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All other parameters are within normal limits. pH is low at 6.8 - has been running 7.2 for 6 weeks.
When I do the Alk test - 2drops #1 - swirl - then 5drops #2 - INSTANT RED.
What do I need to do??? I'm thinking 2 cups baking soda - test again (how long should I wait) and then go from there. Am I on the right track?
Pool water looks great - eyes did burn some when I swam on Sunday.
You pH is probably a lot lower than 6.8. That is the lowest that phenol red can test. I would start putting in borax to get your pH up to at least 7.4 and then retest your TA. If the TA test is turning red immedaitely it means 0 ppm TA and that is probably because of a very low pH.
I'm off to get some borax (I know - I should have had some on hand BUT I've never had this problem before) - any thoughts on what could have caused this?? Just curious AND interested to know if it's something I could (should) have addressed earlier. I don't always test the TA - maybe once a month - because it's never been a problem before. pH has generally been steady at 7.2 to 7.4. Robin
If you started with some amount of TA, then a combination of acid addition and aeration would cause the TA to go away. Were you using Trichlor tabs/pucks as your source of chlorine and if so were you using only Borax to raise the pH? If so, then that might explain what happened. When using Trichlor (or any acidic source of chlorine including Dichlor) you should use pH Up / Arm & Hammer Super Washing Soda / Sodium Carbonate as your base to raise pH. This will add carbonates back to the water. When using Trichlor you want the TA to be higher (usually at least 120 ppm) because you need more pH buffering and can achieve a sort of balance between Trichlor acid, carbon dioxide outgassing and sodium carbonate addition.
If you have been using Trichlor, then you should check your Cyanuric Acid (CYA) level as it could be high.
If you haven't been using Trichlor and were using bleach or chlorinating liquid or even Cal-Hypo instead, then were you seeing a frequent rise in pH and adding lots of acid frequently to compensate and keep the pH lower? If so, what was your pH target?
Also, do you have a waterfall, spillover, vanishing edge, fountain, shower or other aeration water feature?
Richard
I have been using Trichlor - it's usually around this time of year when I switch to bleach - I add some CYA in the spring and then use the Trichlor until my level gets to 100 - which is what it's at now. I have not been using anything else - never had this happen all last year.
I could not find any borax yesterday so I added 3# of baking soda - I did not have time to test the TA before work this a.m. but I tested the pH and it's "lower" - as in it tests as yellow as the chlorine - at least yesterday it was a little "pink".
I'll have borax to put in this evening BUT is there something else going on here?? Is it okay to swim?? REALLY - I have not put anything else in the pool and the trichlor is the same as what I used early in the season last year - Lowe's brand. WE have had some significant rain the last 7-10 days - probably 1 1/2" and it's been so dry that up until this past week all water added was municial water that tests generally around 7.2-7.6.
Rain is a great aerator so in combination with the acidic Trichlor will lower the TA. At any rate, it's important to get the pH up AND some TA in your water so the easiest way to do that is with sodium carbonate which is in pH Up products but is also in Arm & Hammer Super Washing Soda.
Richard