DE in sand filter?

[sloop]

Hi, I am new to the forum. Thankyou for letting me join. I have an AG 15x30 with a dish bowl 6' deep end. Approximately 12,000 gals. I think. A 1 1/2 HP pump with a 17" diameter filter. It holds 150 lbs. sand. I know it's to small for my pump or vice versa. I can only put 1 1/2 oz. DE in my filter. More than that the pressure raises more than 1lb. I've read where others put in a cup or two. Does mine do that cause the filter is so small? Can I put in more without it hurting my pump or filter? Also I didn't want to wait to try the socks in the skimmer so I cut some cloth from a T shirt and put it in the skimmer with a thick rubber band. It works very good. That didn't effect the pressure at all. I tried the DE before I put the cloth in the skimmer. I was a little worried bout putting the DE in the filter so decided to put it in the skimmer with the cloth. That works good to. But it doesn't take much and if I put to much in the skimmer my pressure drops. Will that hurt the pump? Is it O.K. to let the pressure drop a pound or two? I don't know how many people have experience with putting DE in a sand filter but I'm sure there's alot out there that know more about pumps and filters than I do. I know zilch. This is such an awesome site with lots of good tips and tricks. Thankyou.

[CarlD]

Being cautious is very wise. Actually, you are on the right track. The measure of enough when adding DE to a sand filter is when the pressure goes up about a pound--however much DE it takes. If your filter only takes 1/3 of a cup to do that, so much the better! Your 10lb box of DE will last a lot longer!

"Skimmer Sock" is a brand name that we all use, like saying "Band-Aid" rather than "Adhesive elastic bandage". Most pool stores I see have them under some name or another, usually at or near the checkout.

You can also try a piece of stocking, too.

[Poconos]

Carl is right on. Your pressure drop when you add before your 'sock' in the skimmer indicates you're blocking the suction. I'd add the DE, let it get trapped in the filter, then put on the sock. The 1-2 cups I've mentioned in other posts is for my 300# sand filter. Can't emphasize enough to go slow at first and wait maybe 20 minutes to see where the pressure stabilizes before adding more DE. For some reason it takes a while to stabilize after adding. Probably as the DE works into the nooks and crannies of the sand. And yes, your pump is way too big for that filter. The good thing is if DE isn't getting blown back into the pool and the pressure stays up, it indicates the high pump flow is not causing channeling in the filter. That's where high flow will basically cut bypass channels in the sane, negating filtering.
Al
BTW: Welcome to the forum.

[sloop]

O.k. so it's better to add the DE to the filter than in the skimmer with the sock. Thankyou. I am really disappointed I was sold a small filter with a 1 1/2 HP pump. This is my second summer with this pool. And couldn't clear my water this secound summer so I drained and refilled. I'm thinking it's cause of this combination. Does the DE slow down the flow in the sand? Can I get by with using the DE with this combination? I'm thinking not. Or in your opinion should I get a bigger filter or smaller pump with this size pool? I got this info. off the filter-Max. Pressure Drop 15.2 PSI-Rated Pressure 50 PSI-Rated Flow 60 GPM. And Flow Rate 30-40 gpm. Got this info. off pump-RPM-3450, HZ60. That's the only info. off pump I can understand that might be of some use. Do you think it's fair to ask the Co. I bought pool from to replace either or with a more proper size? Could the 1 1/2 HP pump be pushing the water through the sand so fast that's it's wearing out the sand that fast. You know like how streams will smooth out rocks from the water flowing over them. My brother told me to bump the sand but that didn't help clear the water. I know channeling is bad. If I take off the top to the filter can I see if the sand is channeling? I know it's alot of questions. But I do extremely appricate your opinions. Thankyou and tks for the welcome also! Oh by the way I had to buy a 25lb bag of DE cause that's all I seen in the pool section HD had. LOL.

[CarlD]

O.k. so it's better to add the DE to the filter than in the skimmer with the sock.

Huh? You MUST add the DE through the skimmer--you take out the sock first. You just want to add enough to raise pressure about a pound--1/4 to 1 full cup max, usually, whatever it takes.

[sloop]

Huh? You MUST add the DE through the skimmer--you take out the sock first.

That's what I meant, what you said. I just didn't word that right. Apoligize for that. Thanks.

[Poconos]

No matter how you cut it your pump is grossly oversized for the pool and filter. You;re wasting a lot of $$$ in electricity. I don't think the sand is getting beat up as that takes a long time. If you take the top off the filter you should see a coating of white DE on the top of the sand with no noticeable cracks. Or, let the pump run a bit before adding DE and when you do add the DE then have someone keep an eye on the return(s). If DE shoots out, your filter is channeling.
Al

[sloop]

No matter how you cut it your pump is grossly oversized for the pool and filter.
Al

Thankyou so much. I am going to look into getting a smaller pump. Since no mention was made about the filter except the pump is grossly oversized for it. I'm thinking it's big enough for my volume of water. I don't see DE shooting out and it holds the 1lb. pressure rise.

[Bleach=Chlorine?]

Sloop,
I have a 1 1/2 HP pump on for my IG pool. There is over 50 feet of lines running underground with the pump and filter above (elevation) the pool. Just a bit of over-kill for your setup :-D