Did I just ruin my filter?

[mrluckies]

I've got a Hayward de4820 de filter. I cleaned the whole thing before putting it away for the winter. I opened it and looked at it before starting the pool this season, it looked ok so I closed it back up. I started vacuuming the pool to waste and had problems with the vacuum (there's another post I put about this). While trying to diagnose the vacuum, I ran the pump with water going through the filter and didnt add any de. I figured I'd have to clean it quickly because of all the junk from the vacuum. While trying to figure things out, I found the manual for the filter and it says not to run the filter without de for more than 2 minutes. Wish I would have found that sooner. So did I screw things up? And if so, how do I fix it.

with the the pump running and trying to vacuum, the vacuum doesn't work well and there's very little water coming out the jets. I'll try disassembling the filter tomorrow and spray it with a hose. Pressure is almost 20 psi. When I put on recirculate, pressure is 10 psi and good pressure out the return jets.

 

[cowboycasey]

Welcome to TFP

Take the panels out and clean and inspect them for holes or tears, replace any that are damaged

replace and refill with DE

 

[mrluckies]

thx!

I did all that and it seems to be working fine! I have a 48sqft filter. Since it was clean from winterizing I added the full 6 lb bag of de as recommended by the filter instructions. Pressure was about 15 psi which is what the previous owner said it should be.

Pressure got high this evening (just opened the pool and a lot of crud) so I back washed. I'm confused on how much de to add. Your video "how much de to add" said 2-3 scoops for a 48. Your other video "...ultimate guide" to back washing said to use 4 scoops of de for a 48.

I dont have a de scoop, but the previous owner said 2-1/2 1lb coffee cans of de after back washing. I had a 11.3oz coffee can, so I figured that 2-1/2 of 1 lb coffee cans is actually 40 oz, or about 4 of the 11.3oz coffee can.

I also bought a 4.5 cup measuring cup since it was only 88 cents. I filled the 11.3 oz coffee can with water and then dumped it in the measuring cup. It worked out to 1 liter of water or about 4 cups. I dried it and put it on the scale to zero the scale. Then i added de to the 1 liter level (after tapping to get it to settle) and weighed it. It came to just under 1 lb. I added de to the 4.5 cup level (after tapping to get it to settle) and weighed it again. This time it was 1lb.

Ive heard some people say after back washing you need 80% de. Since mine is a 48 sqft and needs 6 lbs when completely clean, then 80% after back washing is about 4 lbs or about 4 scoops which per above is about 2-1/2 of a 1lb coffee can. Does this seem right?

how do you know when there's too much de or not enough?

I decided to add 3.5 scoops from the measuring cup which is about 3.5 lbs.
pressure seemed ok and was about the same as when I had a clean filter and added 6lbs.

 

[cowboycasey]

If your pressure came back the same you should be good

 

[jblizzle]

Sounds like you are good to go. There are a few articles about DE filters in Pool School. I find you are much better off weighing the DE than relying on scoops.