Buying new de filter and pump

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C

consoleman

0
Feb 18, 2014
191
Houston, TX
Im about to pull the trigger on a new pump (superflo 2speed) and de filter (FNS 48) but wanted some help regarding hp.

current setup
1 pool pump for filtration
1 booster pump for polaris (increase flow to all returns)
1 spa jets pump (im not replacing this 20yr old pump yet)
5 returns + 1 spa return
maybe 20' from skimmer to pump



1.my current 3/4 hp singlespeed pump pulls 60gpm @20 head (1.5" pvc). I want a 2speed 1 hp that pulls 85gpm or a 3/4 hp that pulls 70gpm. I plan to run the pump on high setting (3450 rpm) during part of the summer so that my poolskim works better. Will a DE fns 48 handle 85gpm?

2. Backwashing, I read that its best to backwash at 2000-2400 rpm. My pump only runs at 1750 or 3450 rpm. Will 3450 be ok?

3. Can i vacuum to filter at 3450 rpm?
 
Honestly speaking, the Pentair QuadDE line is superior to the FNS line (in my opinion). I have a very oversized QuadDE for my pool volume (QuadDE-100 on a 15k gallon pool) and I never backwash anymore. I just tear it down twice per year and recharge it fully from there. It saves me a lot on DE costs. Also, this year I skipped the Sept tear down and it's going on a full year with no backwashing....still running like a champ and it's only in the last month that I've noticed any slowdown in flow.
 
joyful,
I heard that the cartridges inside the quad aren't quite like the grids from a normal de filter (material wise) and that they dont last as long. Also, that if you get algae on the cartridges that its a big pain removing the algae. I orginally wanted the quad, i guess i may have to look into it.

Bob,
I had it right in front of me. I guess the "2.5 gpm per sq ft of filter area" threw me off. Thanks

- - - Updated - - -

Also, am i reading the pentair superflo manual right? It states that when running the 2 speed pump at the lower setting I will have 0 gpm if i have more that 20' of head? My pump is at least 20' from the skimmmer.

http://www.pentairpool.com/products/pumps-inground-superflo-high-performance-pumps-165.htm
 
I'm out right now and can't respond fully but what you've been told is total B/S. Will respond in more detail later.


Sent from my iPhone using Tapatalk
 
consoleman said:
joyful,
I heard that the cartridges inside the quad aren't quite like the grids from a normal de filter (material wise) and that they dont last as long. Also, that if you get algae on the cartridges that its a big pain removing the algae. I orginally wanted the quad, i guess i may have to look into it.
Click to expand...


OK, let me answer these.

The QuadDE cartridges are made from spun polypropylene fibers. The "grid style" mesh bags that cover FNS type DE filters are typically made of spun nylon fibers. The reason why? Because nylon is a very flexible fiber (that's why you can make clothing out of it) and polypro can be made into a rigid fiber. So, if your going to make a "cartridge-like" device, you could not possibly use nylon very easily without also having to use some other kind of binder to make it stiff enough. Polypro, all on it's own, can be made rigid. So, in an FNS style bag setup, it's easy to use nylon as the gridding material for the DE to be captured upon while in a Quad configuration filter, polypro is the better choice of material for the gridding.

Here's the point - the choice of material that holds the DE is somewhat irrelevant because it is the DE that does the filtration, not the gridding material. Now you might be able to make some arguments about life expectancy but I would argue that polypro is more stable than nylon.

As for the algae comment, that's just more pool lore and ignorance than anything else. Algae is not a filtration issue, it is a chemical issue. A pool that has algae problems has them because the pool water chemistry is not being properly maintained, filtration has nothing to do with it. The only thing that can be said about algae and filters is that if you do have a green swamp to clear, cartridge and DE filters (all DE filters) will be slower to clear them than a sand filter because the elements in the cartridge or DE filters load up faster with dead algae and require more detailed cleaning than a simple backwash that one can perform on a sand filter.

But there is no interaction between the algae and the gridding material; that is simply nonsense.
 
consoleman said:
Joyful,
Thanks for taking the time to explain that in detail. Leslies says i need a 1.5 hp or 2 for that filter. Is that true? I wanted to buy a 1 hp with 1.5" plumbing.
Click to expand...
No that isn't true. The lower the HP the better for filtering. If you have a separate spa jet pump, then I would go with the 1 HP. That is more than enough for that pool and setup.

1.my current 3/4 hp singlespeed pump pulls 60gpm @20 head (1.5" pvc). I want a 2speed 1 hp that pulls 85gpm or a 3/4 hp that pulls 70gpm. I plan to run the pump on high setting (3450 rpm) during part of the summer so that my poolskim works better. Will a DE fns 48 handle 85gpm?
Click to expand...
Why do you think you need such high flow rate? Most skimmers work fine at about 25 GPM. No need for more than that and in fact, if you have much more than that, the debris will tend to move right by the skimmer because it is moving too fast. That may be why you think you need a poolskim. I have a 20k pool AND 2 skimmers and they work just fine with a 1/2 HP pump running at low speed.

Also, note that you could replace your current motor with a two speed and save a few hundred.

Lastly, why are you changing filters? Going from the 36 to the 48 is only a 1/3 increase.
 
consoleman said:
I just saw that the quad de only comes with 2" plumbing. I dont have much space to add a reducer. hmmmmmm always somthing
Click to expand...

If you have the room, cut back the 1-1/2" pipe connected to the filter a little bit and just add the reducer back in. It's not that hard to do...if you post pictures of your equipment pad and what you have to work with, plenty of folks here can help you do the layout and give advice.
 

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mas985,
I have one skimmer and one pool skim and a single speed motor. I have a valve on my return that let me adjust whether the water returns to the spa or pool. I usually just crack the spa so most of the water goes to the pool. If I dont do this my poolskim doesnt work right (it never sucks the trash down).

Im changing filters because I have a 18 year old filter I can no longer find a replacement band for and its leaking.


Joyful,
I will try and post a photo but had a hard time doing it earlier
 
consoleman said:
I have one skimmer and one pool skim and a single speed motor. I have a valve on my return that let me adjust whether the water returns to the spa or pool. I usually just crack the spa so most of the water goes to the pool. If I dont do this my poolskim doesnt work right (it never sucks the trash down).
Click to expand...
Then something isn't set up right. Like I said before, I have two skimmers running at about 35 GPM total so much less then you and they work fine.

Do the skimmers have weir doors on the front and do they work?
 
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