Latest Numbers - Low TA

[usdave1t]

So just wanted to check in with my latest test numbers and query whether low TA is a problem?

Results from this morning as follows:
pH 7.5
FC 10.0
CC 0.0
CH 325
TA 70
CYA 60

I have been adding 1 to 1-1/2 pints of acid every other day to keep pH down, it is tending to drift up about 0.1 a day. Also added approx 12lb Calcium plus just over a week ago to bring the CH up as it was previously down at 250 which I thought a bit low.

According to the instructions with the TF-100 kit the TA should be 100 to 120 so wondering if mine is going to cause any issue and should I take any corrective action.

Also I am manually chlorinating with bleach. Looks like i over did it last night as my target FC is 7.0. Will just let that drift down on its own.

However, putting all the above into pool math my CSI is -0.11 which indicates everything is good??

Thoughts / advice appreciated

Thanks
Dave

 

[Jezza]

You'll find that your right on the lower recommended level for TA although if it goes a lot lower you will find that your pH may become unstable. See Recommended Levels

How often are you running your spa/spillway as this would be creating some aeration which will be raising your pH.

Are you finding that your pH is stabilising with the lower TA?

 

[usdave1t]

You'll find that your right on the lower recommended level for TA although if it goes a lot lower you will find that your pH may become unstable. See Recommended Levels

How often are you running your spa/spillway as this would be creating some aeration which will be raising your pH.

Are you finding that your pH is stabilising with the lower TA?

Thanks for the reply

What would have caused the TA to drop? It was consistently at 80 for the last couple months and just now dropped to 70 this week. Only thing I have added other than acid was the calcium plus to bring the CH up.

pH is consistently going up by about 0.1 each day. I hadn't thought about the aeration from the spa spillway. With the pool pump running it circulates through the spa too. I am running my pump 12 hours a day - maybe I don't need to run it that long?

Dave

 

[Jezza]

The TA is dropping because of the acid you are adding. While it lowers ph it is also lowering your TA. So with the time you are running your pump and the subsequent aeration being created by the spa/spillway your sort of in a cycle with a net loss of TA.
As mentioned earlier it's not a problem at the moment but if you start dropping to 60, then you'll need to add baking soda to bring it back up. Reducing your pump time will certainly help. In fact you might be able to get it down to 4 hours run time.
Check this out Determine Pump Run Time

 

[usdave1t]

Thanks Jezza, makes sense. I will try dropping my pump run time down and of course keep an eye on the TA to ensure it doesn't get too low

Appreciate the help
Dave


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