Hayward EC50AC pumping green back in pool???

When filter gets tuned on, it shoots what looks like green algea back into the pool for about 10-15 sec, then return water clears up. I've been backwashing very frequently this year, and when I first bw, there's no cloud at all. I bw yesterday and bumped filter 20x before turning pump on and did it until water ran clear (3 - 4 times).

Pressure starts at 10PSI and usually jumps 2-4PSI before I BW. Using about 4-4.5lbs of DE to replace after bw (filter says to use 5lbs DE). Pool water has been cloudy and there's some green on the bottom of the pool. I have a 27' agp and been adding 3 bags of shock per week + Cholrine tabs. Running filter 4hrs in the AM and 6hrs at night. Chemistry looks to be good. Today, pool water looks to be clear but cloudy towards the bottom. I bought this filter used, but it was cleaned last year.

Any suggetions?

Thanks.

If I'm not mistaken, DE filters will allow live algae to pass through back to the pool. I would put the filter on "recirculate", shock the pool until the algae is dead, and then put it back in "filter" mode to let it clear the dead algae from the pool.
What is your stabilizer level, and how high is the chlorine level going when you shock it?

Checked Chlorine level today using test stip and it came up as "OK". I vaccumed the pool and backwashed the filter until water ran clear. I added about 9 - 13oz coffee cans worth of D.E. back to the filter (should = 4.5lbs of D.E.). Ran the pump again and the water out of the return was clear. I'm going to run the filter all night and see what the pool looks like tomorrow.

Thanks

Test strips that just say OK are going to get you in trouble. You really need a good kit. We recommend the Taylor K-2006 or 2006C (same kit, larger bottles). Take a look at the Amazon link in my signature. It will show you the kit. However, we only suggest purchasing it from Amato Industries and their website is down right now. (Other sellers are shipping the K-2005 by mistake and you don't want that one.) So, until the website is up, orders have to be made by phone. Their number is 800-992-6286.

Welcome to the Forum!

Please check out this thread for some DE filter info.

Your EC50 won't let you 'vacuum to waste' (I can give you a way to do it, if the algae and frequency of bumping the filter is too often for you ;) ) Read the article I linked to and ask of me any further questions you may have :)

Since last post, I've run the filter for 24 hrs on the first day, then 10 hours per day after. So far I still see green shooting back into the pool, but a lot than before. The pressure went up from 10 to about 15 after the first 8- 12hrs of running the filter, and I've had to bump the filter at least 3 times since first putting in the 9 - 13oz coffee cans of D.E. Pool is a lot clearer than before, but I am still getting some green on the bottom of the pool (again, not aas much as before). I have not used any Algecide yet, is it time I start to? I've been using chlorine tabs in floating chlorinator, and shock to clear up the algea in the pool.

It's also been very hot in the Northeast this week.

It sounds to me like you don't have enough chlorine for your CYA level. If you are using pucks (tabs), you are adding more CYA, and need even higher chlorine to compensate.
You don't need algaecide- you need more chlorine; how much depends on actual amount of CYA;
If you can get a water sample to a pool store, they can check your CYA level- then you'll know how much chlorine you need to maintain to shock (kill all the algae- probably for a few days, not just one dose!)
and then what level to keep to avoid algae in future...