Pentair cartridge filter rusting inside

[sdv]

Hello, I have some issues with rust inside my cartridge filter. See pictures.

Some background:
Pool is about 3 years old. Located in a Houston suburb
SWG
~25,000 gallons
Using BBB from the beginning. Never had an algae [emoji3]

Here are my typical chemistry ranges:
PH is 7.6 - 8.0+
I am out of town during the week, so typically all maintenance is happening on weekend. Typically I add 1/2 to 1 gallon of acid every week. PH is back in 8.0 range every week

TA 40-70
When TA gets down to 40 I typically bump it up with baking soda

Salt 2950-3300
Salt level varies depending on the amount of rain we get. Typically when it drops below 3000 I add 2-3 50lb bags of salt

CH 290-330
Gets lower with rain but then trending higher with fill water

I wonder if these swings in PH (due to weekly maintenance cycle) can cause such rusting. I wonder if I need to get an acid feeder.
I have noticed rust about a year ago. It is getting worse.

Any thoughts? Suggestions?

 

[JoyfulNoise]

Bar Keepers Friend works great at removing rust stains.

It contains oxalic acid so you MUST rinse out the filter really well after use.

Sent from my iPhone using Tapatalk

 

[cowboycasey]

I dont think it has anything to do with a high PH, maybe a low PH would but you say it always raises.. It probably has more to do with the salt water than anything.. with a SWG pool this is what happens, it will take life of the motor, filter or anything else that has metal... how much life is hard to know.. that filter may last the next 15 years, there is no real way to know for sure...

 

[sdv]

Thank you for your input. I will try to clean it with Bar Keepers Friend.
My bigger worry in not the life of equipment but rather iron stains in the pool.

I wonder if rusting of the equipment is common with SWG or if I have messed up something.

 

[pabeader]

I will have to take another look at mine. I have the same model, and a SWG. I think I remember seeing rust in the same places. I just assumed it was from all the metals I have in my water. Will report in the morning if I get a chance to look before work.

 

[PoolFlunkie]

I opened my Pentair filter after a year in service and it looked very similar. I also have a SWCG and have trouble controlling the pH (it goes high). I have an acid addition system but can't get enough acid added to maintain pH below 8.0 without manual acid addition. With all that said, I think it's just cheap Pentair parts. The band is stainless steel so I wouldn't expect to see rust regardless of the pH or salt content. I'm not sure how the band is fastened to the fiberglass container but there's obviously some non-stainless steel parts metal behind the band that are rusting that would be worse with salt and pH excursions...