Best Filters & Filter Media: Pentair 59023400 Complete Element Grid Assembly Replacement 48 Square Feet FNS Plus Pool and Spa D.E. Filter

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  • Product Dimensions: 17.8 x 18 x 29.5 inches ; 24.4 pounds
  • Shipping Weight: 28.1 pounds (View shipping rates and policies)
  • Domestic Shipping: Item can be shipped within U.S.
  • International Shipping: This item can be shipped to select countries outside of the U.S. Learn More
  • Item model number: 59023400


This complete element grid assembly is designed to use with Pentair 48-square feet FNS Plus pool and spa D.E. filters. Measures 17-3/4-inch length by 29-1/2-inch height by 18-inch width.

User reviews

Easily worth the extra ~$50.00 over the cost of just the grids to have the pre-assembled, one piece, drop in unit with,new manifold, and air-release valve. The only differences visible to me were the air-relief valve and the manifold exit pipe, which is about an inch or so shorter than my original. Lacking a positive seal at this point could create a path for unfiltered water & DE to bypass the grids and be returned to the pool. I don't believe this is an issue, My pump has been running continuously for 75+ hours since replacing the grid assembly. There are still traces of DE in the pool, but given the fact that it had been running with defective grids for 7-8 months, I suspect there was enough DE (etc) in suspension that it may be a week or more before I can be certain that the DE leak is "fixed". (The water is infinitely cleaner, just not perfect.)Regarding Compatibility:I saved the original paper manual from the "NAUTILUS FNS FIBERGLASS D,E (PUREX TRITON) FILTER" which I believe I purchased in the late 1990's. The term "FNS PLUS" is nowhere to be found in my documentation. For my application, (except for the manifold return discrepancy), the "Pentair 59023400 Complete Element Grid Assembly Replacement 48 Square Feet FNS Plus Pool and Spa D.E. Filter" is a plug & play replacement for a "non-FNS Plus" Filter.I'll report back if time proves me wrong,
was struggling to get pool cleared since opening it. I admit I had a problem at end of last season and decided to just close it as I ran out of time to stress over it. So when I opened it this year, it was GREEN! tried the usual shock, etc. and even went as far as using Green out.Green out actually worked but water stayed cloudy. tried water clarifier and multiple back washes...still NG. used a grid cleaner , no change. used muriatic acid and gave the grids an acid bath. no change. took the grid assembly apart again and gave a slow, intense inspection looking for any tears. ( forgot to mention that the pool store specialist told me that if DE was getting back into pool, it would settler on bottom of pool; that did not happen so I did not think the grids had any tears). Well, he was mistaken because I did find several tears or minute holes in more than one grid. since I had only changed the grids myself a few years ago with an online replacement set, I decided to spend more and get an assembled unit. Pool finally cleared up and after balancing the chemicals I actually had the water TESTED AND IT IS perfect! nOW IF THESE LAST A FEW YEARS, i AM HAPPY!!
I had not realized that my element grids needed to be replaced. I was having trouble with DE coming back in the pool. I am embarrased to say I think my grids were over 17 years old! LOL I got a new diaphragm for my Baracuda pool cleaner, and these easy drop-in-grids (my manifold was cracked anyway, and I wanted to make sure everything matched), and my pool is literally cleaning itself again. My oh my - what a dramatic difference. I had forgotten why I started cleaning it myself it had gotten to be so problematic. Now I literally only have to scoop the leaves, add water, and maintain chemicals -- a piece of cake! No brushing anymore! Just be sure to get the size that matches your filter. Perfect! Hope they last what I know is more expected like five years.
When it comes time to replace the grids in you DE. Filter it's going to cost you $xxx.xx so for just a little more you can get this complete set up... Manifold, base, grids, etc... All put together and ready to drop in place. It took a few minutes to backwash the old grids, and then simply the time it takes to remove the old and drop in the new... 15 to 20 minutes all the way through adding filter media.I will say I gave 4 stars because I bought this same set up previously and the grid fabric unraveled in less than a year. So why would I purchase again? Hoping that last experience was a fluke and am giving it one more try... The original grids that came with the pool lasted 8 years... Same brand, etc... As this set up, so I'm hopeful I will get better longevity out of this set.
Would have given it 5 stars but the assembly came poorly packed with little to no bubble wrapping or padding. As a result, one of the outer edges of the bottom spider grid broke off. Also ended up opening the wrong end of the box since it wasn't marked and it was delivered upside down. Went ahead and installed it anyway. Installation was quick and easy and everything fit perfectly. After priming the grids and running the pumps for about 4 hours, everything seems good to go.
I liked that the unit came fully assembled as it made for very easy installation. Took less than an hour beginning-to-end to replace the existing unit. Worked perfectly, I was able to load DE and had none flow through into the pool for the first time in years. Only suggestion I would make is to have the company send along an o-ring to replace the existing one on the manifold pipe since the unit is apart and there is good likelihood this is contributing to issues that may be happening with the filter. overall I am satisfied with the purchase and would buy from them again.
The grid is a perfect replacement for my Pentair setup. I somehow managed to crack much of the manifold on the top, and the grids were due to be replaced anyway, so this worked well. It comes completely assembled outside of sliding in the pressure relief on top. That took about 7 seconds, and then you can just put it right into the DE filter shell.We'll see how long it lasts for durability, but so far, so good. What sold me was free same day delivery and it was $150 cheaper than what I could get at the local pool stores.

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