Super low alkalinity

Rangeball

Well-known member
May 25, 2007
785
#1
My dad said his PH was real low and asked what to do about it. I asked what his alk was, but he only has a really old HTH test kit for CL and PH. I tested it with my 6 way HTH kit and indeed his PH registers below 6.8, color definitely out of range. I then checked Alk, and the reagents are supposed to change from green to red when titrated, however, the green drops turn red without adding any of the second reagent. At first I thought I'd used the wrong drops, but nope. Checked the drops in municipal water and the are indeed green. Assume this means his alk is super low.

I added borax but this was before I knew the alk was so low and ph didn't budge. I'm making the assumption based on the Alk test that his alk is 0 (can't be though, right) and targeting 80 ppm will add the appropriate amount of baking soda this afternoon. Will let circulate and retest in a few hours (small pool with overpowered pump, lots of circulation).

Am I on the right track? I've never seen Alk or PH this low. He uses the people that installed his pool to open and close as well as trichlor pucks in an inline feeder. I had thought they might be the problem and still might be. I tried to get him to BBB but he's too lazy to buy bleach and manually add it. He also uses bag shock, I'm assuming dichlor so should have a small impact on PH, but I'll check. It's early in the season but I'm sure his CYA is already high, but I can't find my reagent to test, will require a more in depth search.

He has a heater. With PH this low, I told him to be on the lookout for green hair :(
 

Bama Rambler

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2009
22,894
SouthWest Alabama
#2
If it immediately turned red it means the TA is zero (or very close) and his pH is about 4.5 or so. You need to get the TA up as quickly as you can. Then retest and adjust the pH.
 

Rangeball

Well-known member
May 25, 2007
785
#3
Thanks. I'm entirely perplexed as to why his alk is that low. This is his 3rd or 4th year with the pool. Never a problem before now. Which is why I wasn't really worried about not having an alk reading before adding the borax.

What's the chance the borax we added will still have an affect on PH once we bring alk up?
 

Butterfly

TFP Expert
LifeTime Supporter
May 30, 2007
10,045
South Carolina
#6
One of the 'side effects' of trichlor's acidic nature is the pH and TA will crash if not monitored closely. Sounds like this is what happened. Also, we recommend a higher TA level for trichlor users. TA should be 100 - 120 and be sure it doesn't fall below 100.
 

Rangeball

Well-known member
May 25, 2007
785
#7
Thanks. I've personally been off trichlor for so long I hadn't paid any attention. I've added enough baking soda to bring it to 80 if it was 0, pool only takes 3 hours to turn over so will check it again this evening and go from there.

He doesn't monitor anything. Water was clear, I'm suprised he even checked as that's usually the only way he tests it. This time it was prompted by eye burning and skin irritation of my nephews recent swimming.

I think I need to get him to spring for the TF test kit and tell him I'll do all his testing if I can keep it at my house :)
 

Rangeball

Well-known member
May 25, 2007
785
#8
Now I'm wondering. I worked hard to get my alk down in my BBB pool and it goes against my will, but given that he is not likely to suddenly see the light and at least test weekly, I'm wondering if I should shoot his alk to 180 or so to give him a larger buffer to protect against the trichlor use. Looking at the pool calculator, he's using roughly 10 80z pucks weekly, which put's about 50ppm chlorine and can lower PH by 2.7. That may at least give PH a fighting chance at stabilizing?

Oh and about 30 ppm CYA weekly as well. I'm expecting an algae crisis this month. I need to calculate his actual needed puck use and get him to change. Right now he just fills the hopper once a week and lets it go. And he is shocking with dichlor. I asked him why then told him to stop.

The HTH OTO didn't register any chlorine and when I checked his hopper it was empty. Now looking at how much he's been using I'm wondering if his chlorine is really sky high and bleaching the test out, but OTO should still just turn dark orange, right? I need to test it again with my FAS-DPD kit.
 

JasonLion

TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
37,879
Silver Spring, MD
#9
As long as there isn't a fountain, waterfall, spa, or other water feature, you can raise TA as high as 180. If they really never test that will only be a stopgap, but it is better than doing nothing.
 

Rangeball

Well-known member
May 25, 2007
785
#10
Nothing like that, just kids jumping in. I had his pool perfect and trouble free. He just had to buy bleach and add it daily. He got lazy and took the easy way out not realizing it's not really easy, just different issues which are more of a pain to deal with. Maybe this will help him see the light.
 

Rangeball

Well-known member
May 25, 2007
785
#11
Got alk up but PH still registering low (around 6.8). Have added borax but doesn't seem to be doing it. Before I add more, can high CL mess up the PH test? He's been circulating his pool 24hrs instead of the normal 6 to mix everything we've been adding and his CL is now orange with OTO, so I know it's high. Will test again soon and if still high, will close the chlorinator until it drops down to yellow again.
 

JasonLion

TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
37,879
Silver Spring, MD
#12
High FC levels tend to cause the PH test to read higher than actual. Extremely high FC levels, think 20+, will turn the PH test a purple color that most people interpret as 8.2, but some see as 6.8, and which really isn't either one. If FC was that high the OTO test would be brown, so that probably isn't an issue here.
 

Rangeball

Well-known member
May 25, 2007
785
#13
Thanks. By the time I got by to test CL had dropped well into OTO range, PH is now definitely 6.8. Will be adding borax this afternoon.