Controlling PH upwards creep with balanced chemicals

[blairsooley]

Seems to be a common topic but thought I'd ask for a bit of quick advice on keeping PH stable as it typically rises about .3 per day. As a result, I'm adding Muratic every two days to bring it back down from 7.8 to 7.2. The pool water is beautifully clear now. I recently battled a bad case of the algae's by bringing TA from 60 up to 110 and bringing FC from 3 up to 4-5 to battle the intense TX heat. I have a water feature that runs about 30 min per day and a spillway from the spa to the pool that runs about 8 hrs per day.

My TF100 tells me the following:
FC - 4 to 5
CC - 0
TA - 110
CYA - 35
PH - 7.5 (at the moment)
CH - 275

Thanks in advance for the advice!

 

[Akathisia]

You can slow your pH rise by lowering your TA but you don't have to. Adding MA to lower pH is pretty standard.

Also, aim for a higher pH and you'll be happier. 7.2-7.8 is a range. 7.2 is not a necessary goal.

See this thread TA for a typical discussion or search for more on TFP

Here's how to lower TA Pool School - Lower Total Alkalinity

 

[blairsooley]

Thanks Akathisia. I've been aiming for 7.5 as a median PH goal, but try to get it to 7.2 to give me two days before I have to add more Muratic acid addition rather than adding it everyday. Hopefully, it will eventually reach the TA/PH equilibrium point mentioned in the Pool School link you mentioned. I have tried the TA lowering process a few months ago using my spa blower and that worked very well, but I'd like to see if the equilibrium happens first so I don't lower the TA too much manually.

Also, I see in that the TA forum link that it notes a PH of 7.8 is ok for TX, where I'm located. Isn't a low PH better for the FC to kill algae?

 

[Catanzaro]

I recently battled a bad case of the algae's by bringing TA from 60 up to 110 and bringing FC from 3 up to 4-5 to battle the intense TX heat.

Welcome to TFP and please add your signature. We need to have details on your pool. You can look at mine as a reference. Also, the issue here is that you raise your TA from 60 to 110 to battle algae. This is one of the reasons why you have rising PH issues. I was at 130 and now mine stays between 70-80 max, which stabilized by PH problem. You did not have to raise your TA that high.

Now, with the spillover spa and water feature and high TA, you will be battling the rising PH for a while until you get the TA back down. Each pool is different and you will find what works over time. It is recommended that you do not use aeration devices in your pool as this will create a faster rise in PH. Unless you want to lower TA quickly, etc.

- - - Updated - - -

Isn't a low PH better for the FC to kill algae?

Lowering your PH to 7.2 is recommended during a SLAM as liquid chlorine will raise PH. As the chlorine burns off, the PH drops back down to the normal starting point.

 

[mknauss]

Isn't a low PH better for the FC to kill algae?

Some light reading -- Pool Water Chemistry

The second major discussion in the thread is about the effect of pH on the active chlorine in your pool. With a CYA of 30 or higher, there is minimal difference in the effectiveness of chlorine at a pH of 7.8 versus 7.2

Liquid chlorine is pH neutral (it itself is high pH, but when it oxidizes its effect is neutral to the pool water). Your pH rise during a SLAM is due to your normal pH rise from water additions or aeration. Primarily due to elevated TA.

Take care.

 

[blairsooley]

Great information, everyone. It sounds like I should drop my TA a bit manually and sounds like leaving my PH near 7.8 won't hurt my chlorine's effectiveness. I was going by typical TA recommendations of between 100 and 120 but that sounds like more or a high end from the various conversations I've been reading on this forum.

 

[blairsooley]

Things straightened out themselves at PH of 7.5 and a TA of 80. Thanks all.