on the PH of 7.0-7.2 - and add that much acid. Then aerate to raise the PH back up to 7.6, then repeat the acid additions, with the aeration. The acid additions WILL eventually lower the TA into range.

If you are not lowering the PH low enough - that could be why you aren't seeing movement. Also, if your fill water is high in TA and you are always replacing water, or have an autofill system, that could contribute to the problem.

As for aerators - if you do a "google search" -bottom left corner for aerator - there have been lots of suggestions and even some pics - check those out and maybe you'll find something there....

 

[257WbyMag]

Hi Ike,

It kinda makes me wonder how you have managed to avoid getting algae in the hot Texas summers by running a low CYA and FC like that. But if it's working for you, who am I to say different.

You lower your TA with acid additions, followed by aeration to raise the pH back enough that you are then able to add acid again. This process is repeated until you get your TA where you want it. It can take a long time to get it where you want it.

Two things...Number 1, if you have been using trichlor tablets, these are acidic and will keep your pH on the low side to the point where acid additions may rarely be indicated, if at all. Number 2, if your fill water has a high TA, you may find yourself chasing it despite your acid additions. Have you checked your fill water to see what the TA is? Keep in mind also that the TA in fill water isn't always constant. Depending on the time of year and your municipal water sources, it can vary a bit.

Aeration can be accomplished several ways. You can direct a return to the point where it breaks the surface of the water, causing bubbles. If you have a waterfall, that can work. Lots of kids splashing in the pool can do it too. You can also use an air compressor to create bubbles under the surface. Several times a year, we see some fairly ingenious aerators that have been created to accomplish what you are trying to do.

 

[IkeRay]

Hi Ike,

It kinda makes me wonder how you have managed to avoid getting algae in the hot Texas summers by running a low CYA and FC like that. But if it's working for you, who am I to say different.

Two things...Number 1, if you have been using trichlor tablets, these are acidic and will keep your pH on the low side to the point where acid additions may rarely be indicated, if at all. Number 2, if your fill water has a high TA, you may find yourself chasing it despite your acid additions. Have you checked your fill water to see what the TA is? Keep in mind also that the TA in fill water isn't always constant. Depending on the time of year and your municipal water sources, it can vary a bit.

yeah, typically I don't have a problem, but sometimes after rain or if I forget to pour bleach in a certain corner (see my black algae thread) I'll get a black algae colony starting in the corner (always the same corner), other than that I never have bad algae (or hardly any actually), I maybe backwash once a month, I'd say that means not much dead algae going through.

municipal source is changing from well to surface water, don't know when, but I can't remember last time I checked it (maybe 6 months ago), it was on the high side, but not 200ppm high, more like 150-160ppm.

 

[dmanb2b]

fyi...that chlorine smell does not come from higher FC levels as long as there is enough CYA to offset it. It's the CC's that give off that chlorine odor. We run our pool around 7-8ppm FC with CYA levels around 60-80...CC's are always les than 0.5ppm...most folks comment saying, I love your salt pool...it doesn't have that chlorine smell.. :blah: ...I don't bother trying to explain that a salt pool is a chlorine pool

Don't give up on your TA...I lowered ours from 300+...in your size pool it will take several gallons of acid additions...here is a link to an aerator I made out of PVC and some sch40 fittings (screwed right into my return)...just drilled the end cap a whole bunch of times to make a showerhead type of cap....lowered PH with Muratic acid to 7.0...aearate to raise PH to 7.6...repeat...took 8 gallons for me over a 2-3 day period with aggresive aeration. The acid lowers PH and TA....the aeration raises PH without raising TA. Good luck

http://s702.photobucket.com/albums/ww30/dmanb2b/?action=view&current=CopyofIMG_1066.jpg

 

[257WbyMag]

I just put two and two together and saw your other thread regarding the black algae issue. This is the herald mark that would indicate you need to up your FC and CYA. dmanb2b is correct. It is the CCs that make your pool smell like chlorine. Properly chlorinated water smells little different than spring water.

So yes, the TA in your fill water varies, but you know that it is higher than where you want your pool to be. That being said, it remains a process of acid additions and periods of aeration in series until you get the TA that you want. You don't have much control on what your fill water delivers, but you have lots of control when it comes to fixing it after it arrives in your pool.

 

[IkeRay]

I just put two and two together and saw your other thread regarding the black algae issue. This is the herald mark that would indicate you need to up your FC and CYA. dmanb2b is correct. It is the CCs that make your pool smell like chlorine. Properly chlorinated water smells little different than spring water.

So yes, the TA in your fill water varies, but you know that it is higher than where you want your pool to be. That being said, it remains a process of acid additions and periods of aeration in series until you get the TA that you want. You don't have much control on what your fill water delivers, but you have lots of control when it comes to fixing it after it arrives in your pool.

well, I do believe the black algae is an issue of circulation because as long as I keep the chlorine level above 1.5ppm (typically 2-3ppm) I don't get any algae in the pool except for that corner, if I pour 1/4-1/2 gallon into that corner during addition, pool looks good.

its not so much the smell (I conveyed that wrong) its the burning eyes.

I just vacuumed up the bottom of the pool end of march so the fill was running the whole time I was doing that (1-2 hours), so about 1000-1500 gallons or 4-5% of my water. took your advice and tested my fill water......TA - 530ppm, CH 50ppm, pH 8.0 ish. I've added 2 gallons of acid since this post was started (down to 7.0 up to 7.4, back down to 7.0), don't have anything for aeration yet but high TA typically makes pH climb rather quickly, if I let the pH naturally come back up, will this leave my TA low or will the TA increase with the pH?

 

[PaulR]

its not so much the smell (I conveyed that wrong) its the burning eyes.

That's still the CCs not the FC.

I've added 2 gallons of acid since this post was started (down to 7.0 up to 7.4, back down to 7.0), don't have anything for aeration yet but high TA typically makes pH climb rather quickly, if I let the pH naturally come back up, will this leave my TA low or will the TA increase with the pH?

As long as the pH rises without you adding any chems, the TA will not rise with it. The pH-rise process is the same--CO2 outgassing--aeration just makes the process go faster, it's not a requirement.
--paulr

 

[IkeRay]

That's still the CCs not the FC.

didn't know that, I'll have to talk to my brother and FIL about shocking more often since they're so insistent on trichlor, I've tried to convert them to BBB but no luck...

As long as the pH rises without you adding any chems, the TA will not rise with it. The pH-rise process is the same--CO2 outgassing--aeration just makes the process go faster, it's not a requirement.
--paulr

awesome, so for the time being I'll allow the water to do the adjusting until I can get my aerator fabricated, with a fill water TA of 500+ppm, I'll definitely need to do adjusting anytime I have to top her off.

 

[JohnT]

its not so much the smell (I conveyed that wrong) its the burning eyes.

If you can smell chlorine or it burns your eyes, you don't have enough chlorine in the water. We have well water, and if I go to a restaurant, I can smell the chlorine when they start filling the water glasses, but I rarely get a whiff of it in my pool with 5ppm FC.

 

[frustratedpoolmom]

That's still the CCs not the FC.

didn't know that, I'll have to talk to my brother and FIL about shocking more often since they're so insistent on trichlor, I've tried to convert them to BBB but no luck...

They shouldn't have to shock more often just cuz they use trichlor. It's okay to use trichlor tablets, but sometimes the trichlor just doesn't maintain the FC high enough to prevent the algae from setting in and to prevent the CC's from climbing. If they supplement with a little liquid chlorine to keep the FC above the "min" at all times their CC reading should consistently be below .5 . If they see higher CCs then that, it likely means they aren't maintaining the proper FC levels.

 

[257WbyMag]

well, I do believe the black algae is an issue of circulation because as long as I keep the chlorine level above 1.5ppm (typically 2-3ppm) I don't get any algae in the pool except for that corner, if I pour 1/4-1/2 gallon into that corner during addition, pool looks good.

Lack of good circulation can play a part. That's for sure. But properly chlorinated water that doesn't circulate well will still not allow algae to grow.

Black algae, any algae for that matter, can be persistent. Black algae is especially so. It takes high doses of chlorine, frequent brushing, and more high doses of chlorine to get rid of it. The fact that it keeps reappearing makes me think that it has never really been eliminated in the first place. Rather, it is waxing and waning with the variable FC levels in your pool.

Trichlor can keep the peace in a pool that doesn't currently have problems. When a battle needs to be waged against algae, trichlor won't get the job done because it is simply too slow to effect a solution. That's why we recommend bleach because the FC is immediately available, all at once.

 

[poolgirl22]

Aerator/Fountain which I'm so proud....

Submersible pump, attach water hose. Attach sprinkler head to hose. Aim at water surface. Plug in.
Here's a pic. I happened to have a pump to drain my winter cover. I blew the dust off an old sprinkler. I thankfully had a hose which had an end to attach a sprinkler to...not an easy thing to come by with a jack russel terrier in the house...she thinks hoses are snakes I think.

I also pointed my return up. I run this the same time as the pump..12 hrs a day. It takes about 2-3 days for my PH to go back up to 7.6 - 7.8 after I add acid to bring it down to 7.2. I'm on week 3 and I've brought my TA down nearly 100 ppm.

 

[dmanb2b]

That's still the CCs not the FC.

ditto...no burning eyes and we do not use gogles...balanced water does not smell or burn eyes...low CC's and PH between 7.4 and 7.6 is what you want

 

[IkeRay]

some progress, waiting on pH to climb back up, it was at 7.0ish this morning but TA has definitely dropped drastically. TA is reading just under 150ppm (using 10mL sample to save reagents, will do 25mL sample when closer to 100ppm). thank you all for the help, I have to do a dye test this weekend (and some ping pong balls maybe) as per my circulation issue, but at least I'm finally seeing a drop in my TA and know the key source - dang fill water!

I love the members of TFP, also helpful and never harsh, hopefully I can report back with positive results when it all gets resolved.