Sand or Cartridge Filter for New Pool

[BigDave]

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.

[Watermom]

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.

[Toybuilder]

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?

[CarlD]

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.

[Watermom]

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.

[Toybuilder]

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.

[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.

[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)!

[Toybuilder]

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