CYA coming back through returns?

I added some salt this morning and some CYA as is recommended (previous levels were about 30 but I had drained a good bit of water to lower the Ca level -- another story). Pool is about 35,000 gallons.

Anyway, I added it slowly to the skimmer (5 lbs over about 3-4 minutes). Then I notice that the returns are shooting some of this stuff out. It looks like at least 50% of it came back out the returns.

Shouldn't the filter get this? I initially thought I might not have added enough DE when I backwashed, but this stuff is much bigger than DE.

Any thoughts?

Thanks,
Mark

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Originally Posted by HooStat

I added some salt this morning and some CYA as is recommended (previous levels were about 30 but I had drained a good bit of water to lower the Ca level -- another story). Pool is about 35,000 gallons.

Anyway, I added it slowly to the skimmer (5 lbs over about 3-4 minutes). Then I notice that the returns are shooting some of this stuff out. It looks like at least 50% of it came back out the returns.

Shouldn't the filter get this? I initially thought I might not have added enough DE when I backwashed, but this stuff is much bigger than DE.

Any thoughts?

Thanks,
Mark

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Make sure you have your filter set to filter, as opposed to recirculate or some such.

There is only 1 setting. There is no way to bypass the filter. Water comes straight from the pump to the filter.

Then something is very wrong with your filter.

Michael

Hoostat,

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There is only 1 setting. There is no way to bypass the filter. Water comes straight from the pump to the filter.

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The multiport valve would be AFTER your filter. Are you saying the water goes from the filter directly to the pool with no way to backwash, etc?

The water comes from the skimmer and/or main drain and into the pump. From the pump it goes to the filter and then to the heater. From there it goes to either the infloor system or main returns (depending on valve settings).

For the spa, the setup is the same except that the water comes from the spa drains and goes back via the spa returns.

This seems like it should be pretty standard. Am I missing something?

Just added: backwashing is done by moving a lever on the filter. when I move the lever, the backwash goes into the drain instead of the pool.

Hi, Mark,

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backwashing is done by moving a lever on the filter. when I move the lever, the backwash goes into the drain instead of the pool.

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That's the valve we're talking about. We just wanted to make sure it has no other position than "backwash" and "filter". Many valves have several positions at that point including recirculate which does bypass your filter.

Sorry we got off the topic.

Anyway, unfortunately, I'm not a DE guy but you have something wrong with that filter. This post will bump you back to the top and get you noticed by a DE expert.:)

Normally the backwash valve is considered separate from the filter (right before and after it). Maybe yours appears as a single unit.

I think you're right.. CYA is bigger than DE... if you didn't add enough DE it would still be caught by the grids.

I think you'll need to open your filter and check the grids for tears.

BTW, CYA disolves slowly... it normally is caught by the filter and disolves from there. If the CYA gets through, your filter isn't filtering.

Robert

It turns out that there is a small hole in the plastic piece at the bottom of the filter -- the piece into which the grids are placed. It is supposed to have a tube sticking out of it as an air release mechansim. Instead, it just allowed things to bypass the filter. I am guessing that something heavy, like CYA, was especially prone to go out this hole since it was near the bottom of the filter.

We plugged the hole until we get the replacement part (this week). There is an air release valve on the top also, so we should be safe for a short time period.

Anyway, thanks for the help.

We plugged the hole until we get the replacement part (this week). There is an air release valve on the top also, so we should be safe for a short time period.

Anyway, thanks for the help.[/QUOTE]
To clarify for all above posters, the unit in question is the 'old style' or bump DE filter (Hayward's E-C series). There is no multiport valve, only an inlet at the bottom, outlet (return) on the top and a drain valve on the bottom, opposite the inlet. Therein lays a key difference between sand filters and DE filters, sand filters from the top down - DE from the bottom up. (For y'all with multiports, go look at a friends' pool with a sand filter - you'll notice that the multiport 'settings' - filter/ backwash- are 180 deg reversed). Cleaning this unit involves shutting off the system, releiving the filter pressure and pumping a handle on the top of the unit to 'mix up' the DE & crap (the DE is only coated with 'crap' at it's surface), when you restart the pump, the pressure has magically dropped without backwashing, nor loosing a drop of water. True cleaning has been dicussed elsewhere.
http://www.poolforum.com/pf2/showthread.php?p=1671

HooStat; you don't have a Hayward filter, but I have no idea who made yours. An air relief tube at the bottom doesn't make sense as air rises in water. However, my advice remains the same; clean and check the entire grid assembly for cracks or holes when you have it open to replace the air relief stem. BTW, if cya granuals went through the hole, you can bet that a lot of DE will go through the same hole when you charge the filter or bump it.
(this is my first attempt to provide a link, hope it works ;) )