Adding DE after EACH backwash while shocking?

[stricttime]

Quote from TYGSBIASO sticky: "DE filters will often need to be backwashed a couple of times a day for the first day or two."

Does that mean I have to add 12 scoops of DE medium (my normals) each time I backwash? That's a lot of DE. Just want to make sure.

BTW, shocking pool for first time in 4 years! Never had a bit of algae until this week

 

[jblizzle]

Yes. You can not run water through the filter without DE for more than a few minutes (especially when the water is dirty) or you will clog up the grids with debris.

Is 12 scoops the recommended weight? After a backwash you usually only want to use about 80% of the recommended amount since the backwash is not that thorough:
use-and-care-for-de-filters-t4086.html

 

[woodyp]

Have to add if you backwash to have something to catch the rest.

 

[techguy]

I would say you only need to backwash if you are getting the pressure increase that justify the backwash that removes your DE. I have a Hayward that can be bumped to "re-generate". It redistributes the DE so the pressure go back down. I have not truly "backwashed" my filter. I take it apart and clean it. The need to completely dump and re-fill only happen if you are filtering a "swamp" with a DE.

I have good luck if I shut the pump off, let the algae and junk sink to the floor of the pool and then vacuum to waste.

that said, I have had to change the DE several times in a day IF the swamp needs to be cleared. Yes, it took a whole bag of DE to do this but DE is relatively cheap (relative to other filter media costs)

 

[stricttime]

The company that installed my pool instructed me to add 12 scoops of DE after each backwash. If I can get by with less, I'd be happy.

I don't have a swamp. Just algae growing on the walls a little bit. Had my nephews in town last week; despite the outdoor bathroom, not sure they ever used it.
My test results this morning:

FC 4
CC 0
CYA 60
Ph 7.4 (lowered for shocking)

Added bleach and am waiting to test again. TPC recommended a shock value of 18ppm. Will brush the walls in about an hour.

 

[jblizzle]

I would highly suggest you weigh the DE yourself ... there can be quite a variation in the amount of DE mass fits in a container depending on how well you pack it.

 

[stricttime]

Ok, so I need 6 lbs, according to the manual. The manual says nothing about adding less for a backwash; in fact, it refers back to the chart in the start up section. Can I get away with 4.8 lbs?

 

[techguy]

I looked at the instructions for Jandy DEV 60 and it appears they assume you back wash the filter 1-5 times until 100% of old DE is washed out of the filter.

I guess is depends on how clean the backwash made the filter.

I find I am happier just opening the filter and cleaning the grids (fingers in my case) with a hose before rebuilding the filter and adding a 100% charge that I know is 100% clean. It only takes me 30 minutes of so to do this. I do NOT have the same filter.