Is my filter bad?

[RickyEarl]

Before I get to the question, some back ground. I bought a house in December with a pool that had been neglected fairly badly. My first pool. I managed through a lot of work - and a lot of help from folks here - to finally get the water sparkling, clean and perfect early this month. :-D

My neighbor's colossal Live Oak trees (the worst tree God ever plagued pool owners with) have been the main challenge. They just got through a three week period of dumping about 10 large yard bags a week worth of leaves. Now they are dropping those pollen things ("oak worms"). After a windy Sunday night, they filled my entire yard 2'' deep. I see no concrete or grass - just oak pollen. Overnight. I've never seen anything like it. Thank the Lord we are not allergic to it.

Anyway, my pool turned cloudy and green in one night from the pollen. I know it's the pollen because FC is steady around 5.0. So I decided it might be a good idea to backwash the filter to prepare it for the onslaught. But then I looked at the gauge.

I backwashed about 3 weeks ago when the needle on the gauge was close to the red marker (around 29 bar). There's a green marker around 16-17, so I figure the needle ought to stay between the two. After I backwashed 3 weeks ago, the pressure read 10 bar - far below the green level. I decided not to worry about it as the water looked clean and I knew I had added the proper amount of replacement DE (6.0 lbs for a 7.5 lb filter).

So now, 3 weeks later, the pressure is still around 10 bar. Is something wrong? As I said, prior to the pollen invasion, the water was sparkling clear, so it seems to have been working, but 3 weeks is a long time with no change, especially since I did an algae shock and a lot of leaves fell in.

Thanks

 

[JasonLion]

Did you remember to add more DE after backwashing the filter?

You have a fairly large filter. It isn't unreasonable that it might not need backwashing just yet.

Typically you backwash the filter when the pressure goes up by about 6 from the clean/starting pressure. The green/red indicator rotates so that you can set the green mark to point at the clean pressure. The previous owner may not have made that adjustment.

 

[RickyEarl]

Thanks for the reply. Yes, I added 6 lbs, 80% of what my 7.5 lb filter holds.

I wonder why he had the marker at 16-17 if 10 is clean, and now it scares me it got all the way up to around 28.

 

[JasonLion]

Running with the pressure up at 28 won't have damaged anything, but it will have dramatically reduced the amount of water that got circulated.

 

[ping]

I have a pool in similar size to yours and I also have a larger sized DE filter. My nominal pressure has never raised more than 1lb than when clean, but I have only had my pool for 1.5 years. I tore down my filter 4 months after the original build to clean it after the build, but other than that I have backwashed it just twice to clean out the DE that had been in there for 6 months. I have read here that many people with large DE filters never see an increase in pressure and just backwash once or twice a year.

You definitely have a larger debris load in your pool compared to mine, so your pressure might increase over time. I wouldn't worry too much if you don't see a rise in pressure as long as your gage returns to zero when the pump is off.