Location, Climate and PH

[WalterE]

I am new and have a question about PH- Alkalinity and Location/Climate. When I had my pool in Dallas I always added Muriatic Acid to lower the PH. Almost weekly, dump some acid in the pool. Since I moved to Little Rock 10 years ago, I add no acid, but constantly add baking soda to raise the PH. Almost weekly. I know that Little Rock has acidic soil (very good for acid loving plants like Azaleas and Dogwoods) and the soil in Dallas is just the opposite (acid loving plants do not do well). Not sure why... maybe the rainfall?

I recently had a major problem with algea and just now have the pool clear again. But now, the PH is 7.0 to 7.1 and the Total Alkalinity is 150. I have not seen the alkalinity that high and the PH slightly lower than normal.

Any suggestions?

 

[jblizzle]

Welcome to TFP!!!

How did you chlorinate your pool in TX? How do you chlorinate your current pool?

What are you testing your water with?

Generally you do not need to worry much about the TA level. More important to keep the pH inline.

Could be that the pH of the tap water was very different between the 2 pools.

 

[WalterE]

I chlorinated both the same way. With 3 inch tablets (two floating dispensers) and shock once per week. Both from Sams Club.
Testing with an HTH test kit from Wal-Mart combined with a monthly visit to Lesley's to validate my measurements. (only testing Chlorine, PH and TA).
I've tried soda ash to raise my PH but it also increases the TA.
I have never tested the tap water either location. It's difficult for me to not suspect rain fall being different in each location (having heard of acid rain).
Thanks for your help.

 

[jblizzle]

Well, your current problems is the use of trichlor tablets ... they are VERY acidic and thus the reason for your pH dropping. And that is not the worst problem with them which is the fact that they raise your stabilizer level and if you do not raise the FC level to compensate you will have problems. I am guessing the TA in your fill water was MUCH higher in TX and thus the pH did not drop as much.

Also realize that pool store testing has proven to be horrendous and that you will save yourself a lot of aggravation and money by investing in one of the Recommended Test Kits and taking control of your pool using the methods we teach.

I can only imagine that your CYA (stabilizer) is WAY too high in your water and algae is in your future (if you do not already have it). And the weekly "shock" which we also do not recommend could be making the problem worse.

Have you discovered Pool School yet? Start with these:
ABCs of Water Chemistry
Recommended Pool Chemicals
How to Chlorinate Your Pool

 

[WalterE]

I will. Thank you.

 

[pooldv]

The best way to increase your PH without impacting TA is aeration or Borax, both are explained in the chemicals link Jason provided.

The reason for your PH/TA in Dallas is due to alkaline soils from the pervasive white rock and caliche rock which are calcium carbonate and lime and very alkaline as well as the black clay which is also slightly alkaline. This contributes alkalinity to all ground water sources. The soil in your area probably has more organic matter contributing to more acidic soils and ground water.

 

[WalterE]

Thanks pooldv, that confirms my suspicions. I also suspect that my plan of attack for adjusting PH and TA might be different for the two locations, since doing nothing in Dallas, the PH and TA would both naturally go up. The reverse happens here in LR. Doing nothing lowers the PH and TA. Currently I have a mismatch with the TA moderately high and the PH moderately low. It's difficult because most chemicals affect both PH and TA in the same direction. I am taking your advice and have the jets pointing up to aerate the pool. If that doesn't work, I'll try the Borax next.

Pools are interesting and complex. They seem to have a mind of their own. Great job on the forum. A ton of information.

 

[Agent99]

Of all the parameters we check for, TA is the least important so don't worry too much about it right now. As you'll soon learn, you have a couple other issues needing addressed and brought inline and once those are ship-shape, we can help you with your TA.

 

[chem geek]

As was noted, Trichlor is acidic so it is normal when using it that the pH tends to drop as does the TA. Usually with Trichlor people use pH Up product (sodium carbonate) that raises both pH and TA. By using baking soda, the TA rises more so can get too high. If the water had even a normal CH level, the TA could get high enough to have scaling.

In your Dallas pool, did you have sources of aeration such as spillovers, waterfalls, fountains, etc.? If these are not present in your Little Rock pool then that could explain the difference you are seeing. Also, was your Dallas pool newly plastered? That also can have the pH rise from plaster curing though that should significantly settle down after a few months and after the first year.

 

[WalterE]

Well, I have taken advice from the knowledgeable folks that have answered this thread. I have:
1. Switched to bleach as the primary sanitizing agent.
2. Turned the return jets toward the sky for aeration and running the pump 24 hours.
It's looking good. After a couple of days:

The PH has gone up from 7.0 to 7.2.
The TA has dropped from 150 to 130.

Waiting for my new Taylor K-2006 test kit to arrive -
I will publish my new more accurate readings when it comes in. Especially CYA.

One follow up question. Does one continue to shock on a regular basis? If so, how? More bleach?

Thanks for all your help.

 

[DaninFLA]

Well, I have taken advice from the knowledgeable folks that have answered this thread. I have:
1. Switched to bleach as the primary sanitizing agent.
2. Turned the return jets toward the sky for aeration and running the pump 24 hours.
It's looking good. After a couple of days:

The PH has gone up from 7.0 to 7.2.
The TA has dropped from 150 to 130.

Waiting for my new Taylor K-2006 test kit to arrive -
I will publish my new more accurate readings when it comes in. Especially CYA.

One follow up question. Does one continue to shock on a regular basis? If so, how? More bleach?

Thanks for all your help.

no, we never SHOCK. the principle we use here is to 1) start with a pool with no algae - if algae is present we SLAM, which is not shocking. then 2) we maintain our chlorine levels based on our CYA levels. as long as you keep your chlorine levels above the minimum at all times, you are not allowing new algae to form in your pool and there is never a need to shock. simple, huh? and easy!

however, based on your heavy use of pucks and shock, im guessing your CYA is going to be very high and a partial drain and refill will be needed before you start. but htat should be a one time thing as long as you don't go back to pucks and powdered shock. CYA doesn't get used up, so the only way to lower it is to drain the water and refill with fresh water

 

[Agent99]

But the 'S' in SLAM stands for shock. I understand the SLAMing process but there must be some subtlety I'm missing here.

 

[JVTrain]

Shock Level is the key phrase. You're achieving the desired FC concentration to eliminate algae = shock level. Sort of like turning the volume up loud enough to hear and leaving it there.

EDIT:

Put it all together and SLAM translates into: Bring FC up to the Shock Level concentration required to quickly kill algae, based on CYA level, And Maintain that level until all algae has been confirmed eliminated.

 

[pooldv]

Right, the pool store version of shock the pool is get a bag or bottle of something that says shock on it and throw it in the pool. Usually it is 1lb of dichlor or trichlor granules.

 

[DaninFLA]

But the 'S' in SLAM stands for shock. I understand the SLAMing process but there must be some subtlety I'm missing here.

that's not what the OP was asking. he is doing the pool store version right now where you use pucks and then once a week add a bag of shock and he was asking if continue to shock. the answer is NO. once you have an algae free pool, we maintain our FC levels and do not have to shock, SLAM, etc again. I detailed all that in my response

 

[WalterE]

OK. My Taylor K-2006 has arrived and I am in the process of converting to the BBB (With your help of course).
The pucks are out of the pool and the store shock is all locked up. Pool is currently clear and looks pretty good.
I'm only using the jugs of bleach and aerating using jets to raise PH (with some success). No other chemicals at this time.
It's taking 1 gallon (121 fluid ounces) of bleach per day to maintain free chlorine of 2-4 (is this unusual?).
Here are my new numbers from the Taylor K-2006.
FC 2.0
CC 0.5
PH 7.4
TA 150
CH 70
CYA well over 100 (note: on Taylor it's half way between the 100 mark and the bottom of the tube)

What's next gang? I'm in your hands.

 

[DaninFLA]

how much longer are you planning on having the pool open, that's my first question? the biggest problem you have is that your CYA is sky high and has to be reduced. if you are going to have the pool open for another month, I would suggest doing a 50% water change right away and then retest your CYA to see where you are at. with a CYA that high, your FC needs to be really high. for a CYA of 100, your MINIMUM FC is 7ppm. but you need to figure out your CYA. dilute your pool water 50/50 with tap water and re-do the CYA test. if your CYA comes out at 70, then its 140. if its over 100, you don't need to retest again (would be over 200).

my advice would depend on how much longer you plan on using the pool.

 

[WalterE]

I don't close my pool. I leave it open during the winter.

 

[DaninFLA]

ok, in that case, I would get started on drain/refill. target 50% if you can. with a vinyl liner, you don't want to go any lower than 1 above the shallow end. you gotta get your CYA under control so you can keep your pool chlorinated at a decent level. if you do not have any algae, and no need to SLAM, maybe get your CYA down to 60-70 for now, and then you can try and get it lower with subsequent small changes over time.

 

[WalterE]

Draining the pool. My shallow end is 3 feet deep. It appears that if I take the water level down 2 feet, I will take out 10,600 gallons or about 42.4% of the 25,000. Looks like I would have to take it to 6 inches in the shallow end to get 50%.

Draining technique - I assume I would close off the skimmer to take water only from the bottom drain and put the filter on waste. I really don't want to damage my liner.

And then re-test the CYA.

Any other words of wisdom?