DE filter pressure increases when adding pH Rise

[Bill_in_Marriottsville]

Greetings

With all the rain in Maryland this summer I've had to work to keep my pH up in the pool. I've used pH Rise (from HTH) to accomplish this, broadcasting to the surface of the pool per the instructions. While it does raise the pH, the pressure of my DE filter jumps up from about 20 psi to 30 psi within an hour or so of application, and remains there until I backwash the filter. This is very annoying as I sometimes need to add the pH rise a few times a month--I feel like I'm wasting a lot of DE.

Any thoughts as to what's going on here? I don't have this problem with any other chemical/additive.

BTW, recently I tried dissolving the pH Rise in a bucket and tossing the water in the pool, thinking maybe it wasn't dissolving quickly enough for the filter. No change, the pressure went right back up.

Many thanks in advance

Bill

 

[JVTrain]

How are you chlorinating the pool?

Can you post a full set of test results?

pH
FC
CC
CYA
TA
CH

Borax (20 Mule Team) is generally recommended for increasing pH here at TFP but further advice needs to be based on your test results.

 

[Bill_in_Marriottsville]

Thanks JVTrain. I've got a chlorinator (guess I should've mentioned that in my sig file), and sometimes toss in the floating canister with the chlorine tablets inside. I'll try to get some new test results tonight and will post them.

 

[JVTrain]

Without test results, I can tell you that trichlor tablets (those used in chlorinators and floaters) are acidic. They will lower your pH and your TA over time. Your pH will bounce back up, provided your TA isn't too low but your TA will only go down, unless baking soda is added to the pool. When your TA gets low, then your pH will bounce around and can drop quickly. There are some tablets that incorporate baking soda (sodium bicarbonate) into the pressed tablet to attempt to combat this TA/pH decrease due to tablet use. However, trichlor tablets are also constantly raising your CYA (stabilizer) which is bad for your pool sanitation in the long run as well.

Test results from the pool store are largely ignored here on TFP because they are usually inaccurate and come bundled with terrible pool store advice. The only test results that matter are those you test yourself with a recommended test kit. The TF-100 from tftestkits.net or the Taylor K-2006 have all the tests you need.

 

[Bill_in_Marriottsville]

Without test results, I can tell you that trichlor tablets (those used in chlorinators and floaters) are acidic. They will lower your pH and your TA over time. Your pH will bounce back up, provided your TA isn't too low but your TA will only go down, unless baking soda is added to the pool. When your TA gets low, then your pH will bounce around and can drop quickly. There are some tablets that incorporate baking soda (sodium bicarbonate) into the pressed tablet to attempt to combat this TA/pH decrease due to tablet use. However, trichlor tablets are also constantly raising your CYA (stabilizer) which is bad for your pool sanitation in the long run as well.

Test results from the pool store are largely ignored here on TFP because they are usually inaccurate and come bundled with terrible pool store advice. The only test results that matter are those you test yourself with a recommended test kit. The TF-100 from tftestkits.net or the Taylor K-2006 have all the tests you need.

Yeah, I'm with you on all the chemistry--but my real problem is why I need to backwash my filter every time I raise the pH. I'm in decent shape with the chemistry side, I just don't want to keep blowing through DE at this record pace.

 

[JamesW]

I would avoid pH increaser. If you use baking soda, the pH will be good.

If the pH keeps going too high, the TA is too high. If the pH keeps going too low, the TA is too low. When the TA is right, the pH will be stable.

Try adding 0.5 lb baking soda per tab used to maintain a consistent TA.

For example, if you put 4 tabs in the feeder, add 2 lbs bicarb to the pool and brush.