Decision on Zeobrite or Sand replacement

[TMan]

Thanks for the ideas.
Waterbear - That's what I was thinking, ammonia. But as it stands now all the ammonia Does pass thru the filter so any ammonia caused to be released from the z-lite by the low % salt solution won't really affect the overall chemistry.
gwrace - Same answer; I don't think it has much, if any effect; SWG & Zeolite
Duraleigh - That is where my post came from - 6 year old sand and we run pumps pretty much year-round here in TX - So figure 3x the time of most 'normal' run times in colder climates. Though I haven't done a complete work up on the water using my PoolSolutions kit, the fact is that you can see the dead algae come through the return nozzle when vacuuming deep end where most of the algae settled, it's a 'cloud'. Very, very fine.
Hence the original question - Time for replacement sand, or zeolite?
Remember the filter has worked fine until this winter/spring, and it appears the filtering ability now reduced. Pump pressure is fine, all is operating as normal except that it's not 'filtering' the fine, very fine particles. No sand is coming out, so no laterals are broken or anything like that. And when backwashing it does expel bugs, dirt & the like so it is filtering large particles.

Duraliegh/brock - Thanks. I am leaning that way.
I have asked several pool stores about adding DE to the sand but they never heard of it. Though they have heard that their $23 Sand Filter Cleaner works well ;-)

I have decided to replace the sand.
Will update everyone later.
(100+ today in Austin! with 'rolling blackouts', time to leave work early & swim!)
Thanks everyone.

[gwrace1]

I would agree with the leave work early part. I work in Round Rock. The heat extremes this year are strange and it's way to early in the year for 100 degrees plus. The rest of the week is supposed to be in the mid 80's.

The rolling electrical blackouts are another story...

[duraleigh]

Hi, Tom,

If it's possible, try to eliminate all the other variables when you change the sand and let us know what you find out. After saying that, I have no idea how you can retain the dead algae in your pool while you change sand but maybe we'll all get an indication if your effort was effective. Good luck with it and let us know

Dave S.

[CarlD]

Ammonia is released into a chlorine filled pool if you use an SWG? Excuse me, but doesn't mixing ammonia and chlorine result in a deadly gas being produced, which is why you are warned to NEVER mix the two for home cleaning?

If you put DE in your sand filter, you'll probably have to add more every time you backwash. Since you only add a half/cup to a cup, a 10-15 lb box should EASILY last the season. I use this method as well and like it.

[waterbear]

Ammonia is released into a chlorine filled pool if you use an SWG? Excuse me, but doesn't mixing ammonia and chlorine result in a deadly gas being produced, which is why you are warned to NEVER mix the two for home cleaning?

If you put DE in your sand filter, you'll probably have to add more every time you backwash. Since you only add a half/cup to a cup, a 10-15 lb box should EASILY last the season. I use this method as well and like it.

The ammonia will be in the form of ammonium ions. These are what combine with chlorine in the pool to form chloramines (VERY simplified chemical explanation!)
From my understanding some "old time pool service guys" would put anhydrous ammonia and liquid chorine into a pool to purposely form chloramines and then reach 'breakpoint' by putting more chlorine in 24 hours later. The chloramines are eaten by algae and decolorizes it. Some commercial algae products also put ammonia compounds into the water for the same reason (Black Algaetrine comes to mind)
Also many water treatment facilities put ammonia or ammonia compounds into the water with the chlorine to form simple chloramines to prevent the formation of more toxic ones. (this has been a major headache to every aquarium hobbiest for years now and forced us to learn all about "breakpoint chlorination" even if we never owned a pool! since ammonia is MUCH more toxic to fish and other livestock than chlorine is and choramines are MUCH harder to get rid of then chlorine.)

But you are right, mixing liquid ammonia and liquid chlorine CAN release deadly fumes and should be avoided! The difference is most likely the dilution factor involved.

[TMan]

Thx waterbear. I really didn't want to start to explain that saltwater is the recomended cleaning agent for zeolite, and when it 'cleans' the zeolite it is widely known that it releases stored ammonia from the zeolite. Therefore, if you're running a swg constantly, the zeolite is constantly being 'cleaned' then ammonia is constantly being released. Obviously it will be in such minute amounts, and dilution as you point out below, that it will not be an issue what-so-ever. And to take it to a farther logical point, will zeolite ever be able to 'absorb' any amount of ammonia if saltwater is passing over it?
Which makes the whole question of ammonia release kinda moot.
My issue was that I didn't want to invest in z-lite if this cleaning ability is one of it's strong points and I was stifling it by using the media in an swg pool.
I'm replacing my sand anyway so it doesn't matter.

Guess we did end up 'splaining it, Lucy!
Tom

[TMan]

UPDATE: Replaced 250lbs of sand saturday, April 22. Today, water is 85-90% clear and clearing nicely. Added 2x40lbs bags of salt, SWG is running at 3000ppm salt level and generating nicely. The surface of the vinyl is very rough, must be algae that scaled on there. It won't come off with a stiff poly brush, but will come off with some gentle wipes with a 'green' pad. Anyone ever run into this? Guess everyone will get a green pad to wear on their feet for a week's worth of swimming!
Thanks for the tips, tricks and 'listening'.
Later
Tom

[duraleigh]

Hi, Tom,

Thanks for the follow-up. That's a very interesting comment about your vinyl liner.

It won't come off with a stiff poly brush, but will come off with some gentle wipes with a 'green' pad.

I'm not positive, but I don't think that's algae. When I review your first post, I see this:

but the problem is just like some other posters, the fine algae is going through the sand filter.

That leaves a milky-white pool which I've been vaccuming every day and haven't seen the bottom of for 2 weeks

Combining those two observations makes me think that something precipitated out of your water and has scaled on the vinyl.....perhaps calcium.

To my knowledge, algae dead or alive doesn't create a scaling condition. Nor does dead algae turn a pool milky white (to my knowledge)...more like cloudy grayish blue.

Well, if your water looks nice, that may be enough. I believe I would look at my test numbers very carefully....I think there was something else going on. Have you done a complete test this Spring?