AG auto. Chlorine feeder

[SCpool]

I did want a book! This has all been SO helpful!! I know exactly where I need to start and the course I am going to maintain. And conveniently, I am physics teacher and can totally calculate the flow rate turnover in my pool! YES!!

One last question: what do you use to clean your sand filter and how often do you clean it? How often do you replace it? I think the filter is working fine, but it could be what I am just used to, you know what I mean? When the PSI goes up, I backwash and I know what my clean pressure hovers around, but wondering if a clean pressure of about 19 PSI is normal.

[aylad]

Clean pressure is different for different filters. Contrary to popular belief, you should never have to replace the sand unless you really get it gunked up (Baquacil conversion, overkill on suntan lotions and oils, etc.). One or more of our mods is going over 10 years with the same sand! You don't really need to use anything to clean the filter, except backwashings when the pressure indicates. You need to backwash when the pressure rises 6-8 psi over your "clean" pressure. As long as it's doing an effective job of keeping your water clean, then you're good!

I do agree with Anna that you can cut your pump run time from 24 hours to something shorter. In my pool, 6 hours or so daily (26K gallons, 300# sand filter) works, but to make it easy during the summer I just turn it on when I get up in the morning and turn it off sometime after dinner

[PoolDoc]

And conveniently, I am physics teacher and can totally calculate the flow rate turnover in my pool! YES!!

Sorry to pounce on your thread, but I saw your note. High school or college? I'm looking for someone who can do differential error analysis of pool test & dosing activities -- I'm really tired of various resources that instruct people to add "6.17 lbs of Alkalinity increaser to increase their Total alkalinity by 23 ppm".

I know this sort of instruction is stupid, but I need a big scientific hammer to SQUASH it with. End-to-end DEA of the testing and dosing process IS that sort of hammer, but unfortunately, I lost the ability to do DEA 28 years ago (about 6 months after I learned how!).

[SCpool]

Hi PoolDoc,
High school, it used to be in my realm to do that when I was in grad school, but those days are long gone for me too. AP Physics no prob, but DiffyQ would take a hefty amount of re-studying on my part.

Thanks Aylad about the sand filter advice, it actually runs just fine, I only became concerned when other people told me that I "needed" to replace the sand. Thanks again! I'm going to print this entire thread!

[AnnaK]

One last question: what do you use to clean your sand filter and how often do you clean it? How often do you replace it? I think the filter is working fine, but it could be what I am just used to, you know what I mean? When the PSI goes up, I backwash and I know what my clean pressure hovers around, but wondering if a clean pressure of about 19 PSI is normal.

The sand in my filter is 7 years old. I've never replaced it. My clean pressure is 12 PSI and I backwash/rinse when it gets to 18 PSI. I backwash/rinse at the end of the season before I drain the filter. After the equipment is hooked up again in the spring and the filter is full and functioning I put it through a 30 second backwash/rinse cycle to sort of fluff up the sand. Don't know if that's necessary though. I just checked my log book: Last season I backwashed 3 times, so that's about every six weeks during the swim season.

Something that really helps keep your filter cleaner are skimmer socks. I buy mine at the pool store. They look like white knee-hi ladies' hose. You put them inside the skimmer basket and fold them over the edge of it and they act like a coffee filter of sorts. They'll catch pollens (which will look like yellowish gunky stuff similar to drywall mud), tree bracts and flowers, algae, small bugs and etc. I generally check the skimmer sock a couple times each day. They can get very dirty and can impede flow. Rinse it out under running water and put it back in. Be sure it's inside the basket, you do not want it to get sucked into the pump pot! Here, they cost about $7 for five and five will last me two seasons.

Some pool owners use regular pantyhose which can be cheaper than commercial skimmer socks. I've never tried it.

So do tell, how do you calculate turn-over?

[aylad]

I second Anna's suggestion to use the skimmer socks--they're well worth the investment and you'll be AMAZED at how much junk they catch before it gets sucked into the filter, thus decreasing the frequency that you'll have to backwash.

Janet