Slamming for 32 days

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E

EnormCrane

Member
Mar 29, 2019
16
Modesto
Pool Size
30000
Surface
Plaster
Chlorine
Liquid Chlorine
Let my pool go. Bringing it back but the SLAM process that has worked for me in the past is proving to either take longer or I have a filter issue.

Switched to Sand filter in the Summer, so filter and sand are about 6 months old. Pool went to blue cloudy after a few days, but it’s still cloudy and I’m still brushing dirt every day, sometimes twice a day.

CYA was low when I started, and it’s the only test I got from the pool store, but I figured we don’t get much sun and the lower cya would make maintaining SLAM levels easier.

Also, I set up my signature, but am not sure what will post, so here’s pool info.

30,000 gallons
Pressure side Polaris P39
Jandy SFTM 24-2.0 Sand Filter (current pressure 10psi)
Century Centurion Main (1hp) and booster (.75hp) pumps

I think my logs on Pool Math are public, but I’ve been religiously following TFP methods with 100% success rate.

Here’s the question: with CC at .2, passing OCLT, and water that is just cloudy, do I just keep up on the slam until water is clear (I know the answer, I just need some encouragement)? The reason I think maybe not is, I haven’t tried any filter additives like DE or other branded filter aids. Should I try that? I was backwashing every couple days at first, but filter pressure hasn’t risen to 25% higher than baseline in a couple weeks. I just backwashed and rinsed today, but I was trying to hold off because I know that a slightly dirty filter cleans better.

Cloudiness shown in these photos is right after brushing. When the dirt settles, the water is clearer, but not perfectly crystal like normal. Is it just dirt at this point that my filter needs time to catch? If so, can I let FC levels fall back to normal and resume balancing the rest of my water chemistry?

Thanks, guys!
 

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Your pool is clear enough. Not perfectly TFP clear but clear enough to pass the SLAM process.

If you pass the OCLT and your CC's are below 1 then you can resume normal chlorination.

I would keep your FC 1-2ppm on the high side of your target.

You can then work in improving your filtering with a bit of pool grade DE.

Sand Filter Use and Care - Further Reading

www.troublefreepool.com www.troublefreepool.com
 
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Your last CYA test was some time ago and measured at 11ppm? How was this tested? Additionally, what FC level are you aiming for while testing as your FC level seemed to be low for a slam most the time?
 
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Leebo said:
Your last CYA test was some time ago and measured at 11ppm? How was this tested? Additionally, what FC level are you aiming for while testing as your FC level seemed to be low for a slam most the time?
Click to expand...
Measured at pool store because it was reading lower than 30. But that’s the only test from the pool store and I figured since sun isn’t much of an issue for my pool this month, I’d be ok. Haven’t been regularly testing anything but FC/CC since slam started, which is why CYA test is a month old.

I was shooting for 10 ppm as per pool math. Chlorine loss just recently slowed down. It was faster until a few days ago, which is why tests are lower than 10.

Do you think I need to keep SLAMing?
 
Without cya you are also fighting with the sun and this will consume alot more fc making it hard to maintain slam level.
Get the cya to 30. I would add 10 or 15ppm worth via the sock method and retest in 24hrs.
 
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Second update: brushed this morning. Waited about an hour. Logged filter pressure at 10psi. Added 1/4 cup DE powder dissolved in a gallon of water via skimmer. Pressure went up to 11psi in 2 minutes, and is now at 15psi about 20 minutes after adding. If it gets to 20, I’m going to backwash again. Weird that just 1/4 cup would do that much, right? The info on adding DE said it typically takes 1-2 cups just to raise pressure by 1psi. Also, I just swapped the pressure gauge a couple weeks ago, so I know it’s functioning.
 
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EnormCrane said:
Weird that just 1/4 cup would do that much,
Click to expand...
So as any filter gets dirty, the crud filters even finer crud making the filter more efficient. (Until the flow is restricted at least). By adding DE to a sand filter you're basically jump starting by starting with a 'dirty filter'.

The amount of crud needing removing decides the rest, for example how much you needed to add and how quickly you need to backwash. For larger jobs such as an active or recently active algae bloom, it won't take much or long to do its thing.

Seeing how under normal circumstances, your yard crud is a constant no matter which filter you use, it is my opinion that your yard decides how finely you filter. The only question is how long does the sand filter take to catch up when it's freshly cleaned.

Stay the course, repeat as necessary. You're cooking with gas now. :)
 
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Exactly that !! You add DE and speed up the water being polished. Then you backwash it out along with the crud it trapped. Repeat until it sparkles so long as you can keep an eye on the quick PSI rise. (y)
 
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Don’t sweat the amount.
Every pool is different with how much it takes - I use about 1 cup with a 300# sand filter (with a crystal clear pool).
Some folks need multiple cups.
Your box of de might last you forever ♾️ at your rate of use 🤣 - not a bad thing!
If you have to be away & can’t babysit just omit the de & resume when you’ll be around to check psi & backwash when needed.
 
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Ok. Now that I am fully on the right track and know how to use DE in my sand filter, I feel like I’m back into the swing of maintaining my pool. Switching from cartridges to sand this summer has been a real learning curve, but I was just telling my wife that this group of folks has some of the best people around. Y’all have been quick to respond every time I’ve had a question and very knowledgable. When I got this house in 2019, I knew I wanted to maintain my own pool, and it is this website, protocol, and group of folks that have helped keep my pool crystal clear. Thanks, folks. I appreciate you.
 
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Great. Be sure to update your signature. It still shows a cartridge filter.
Interesting you switched to a sand filter. Most are switching to a cartridge filter.

Take care.
 
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mknauss said:
Great. Be sure to update your signature. It still shows a cartridge filter.
Interesting you switched to a sand filter. Most are switching to a cartridge filter.

Take care.
Click to expand...
I switched to sand on a recommendation from a friend who runs a pool service. I’m good at chemistry and cleaning, but maintaining my filters and other equipment is proving to be my weakest point. I also live in a very agricultural town with lots of harvest dust and the like. He said that, since I am not great at keeping cartridges clean, he would recommend switching to sand. I know cartridges filter down to smaller particles, but my dirty filters probably weren’t working as well as my sand filter is. So far, my water has been cleaner. Maybe when it comes time to update, if I have more time to maintain equipment, I’ll switch back. But for now, I think sand is best for me. All this to say, I hope I didn’t make a mistake!
 
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