How Often Backwash?

[ThaSatelliteGuy]

Ok...

Have a 13k above ground Intex with an Intex 2500gph pump/filter and an Intex swg. All is mostly well... except having to clean/replace filter every 12 hrs. It got REALLY ANNOYING.

So I bought a 200# sand filter rated for 52gpm (3300gph) This filter claims to be rated for a 21k pool so it's 35% overkilled, and at 2500gph, this system should flip my water every 5 hrs or so. I run it 24/7. I plumbed the sand filter between the Intex pump and swg, and simply removed the cartridge. On the plus side, the pool has not been so clear since I bought it. (about 60 days old) I mean WOW did it make a difference! So clear you cant even estimate the depth.

BUT, I am still having to backwash the filter at least once a day, sometimes morning and evening. And I get a little sand in the pool. (But at least its clear enough to see the bottom) Is this normal?? I mean backwashing is WAY LESS ANNOYING than cleaning the cartridge that much, but still, should I be having to backwash THAT much?

[CarlD]

That seems excessive for such a moderately sized pool.

Why do you think you have to backwash that much?
Is your pressure rising that much each day?
Normally I backwash when my pressure rises from 20psi to 25psi.

Did you fill your filter with pool filter sand? It comes in 50# bags specifically marked "Pool Filter Sand". If you didn't you should replace the sand with the proper stuff. It's not expensive.

However, when sand is new there can be a tendency for some to come into the pool for a little while.

OK. now let's assume that there's nothing wrong with your filter. You said you had to change the Intex filter every 12 hours--and whether you are washing them or replacing them, I agree--that's far too much. But if they are clogging that much then it's because something is falling into the pool.

We've had a ton of pollen this season--I use skimmer socks and they constantly come up caked with pollen. If you are in the NE that may be part of your problem.

I also hate to say this, but your pump MAY be a little small for the task. I don't know the HP on it but usually for this size pool a 1/3 to 1/2 hp pump is perfect. But let's rule out all the other possible causes first, before we go spending your $$$!

[ThaSatelliteGuy]

Ok, why do I think?

1. For the typical agp, you could probably say I have high usage. My ex and daughter live next door and use it constantly...family of 8. My gf lives across street with 2 kids. myself, and partied last weekend with a family of 7.

2. I have had pollen issues and I'm partially under two trees. For about 3 wks, there were constant pollen "caterpiller" foaties, pale yellow dust clogging my cartridge and cloudy water, and full skimmer everyday. But that has mostly passed. Even on the cartridge, the pool had mostly cleared, and to my surprise, the trees havent been visibly dropping much garbage in the water at all. (tho I expect fall to be interesting)

3. Possibly not enough pump. Idk the hp rating on it, but it seems to move plenty of water. And it is 2500gph. (I do realize it's an intex and may not really do that)

And for the pressure, it rides between 6 and 7 psi. When it hits 10-11 I have to backwash due to skimmer no longer being effectively pulled down.

For the sand, the filter called for 200# in the advertisement. The instructions called for 2/3 full. It ended up taking 6 .5cuft bags from Home Depot to make it approx 2/3. Yes, pool filter sand, but no weight on bag. They felt 30-40-ish so it should have 200#-ish

Any of this help??

[Watermom]

Typically we don't recommend backwashing until you are at 8-10psi over clean filter pressure. Your psi numbers seem a little low to me. My clean pressure is usually around 12 I think and I typically backwash at about 20ish.

[ThaSatelliteGuy]

Well then the pump maybe my problem because when the pressure rises from 6 to 10-11, my flow drops to nearly nothing..skimmer not skimming, robot not robotting. Also, because it's Intex, I had plumbing issues. So, if pressures need to be higher, I'll need to upgrade a couple rubber couplings to the metal-covered rubber couplings, cuz I dont believe the ones I have will hold as they are already swelling from the pressure at 10psi. It's really sad that Intex feels the need to stick it to us like that with their fittings.

[Poconos]

Something else that could cause low pressure is a suction side restriction but not in your case. It sounds like you're doing everything right. Upping the pump size just to get higher pressure isn't what you want to do. Your pressure is climbing almost 100% which means dirt is being caught. If you up the pump size ypu'll just ram dirt through the filter.

Some things to try. If your multiport valve has a 'closed' position on it, set it there and fire the pump up momentarily to see what the blocked flow pressure is. Also this will pressure test your questionable couplings. That will give you an idea how close the 11 psi is to the limit. Maybe that's normal for an Intex pump. I have no idea.

Another thing to try is to put something on the end of your backwash hose or pipe to catch what comes out. Maybe a skimmer sock or even just a sweatsock. That will give us another bit of info.

Keep at it, you'll figure it out. There is always an explanation.
Al

[CarlD]

I'm still concerned about the sand. Normally, with a 200# filter you get 4 50# bags of filter sand and just use that. You MAY consider doing a replacement as 50# bags are about $5-$6 usually so that's maybe $25.

Then again, has the pollen falling off eased the frequency of backwashing at all?

[ThaSatelliteGuy]

Ok multiport valve "closed" I got 11 - 12 psi. So that's all the psi the intex has got. So in reality, Ive got 6psi clean, and 10-11 psi when i need to backwash. So my pressure climbs almost 100% and when I backwash, it does turn grey then clear about 2 min later.

In the end, if I have to backwash once a day, it still beats the heck outta washing those cartridges once or twice a day, and except for the water and salt, no cost. My pool is SO CRAZY CLEAR now compared to before, that 2min a day backwashing I think I can live with.

As for the sand, it is pool filter sand. The only question is how much as the bags said .5cuft instead of weight. I use 50lb bags of concrete(not 80) everyday. These bags of sand were not that heavy...garaunteed. But I have a mud hole next to my equipment, that I need sand for. I will buy a couple of these bags for that purpose and weigh them for GP to see how much sand is in the filter, but from my estimate of weight of bags, and how much I got on the ground, I'm betting almost a perfect 200#. I'd say give or take no more than 15# either way.

Oh and the pollen... I changed to sand filter after the pollen fell off already so I have no comparison.

[Watermom]

Just a little info for you. If you post and then two minutes later think of something you forgot to write, you can edit your post instead of writing a new one. Just click on the blue EDIT button in the lower right-hand corner of your post.

[Poconos]

Sat Guy,
I merged your two posts. You may be limited to the number of posts so this gives ya one more. We're still not sure how the various user groups are structured yet.

On your pressure. since you now know the pump limit I'd give a couple psi margin to backwash. Probably about 9 psi. The grey color says you're catching something and eventually you should get it all.

Enjoy your pool.
Al
PS: curious about your username.