Sand or Cartridge Filter for New Pool

Hi All,

We're about to sign on the dotted line for a new inground pool. The builder has offered a choice of either a sand or cartridge filter. In our first pool, we had a cartridge. Water was very clear but it was somewhat of a pain to clean.

Have never dealt with a sand filter. Anyone out there have experience with both? Is it true the water clarity isn't as good? I like the simplicity of sand but just not sure. Can anyone tell me about backwashing? How often you backwash and for how long? Is there sand "maintenance"? Replacement?

Thanks for any input. Can't wait for Spring!

I had a cart for 3 years in an Intex donut, then a sand filter in my current pool for the last 12 years.
Sand filters are probably the easiest filters to maintain.
First, your sand filter should have a noticeably greater capacity than the pump. I have a 200 lb sand filter and a 1HP Hayward SuperPump and the filter is barely adequate. A 250# filter would have been better. Luckily, I have a 2 speed version of the pump and it works better on low speed. (get a 2 speed or VS pump). The slower your flow rate, the better the filter works.
Second, TECHNICALLY, a sand filter doesn't have as fine a filtering as either DE or a cart filter. But that can easily and CHEAPLY compensated for by using skimmer socks and adding a little DE (like 1/3 cup) to your filter after you backwash. Less than $10 worth of DE powder has lasted me over 3 years now...and $10 of skimmer socks should see you through a season. Both help your sand filter do its job.
Third, you backwash when your pump pressure increases by about 5psi. If you pre-plumb it into a drain, you merely turn the pump off, swing the multi-valve lever to backwash and run it till the water in the sight glass runs clear. Then turn it back to filter. Simple. Usually takes less than 5 minutes every few weeks.
Fourth, unless you add something really bad to your pool (nothing WE would suggest), you NEVER have to change the sand in your filter. As the sand gets older and "dirtier", it actually filters BETTER than new sand. It's because the wear and the locked-in dirt REDUCES the size of the spaces in the sand, catching more stuff.

My water is crystal clear, and so is that of most of our sand filter owners. Old sand, DE, big enough filter for the pump, skimmer socks and you'll get GREAT performance!

I'm with CarlD on this - I love my sand filter. That said, there are fans of Carts and DE here as well. The most important thing is to size the filter to the pump - the next size bigger filter and the next size smaller pump than commonly suggested is a good start.

One thing to add to CarlD's post is a rinse between backwash and returning to filter will prevent a plume of dirty water returning to the pool.

Another vote for sand. Also one more tidbit ----- when you initially fill your filter with sand, do a quick backwash before putting it on filter.

Thanks CarlD. I don't think we'll be able to backwash to a drain but it's something I'll inquire about. That would be the best setup IMO. However, if I'm backwashing onto grass/shrubs or trees, will DE hurt them? I'm assuming some of it comes out during the backwashing.

Found the skimmer socks and they are pretty cheap as you mentioned. Does one size fit all baskets? How often do you change yours?

Thanks BigDave. Can you elaborate on what you mean by "rinse"? Is there a "rinse" position on the valve?

Thanks Watermom. Out of curiosity, do you add DE into your filter also? Does everyone? What does that do to the warranty of the filter? Do I dare tell my builder?

1) You don't have to use DE
2) You only use a little bit, just enough to raise PSI 1lb.That usually means 1/4 to 3/4 of a cup.
3) DE shouldn't hurt your grass, but it will kill many kinds of bugs.
4) It won't affect your pool's warranty, but may affect the filter warranty, but shouldn't as it won't damage the filter.
5) I would not tell the builder. Not his business.

I do sometimes add DE but not routinely. You can read more about adding DE to a sand filter in the following thread:>

http://pool9.net/de-test/

I cannot imagine how adding DE would affect the filter negatively. Filters are made to trap debris. Basically, DE is just debris that is caught by a sand filter just as any other debris would be.

Thanks everyone for your very helpful input. Went ahead and told the builder to go with sand. However, I noticed that he will be installing the largest filter available for a Pentair Triton II, the TR-140C. which will need 925lbs of sand (really??). The pump will be a Pentair Intelliflo VS pump and will have an attached spa. The pool capacity will be ~16k gallons. He explained that we needed the larger filter because it’s the only one rated to flow the amount of water that we need for the spa to function properly. The spa only holds ~850 gallons. Does this sound right? I think I’m going to need more than 1/3 of a cup of D.E.

I will be anxious to try D.E. but I think I'm going to hold off and see what it looks like without it. I will add the skimmer sock immediately once we're up and running.

Yes, you can say the brands and models. Give as much info as you can to the equipment guys on the forum before you commit.

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Originally Posted by FormerBromineUser

Yes, you can say the brands and models. Give as much info as you can to the equipment guys on the forum before you commit.

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Point taken. Will edit my previous post.

While 925# seems like a lot, you ARE filtering a spa, which I presume requires a much higher flow rate for all the jets if it's a single pump--I'm guessing as I know nothing about spas. But he's 100% correct that the filter MUST have a greater capacity than the pump. With filter that large you may WELL see fantastic performance that makes DE unnecessary. You can always try it, and if you don't like it or you put in too much, you simply backwash and VOILA! it's gone!

Be absolutely certain he installs surge protection for your VS pump, not just GFCI. They are very sensitive to surges and lightning, having electronic circuit boards. While they do perform better than a 2-speed pump, they are more sensitive because of the electronics.

These days, with all the electronic appliances, surge protection is everywhere. We have to have it on our washer and dryer, even though the dryer is gas, because they are electronic. We have lost too many coffee makers till I put a surge protector on the latest one! We even have a fridge and range that have them on them (gas stove, electronic controls)!

Rinse is a setting on most multiport valves. Your builder may be installing the full flow valve as flow for the spa appears to be the factor driving filter and pump selection. I don't know if the full flow valve option has a rinse position. There is an MPV option for that filter but it would probably restrict flow.

I think your builder is offering a nice filter and you'll be happy with the water quality. Don't worry about the half-ton of sand, you'll never have to replace it (unless you use Baquacil or cellulose DE substitute).

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Originally Posted by CarlD

While 925# seems like a lot, you ARE filtering a spa, which I presume requires a much higher flow rate for all the jets if it's a single pump--I'm guessing as I know nothing about spas. But he's 100% correct that the filter MUST have a greater capacity than the pump. With filter that large you may WELL see fantastic performance that makes DE unnecessary. You can always try it, and if you don't like it or you put in too much, you simply backwash and VOILA! it's gone!

Be absolutely certain he installs surge protection for your VS pump, not just GFCI. They are very sensitive to surges and lightning, having electronic circuit boards. While they do perform better than a 2-speed pump, they are more sensitive because of the electronics.

These days, with all the electronic appliances, surge protection is everywhere. We have to have it on our washer and dryer, even though the dryer is gas, because they are electronic. We have lost too many coffee makers till I put a surge protector on the latest one! We even have a fridge and range that have them on them (gas stove, electronic controls)!

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Whew! Thanks CarlD. This builder said he has over 28 years of experience, and for a moment, I thought were being taken.

I will try D.E., just because I’m more curious than anything, but will wait a few weeks after startup to see how it looks without it.

As for surge protection, the builder actually recommended it. We do get some severe lightning storms over the summer months here in the Denver metro area so better safe than sorry. He just installed one on a pool that was struck 3 times before the owner got fed up (I would have been fed up after the first time). He’s telling us to go ahead and purchase the surge protect on our own as he would have to mark it up if he were to purchase it, $200 vs less than $100 from an online store I found. I take savings anytime.

He’s also having us purchase the SWCG which I have more questions on that. Should I start a new post in SWCG? I’m looking at the Hayward Goldline but not sure which one? Size?

Thanks again for all your help, and for everyone else’s help for that matter. You’ve made me feel a lot better about the filter…and the builder. I will be posting several more questions around the forum so please keep the good information flowing. I can use all the help I can get.

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Originally Posted by BigDave

Rinse is a setting on most multiport valves. Your builder may be installing the full flow valve as flow for the spa appears to be the factor driving filter and pump selection. I don't know if the full flow valve option has a rinse position. There is an MPV option for that filter but it would probably restrict flow.

I think your builder is offering a nice filter and you'll be happy with the water quality. Don't worry about the half-ton of sand, you'll never have to replace it (unless you use Baquacil or cellulose DE substitute).

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Thanks BigDave. I'm sure the builder will review everything once the pool is done, but I'll keep this thread to remind me once the big day comes. Thanks again for all your help.

Well, as far as SWCG goes, you can go either way. Personally, I'm happy with my Autopilot.
First off, while an SWCG can make life easier, it won't make it A LOT easier if you're always and home and good at maintenance. Because if you are, you'll spend 2-5 minutes a day testing and adjusting your water and 15-45minutes once a week, unless you hand-vacuum. If you travel a great deal and have to leave the pool unattended for days or even a week at a time, an SWCG can be a big help.

It will NOT save you money. It will cost more in initial cost to run than buying bleach and Liquid Chlorine. Plus figure every 5 years you'll need a new cell...at aprox $500/pop. That's at least 5 years worth of bleach/chlorine on a 16000 gallon pool.

Still, this builder sounds like he knows his business, recommended the surge protector, and recommended you get it separately. So I'm guessing he'll know how to install the SWCG, which includes the necessary wiring. I did my own and merely piggy-backed it off the pump's timer (220v) and plumbed it in. But I'm an do-it-yourself addict. If you DO have him install it, be sure to have him put quick-release cutoff valves on either side of the cell. Most SWCG cells have their own filter screen that needs to be cleaned from time to time and it's MUCH easier to do it if you just shut off the pump, flip both ball valves, and open it up and clean it. Also, if you have to service or replace it, it's easy enough.

We do have a couple of SWCG experts here, PoolSean comes to mind, but I haven't seen him posting in a while.

Just an aside here, if you do get DE (Diatomaceous Earth), get it from a Home Depot kind of store. Years ago when I was being pool-stored, I asked them for DE and they sold me the cellulose product saying it was the same thing. I used it and it made a gooey mess of my sand and I had to replace it.

Also, thanks (Carl-?) for cleaning up my post!

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Originally Posted by FormerBromineUser

Just an aside here, if you do get DE (Diatomaceous Earth), get it from a Home Depot kind of store. Years ago when I was being pool-stored, I asked them for DE and they sold me the cellulose product saying it was the same thing. I used it and it made a gooey mess of my sand and I had to replace it.

Also, thanks (Carl-?) for cleaning up my post!

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Just make sure the package says 100% Diatomaceous Earth. And don't buy more than a 10# box.

Buy any Pentair products through the builder - Pentair has gutted their direct-to-consumer warranty. The rule I hear most often about SWCG sizing is to oversize for the pool. The SWCG cell will last longer between replacements as it won't have to run as much to make the same amount of chlorine.

BD, he said he was looking at a Hayward SWCG, not a Pentair. I seem to remember something about Pentair's SWCG being the most trouble-prone.

But oversizing the SWCG is a good idea. Something that can handle between 25k and 30K at a minimum.

A big +1 on oversizing the SWCG.

While it's true it won't save money, I find the convenience worth it (I do not enjoy pool maintenance).

Another important thing to keep in mind is to only use the SWCG to maintain chlorine level. Do not use it to raise CL or shock the pool. Using it only to maintain CL will greatly extend the life of the cell (I learned this the hard/expensive way).

It seems to be the consensus here that the Hayward and Autopilot units are the best. I have the Aqua Rite (now made by Hayward) rated for 40k gal (our pool is 20k gal) and would recommend it. It was installed in early 2004.

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Originally Posted by FormerBromineUser

Also, thanks (Carl-?) for cleaning up my post!

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Nah, it was me! ;)

Wow. Got a bit of catching up to do. Crazy day at work so I couldn’t access.

CarlD – the reason for the purchase of the SWCG is for peace of mind. When we take a vacation it’s usually for a couple of weeks. Plus, I tend to work late, and sometimes get home in time to eat, help the kids with homework, and kiss the wife good night. Weekends too..like tomorrow (Ugh). Hope I get to use the pool at some point once it's done.

I am very interested in the quick access of the SWCG. Is there any way you can send me a pic of your setup so I can show the builder? I like doing things myself also, but I can’t seem to find any time to do anything anymore.

BigDave – thanks for the advice on the DE. I tried not to purchase anything from pool stores on our old pool. Will try to do the same with this one.

CarlD & BigDave – To tell you the whole story, the Pentair Intellichlor IC-40 was included in our bid. I told him I’d rather have something else after reading all the posts here and on other sites. Amazingly, he agreed. The only good point in his offer is that it would have been included in the 3 year warranty that he was offering since we’re purchasing the pumps (extra one for the water feature), heater and filter from Pentair. Tempting, but decided I didn’t want to deal with a problem a year or so down the line.

Funny, our previous pool builder wasn’t’ quite so agreeable and forthcoming…and he was our neighbor. I think I will go ahead and start a post on SWCG category to get some more input before this gets too much bigger. This is kind of fun.

Thanks again for all this info.

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Originally Posted by JimK

A big +1 on oversizing the SWCG.

While it's true it won't save money, I find the convenience worth it (I do not enjoy pool maintenance).

Another important thing to keep in mind is to only use the SWCG to maintain chlorine level. Do not use it to raise CL or shock the pool. Using it only to maintain CL will greatly extend the life of the cell (I learned this the hard/expensive way).

It seems to be the consensus here that the Hayward and Autopilot units are the best. I have the Aqua Rite (now made by Hayward) rated for 40k gal (our pool is 20k gal) and would recommend it. It was installed in early 2004.

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Thanks for the heads up JimK. Wow, that's 10 years, no issues? Can you give me the model number if it's still being made? I'd like to do some research.

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Originally Posted by Toybuilder

Thanks for the heads up JimK. Wow, that's 10 years, no issues? Can you give me the model number if it's still being made? I'd like to do some research.

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In June 2008 the original cell was replaced. Not knowing any better, and before I found this forum, I was using the "Super Chlorinate" setting on a regular basis to boost chlorine to fight the start of algae (slick liner). The second cell is still in use (I've learned a lot on this forum and am no longer "pool stored" ;) ). This time I'm only using it to maintain chlorine, and as you can see it has lasted much longer.

In May 2009, the main board had to be replaced. I have since learned I probably could have fixed it myself for much less (I love this forum!).

Other than that, I've not had any issues with it.

I don't have a model number, other than it's called "Aqua Rite". It was made by Goldline Controls. I understand now it's owned by Hayward. I'm pretty sure this is the same unit (the only difference I see are the graphics on the unit);

http://www.hayward-pool.com/shop/Pro..._27501_14006_I

As was said, just like with the filter, make sure you go oversized! Personally I'd recommended the unit rated for 40k gal for your pool.

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Originally Posted by Toybuilder

CarlD – the reason for the purchase of the SWCG is for peace of mind. When we take a vacation it’s usually for a couple of weeks. Plus, I tend to work late, and sometimes get home in time to eat, help the kids with homework, and kiss the wife good night. Weekends too..like tomorrow (Ugh). Hope I get to use the pool at some point once it's done.

I am very interested in the quick access of the SWCG. Is there any way you can send me a pic of your setup so I can show the builder? I like doing things myself also, but I can’t seem to find any time to do anything anymore.

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That's the reason I installed my SWCG--I'm away during the swimming months more than in the past. I use the CLOSED position on the multivalve and the lower black and orange valve to isolate the SWCG cell. The controller/power supply is on the wall behind the filter.

https://lh5.googleusercontent.com/-i...520Control.jpg

https://lh5.googleusercontent.com/-S...2/SaltCell.jpg

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Originally Posted by JimK

In June 2008 the original cell was replaced. Not knowing any better, and before I found this forum, I was using the "Super Chlorinate" setting on a regular basis to boost chlorine to fight the start of algae (slick liner). The second cell is still in use (I've learned a lot on this forum and am no longer "pool stored" ;) ). This time I'm only using it to maintain chlorine, and as you can see it has lasted much longer.

In May 2009, the main board had to be replaced. I have since learned I probably could have fixed it myself for much less (I love this forum!).

Other than that, I've not had any issues with it.

I don't have a model number, other than it's called "Aqua Rite". It was made by Goldline Controls. I understand now it's owned by Hayward. I'm pretty sure this is the same unit (the only difference I see are the graphics on the unit);

http://www.hayward-pool.com/shop/Pro..._27501_14006_I

As was said, just like with the filter, make sure you go oversized! Personally I'd recommended the unit rated for 40k gal for your pool.

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Thanks again JimK. I will keep that in mind.

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Originally Posted by CarlD

That's the reason I installed my SWCG--I'm away during the swimming months more than in the past. I use the CLOSED position on the multivalve and the lower black and orange valve to isolate the SWCG cell. The controller/power supply is on the wall behind the filter.

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Wow. I'm impressed. Want to take a trip to Denver in a few monnts? Is yours rated for a larger pool also? I guess my big question would be how big should I go. JimK is suggesting 40k. Does it state on the models how big a pool it will handle?

I've started my new post in the SWCG category, http://www.poolforum.com/pf2/showthr...885#post128885.

Guess we can pick this up over there.

Thanks. No thanks. Yes. While PoolSean is the best on it, I think 50% to 100% greater than your pool's size (16k) is more than enough. With some, like mine, you can mix and match controllers and cells to get the ideal setup. If I were to decide to, I could put a bigger capacity cell in my manifold and just re-set the controller to run it. This unit can also act as the pump's timer, and, I believe, select between high and low speeds, but I didn't mess with what was working fine. It can even run an acid injection pump, too. May also brew the morning coffee, but I have not gone that route yet....

Ha! And you without coffee???? Go for it!

Who's without coffee? I'm the house coffee maven!:D
Today is fresh-ground Ethiopian! Yum!

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Originally Posted by CarlD

Thanks. No thanks. Yes. While PoolSean is the best on it, I think 50% to 100% greater than your pool's size (16k) is more than enough. With some, like mine, you can mix and match controllers and cells to get the ideal setup. If I were to decide to, I could put a bigger capacity cell in my manifold and just re-set the controller to run it. This unit can also act as the pump's timer, and, I believe, select between high and low speeds, but I didn't mess with what was working fine. It can even run an acid injection pump, too. May also brew the morning coffee, but I have not gone that route yet....

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Like yours, the Aqua Rite has different cell size options that can be used with the same control unit. I believe the three options are 15k gal, 25k gal, and 40k gal.

IMO, while the 25k gal size would probably work fine for a 16k gal pool (though I don't know how the spa impacts this) the 40k gal size cell would offer the best value as it would last the longest.

Toy builder, though I only have first hand experience with the Aqua Rite, I'd have no problem recommending either brand based on what I've read. :)